The History of Invasiveness

Marseilles fig – Thomas Jefferson’s passion for figs helped propagate this variety in Virginia. In 1809, Jefferson wrote to Dr. William Thornton, a close friend and architect: “I will take some occasion of sending you some cuttings of the Marseilles fig, which I brought from France with me, & is unquestionably superior to any fig I have ever seen.”

The story of animal, insect and plant invaders is as old as the world itself. When humankind first began to roam, these beings tagged along. In strange new lands, the human instinct to collect unique specimens was born. So bits and pieces of non-natives came back with them – if indeed, these peoples ever returned to their points of origin.

From the tea-horse trade route in ancient Tibet to the Silk Road trade across Asia, Russia, Arabia and Africa into Europe, humans have moved about in search of economic opportunity. Certain plants and animals have been successfully raised far from their native regions when there were similarities in soil and climate: cotton, indigo, tobacco, rice, silk and wool come to mind along with all our domesticated animals. Other peoples moved to find religious freedom, escape tyrannical regimes, or just to have more living space. Whether intentionally or inadvertently, plants, animals and insects came with them.

By the eighteenth century, the quest began to find plants with beauty and ornament, hardiness, resiliance, disease resistance or unusual form or color. Collectors such as our founding fathers, George Washington and Thomas Jefferson, continually sought these qualities in their garden plants while keeping an eye out for species with economic or useful value to the new country. The Dutch collected bulbs from Turkey. The Victorians sent plant explorers around the world to bring back new curiosities. Such searching continues in the field of horticulture with modern day plant explorers like Dan Hinckley and Darrell Probst, as well as woody plant selector and hybridizer Dr. Michael Dirr.

Seeds have several ways to travel: they can float, stick, or blow. They can be eaten by animals like birds, pass through their digestive systems, and germinate in place. Bits of some roots or stems can grow readily if cut on purpose or acidentally. Now that we move about ever more widely in the 21st century, the movement of invaders has quickened. Natural controls in the land of origin, such as insect predators, host-specific funguses or herbivores, do not always accompany the invading plants. It may take eons for such controls to “catch up.” Meanwhile, our own native plants have evolved in place with their own control systems intact. And they may not be able to withstand the quickly moving, overpowering characteristics of many invaders.

Bringing the taste for non-native plants home to our own Northeastern United States:

Leslie Mehrhoff

Leslie J. Mehrhoff worked for the Department of Ecology and Evolutionary Biology at UConn as the curator of the George Safford Torrey Herbarium. He was involved in organizations including, but not limited to, the Connecticut Botanical Society, New England Wildflower Society, and the Torrey Botanical Club. He also participated in various committees such as the Arnold Arboretum at Harvard University, CT chapter of The Nature Conservancy, The CT Invasive Plant Working Group, and served as one of the Invasive Plant Atlas of New England Project Managers.

• David Fairchild, plant explorer extraordinaire for the USDA in the early 1900s, had trouble propagating kudzu from cuttings but then had overwhelming success with seeds (he also collected what turned out to be many economically and culturally successful crops such as oranges and avocados)
• E. H. Wilson, Keeper of the Arnold Arboretum in Boston in the 1920s and 30s and a plant explorer in his own right, wrote about shrubs with berries for birds and recommended privet and buckthorn (as well as native viburnums and a host of “good” plants)
• State extension service agents wrote pamphlets in the 1950s through 70s advocating the use of many non-native exotic plants for erosion control and wildlife forage, including multiflora rose and autumn olive
• Most American yards today are 80% lawn and 20% non-native ornamental shrubs that provide absolutely no nutritional value to our native insects, birds and wildlife per the research of Douglas Tallamy, Professor of Entomology at the University of Delaware and best-selling author
• Lurking at the edges of these yards are a legion of non-native plant invaders that are spiraling out of control with the potential to destroy native ecosystems, change soil chemistry, biology, and structure while creating early season shade in monocultures that wipe out the native plant understory over time
• Invading continues: Asian Longhorned Beetle, Emerald Ash Borer, Hemlock Woolly Adelgid, Gypsy Moth, Colorado Potato Beetle, and numerous other insect pests have become scourges in our time and have damaged both native and non-native plants along with field crops

The field of conservation biology is a young science. The late Dr. Leslie Mehrhoff, member of the Department of Ecology and Evolutionary Biology at the University of Connecticut and Curator of its Herbarium, was one of the early researchers into the science of invasiveness. In 1999, a group of experts in horticulture, conservation, natural resources, agriculture, academic science and land management convened in Massachusetts under the aegis of the Executive Office of Environmental Affairs. They identified themselves as the Massachusetts Invasive Plant Advisory Group (MIPAG). This entity turned to Dr. Mehrhoff’s research as a starting point for their work on the question of identifying and listing invasive plants. A similar relationship developed in Connecticut between Dr. Mehrhoff and the Connecticut Invasive Plant Working Group, founded in 1997.

MIPAG released a document in 2005 listing plants classifed by scientific criteria of Invasive, Like Invasive, Potentially Invasive, or Evaluated but not meeting Criteria of Invasiveness. This list was last updated in 2016 and is found at, and the Connecticut list can be viewed at Another valuable resource is the website of the Invasive Plant Atlas of New England,, continually updated by trained volunteer field spotters and professionals. There is a smart phone app to report sightings of invasives directly from the field. Lists include plants, insects, diseases and wildlife.

Also in 1999, a group of NOFA members from Massachusetts and Connecticut involved in the landscape business banded together to meet monthly under the leadership of Dr. Kimberly Stoner. Our goal was to write standards for the organic care of landscapes, modeled after what existed for organic farmers. We would do that and more, going on to develop an annual accreditation course to train land care professionals and presenting a series of public outreach lectures to raise awareness of this alternative to traditional chemical- and pesticide-based landscaping. I was fortunate to be a part of the group at the same time that I began my own organic landscape gardening company.

David Fairchild

David Grandison Fairchild (1869 – 1954) was an American botanist and plant explorer. Fairchild was responsible for the introduction of more than 200,000 exotic plants and varieties of established crops into the United States, including soybeans, pistachios, mangos, nectarines, dates, bamboos, and flowering cherries. Certain varieties of wheat, cotton, and rice became especially economically important.

We were able to adopt much of the organic farming standards. However, we noticed that there was no mention of invasive plants and how to deal with them. Donald Bishop, one of our number, was charged with researching and writing this section. He was at the time a member of the new MIPAG entity and owner of an organic land care business. With each of the five succeeding editions of the Standards for Organic Land Care, this chapter has had an update. Now entitled “Native, Exotic and Invasive Plants,” this section of the Standards is worth reading (

In the nearly 20 years since the writing of the Standards, I notice that clients are now much more aware of which plants are invasive and which are non-invasive or native. There are a few people who request that we leave the invasive plant in place, saying “at least it’s green” or “it screens me from my neighbor.” We work carefully to educate these clients, dropping nuggets of wisdom and leading by example. In time, we will replace those outlying invasive plants with a native alternative.

Most states have watch lists or lists of prohibited plants that are published online for reference. Burning bush, red barberry and Norway maples are no longer propagated and sold by nurseries, at least in this area, but may be available on the Internet from other states. Buyer beware! However, these and other invasive species still grow in many yards.

It is up to us individually to create what Doug Tallamy is calling “Homegrown National Park” of at least 80% native plants in our own backyards, nourishing the caterpillars and the birds that consume them. This web of life is fragile and oh-so important to our own lives.

Recommended Reading List:

Fairchild, David, The World Was My Garden: Travels of a Plant Explorer. New York: Charles Scribner’s Sons, 1943.
Grimshaw, John. The Gardener’s Atlas: The Origins, Discovery and Cultivation of the World’s Most Popular Garden Plants. London: Quarto Publishing, 1998.
Shepherd, Sue, Seeds of Fortune: A Gardening Dynasty. New York: Bloomsbury, 2003.
Spongberg, Stephen, A Reunion of Trees: The Discovery of Exotic Plants and Their Introduction Into North American and European Landscapes. Cambridge: Harvard University Press, 1990.
Tallamy, Douglas, Bringing Nature Home. Portland, Oregon: Timber Press, 2007.
Tallamy, Douglas, Nature’s Best Hope. Portland, Oregon: Timber Press, 2020.
Todd, Kim, Tinkering with Eden: A Natural History of Exotics in America. New York: W. W. Norton & Co., 2001.
Wilson, E.H., Aristocrats of the Garden. New York: Doubleday, Page and Company, 1917.
Wulf, Andrea, Founding Gardeners. New York: Alfred A. Knopf, 2011.
Wulf, Andrea, Brother Gardeners: Botany, Empire and the Birth of an Obsession. London: William Heinemann, 2008.

Priscilla Hutt Williams is Founder and President of Pumpkin Brook Organic Gardening in Townsend, Massachusetts and a co-author of the first edition of Standards for Organic Land Care: Practices for the Design and Maintenance of Ecological Landscapes, 2001.

We Came Over on the Mayflower, Too!

Feral Pigs

Feral Pigs


1539 Feral pigs, Sus scrofa, begin with the introduction of Spanish domestic stock in Florida by Hernando de Soto; whether the release was accidental or intentional is unknown.

1600s Scots pine, Pinus sylvestris, native to Europe and Asia, one of the first trees introduced by early European colonists, perhaps as windbreaks, erosion control, and a source of herbal medicine, lumber, and bedding: needles were used as a bedding known as “pine wool.”

— Purple loosestrife, Lythrum salicaria, native to Europe and Asia, introduced in ballast and likely in livestock bedding, fodder, and perhaps even in sheep fur as soon as colonists began to arrive.

Chinaberry Tree

Chinaberry Tree

— Yellow toadflax, Linaria vulgaris, native to Eurasia, introduced during colonial times as an ornamental, as a dye, and a medicine. By 1759 John Bartram found it invasive.

1606 Rock pigeon, Columbia livia, native to Eurasia, is introduced to Port Royal, Nova Scotia, by French settlers as a domesticated food source. It is likely that many other introductions occurred over the centuries.

1620? Dandelion brought by the Pilgrims on the Mayflower, to be planted as a medicinal crop and used in wine-making. Or perhaps it arrived with the Jamestown settlers. Or even earlier, with the Spanish. Some even consider it native to North America.

1620? Fennel, Foeniculum vulgar, also known as anise, sweet fennel, aniseed, and sweet anise likely arrived on the East coast with the first European settlers. Native to the Mediterranean, it was introduced in California at least by 1880, where it has escaped from cultivation repeatedly.

1620? Lamb’s quarters, Chenopodium album, also known as goosefoot and fat-hen, introduced by northern European settlers as a spring green.

Brown garden snail

1672 Burdock appears as “The great Clot Bur” in John Josselyn’s list of “Plants as have sprung up since the English Planted and kept Cattle in New-England,” published in London in New Englands Rarities Discovered.

Early 1700s Common mullein, Verbascum thapsus, native to Eurasia, introduced for its medicinal, dyeing, and fish-killing properties. By 1759, it appeared on John Bartram’s list of worst plants introduced by English colonists. By 1818, it had spread so much that Amos Eaton, author of the first Flora for the Northern states, thought it was native.

— Dog rose, Rosa canina, native to Europe, Africa, and Asia, introduced by early settlers, who used it as root stock. It can now be found growing wild along roadsides, coastlines, and wet, sandy areas.

— Common yellow oxalis, Oxalis stricta, and creeping woodsorrel, Oxalis corniculata, native to Europe, introduced by early settlers, who knew of their antiscorbutic properties.

— Gray garden slug, Deroceras reticulatum, native to Europe, accidentally introduced in dirt arriving with early settlers. Slugs’ presence confirmed by 1843 near Boston, New York, and Philadelphia harbors, the beginning of a nationwide career as one of our most successful synanthropes.

1727 English ivy, Hedera helix, native to Europe, western Asia, and northern Africa, introduced by European colonists as an ornamental.

1736 Asian or Oriental bittersweet, Celastrus orbiculatus, a vine native to temperate eastern Asia, introduced as an ornamental. Naturalized plants collected in Connecticut in 1916. Now naturalized in 21 of 33 states where it’s cultivated.



1745 Silktree or mimosa, Albizia julibrissin, native to Asia, arrived with early colonists, as a medicinal and a forage plant. Or in 1785 (if you’re from the South) it arrived when the French botanist André Michaux planted it in his botanic garden in Charleston.

Mid-1700s Woolly mullein, Verbascum thapsus, native to Europe and Asia, introduced to Virginia as a piscicide (the leaves contain rotenone, which can kill fish) and an insecticide.

1756 Norway maple, Acer platanoides, introduced in Philadelphia by John Bartram.

1759 Broad-leaved dock, Rumex obtusifolius, native to Eurasia, listed by America’s first botanist and nurseryman John Bartram as one of the introduced plants “most troublesome” in Pennsylvania.

— Scotch thistle, Onopordum acanthium, Bartram claims, was introduced by a Scots minister who arrived with a bed stuffed with thistledown, which was soon replaced with feathers, releasing a few thistle seeds into the wild.

— St. Johnswort, Hypericum perforatum, native to Eurasia, listed by Bartram as an ornamental gone invasive and proving poisonous to livestock.

— Oxeye daisy, Leucanthemum vulgare, native to Europe, introduced as an ornamental, made Bartram’s list of invaders, too.

1760s Scotch broom, Cytisus scoparius, native to western and central Europe, imported as an ornamental by John Bartram.

multiflora roses 1769 Domestic pigs released in California.

Late 1700s Chinaberry tree, Melia azedarach, native to Asia, introduced by French botanist André Michaux.

1784 Tree-of-heaven, Ailanthus altissima, an Asian sumac, introduced by William Hamilton in Philadelphia.

1800? Common buckthorn, Rhamnus cathartica, native to Eurasia, introduced near Nova Scotia for planting along fences and for wildlife shelter; widespread by 1900s.

Early 1800s Tamarisk, Tamarix spp., introduced into the US, mostly from Asia, some as ornamentals, some to be planted as wind-breaks or to stabilize stream banks. By the 1990s the smaller deciduous species had invaded most Southwest desert riparian habitats.

— Japanese honeysuckle, Lonicera japonica, a vine native to eastern Asia, introduced to Long Island as an ornamental and ground cover, spreads through the nursery trade. Wildlife managers later use it for erosion control and as winter forage for deer.

1814 Sowthistle, Sonchus spp., native to Eurasia, probably introduced accidentally as an imported seed contaminant, is first reported in Pennsylvania. It is currently found in all states.

1817 European green crab, Carcinus maenus, first reported near Cape Cod.

1840 European common periwinkle, Littorina littorea, first described in North America, is thought to have arrived on ballast rocks on ships from Great Britain plying the timber trade, Britain needing imported wood to build ships, having used up all its native trees.

Mid 1800s Tree-of-heaven brought into California during the Gold Rush, mainly by the Chinese; it remains in many ghost towns, long after the miners have gone.

1850 Gold Rush rats: Alien rodents storm San Francisco and Sacramento. T.A. Barry and B.A. Patten write in Men and Memories of San Francisco in the Spring of ’50 (Bancroft, 1873): “The rats of San Francisco and Sacramento in 1850, and up to the middle of the year 1853, were something wonderful. . . The little, four-footed, rodent devils worked damage only second to the fires of that time. . . Zinc and tins were nailed about the floors and lower boarding, like sheathing on a ship, and signs assuring ‘rat-proof storage’ were plentiful and necessary. At dusk, the rats ventured boldly out upon the streets, racing and scampering incessantly. . . . Pedestrians and new comers felt, as they walked among the countless swarm, a constant apprehension of treading upon the wicked little vermin; nor was the new comer alone so annoyed. We never could cure ourselves at times, of suddenly halting and lifting our hands quickly upward, when some big fellow sprang within an inch of us, or struck us full and heavy, as was not uncommon. . . . A terrier dog, or a good cat, commanded a big price in those times. The captain, cabin-boy, cook, or sailor who chanced to bring with him one of those much-coveted creatures, found solid consolation in separating from his faithful companion of the voyage.

“Every dog or cat of them, however, became poisoned and off duty, on the sick-list very soon, the result of their incessant labors. As time went on, and brought more dogs and cats, the rat commune was thinned out, defeated and reduced to the ordinary number; so that the citizen of today cannot, like the early resident, distinguish the rat of Valparaiso, the rat of Canton or Singapore, the long, white, pink-eyed rice-rat of Batavia, the New York, Boston or Liverpool wharf-rat, nor yet the kangaroo rat from Australia–so well known and readily recognized in the days when they held high carnival in our streets, warehouses and dwellings.”

1850s Brown garden snail, Helix asperse, arrives in California when French snail farmers bring escargot to the Gold Rush––a creature that would become a notorious agricultural and horticultural pest, especially in citrus groves.

~1850s Bullfrogs introduced to California to feed gold miners, after they had eaten the native red-legged frogs to near extinction.

1860 Burning bush, Euonymus alatus, native to northeast Asia, officially named. First dwarf form appears in Springfield, Massachusetts, before 1928. Various cultivars become popular landscape shrubs and roadside hedges, then escape cultivation throughout the eastern US and Canada.

1868 Garlic mustard, Alliaria petiolata, introduced from Europe by early settlers, is first recorded outside cultivation, on Long Island.

1875 Japanese barberry, Berberis thunbergii, introduced via seeds sent from Russia to the Arnold Arboretum in Boston; intended as a substitute for the European barberry, which the early colonists had introduced and used for dyes and jams, after it was discovered to carry wheat rust.

1876 Kudzu, Pueraria montana, introduced at the Japanese pavilion at the Centennial Exposition in Philadelphia, promoted as an ornamental and a forage crop.

—Torpedo grass, Panicum repens, native to Africa and Eurasia, possibly introduced into Louisiana, is first collected near Mobile, Alabama.

1877 Common carp, Cyprinus carpio, native to the Caspian and Aral Seas, imported from Germany by the US Commission of Fish and Fisheries, in response to overharvesting of native species and to the need to feed the growing human population. Official stocking lasted for 20 years, reaching almost every state and territory, with fish often being released from railroad tank cars at bridge crossings. They established so well that efforts at eradication began almost as soon as stocking ended.

1877 Japanese knotweed, Fallopia japonica, is introduced via Britain, herbarium records show, as an ornamental and for use in erosion control.

1883 First introduction of brown trout, Salmo trutta, into the United States by US Fish Commission to Michigan State. After trout eggs, brought over from Europe, were raised at a local hatchery, the fish were released into the Pere Marquette River. Brown trout also introduced into New York through the Caledonia Fish Hatchery.

1884-85 Water hyacinth, Eichhornia crassipes, introduced into New Orleans at the World’s Industrial and Cotton Centennial Exposition. Plants taken back to Florida by a visitor were later put into the St. Johns River.

1886 Multiflora roses, Rosa multiflora, native to Korea, eastern China, and Japan, imported for use as root stock, expands aggressively by suckering. Now classified as a noxious weed in 12 states and in some places is illegal to plant.

1890-91 European starling, Sturnus vulgaris, introduced: one hundred released by the American Acclimatization Society in Central Park, part of an alleged effort to introduce all 64 bird species mentioned in Shakespeare.

1891? First use of the term invasive species. An article in The Indian Forester notes: “As the species [purple loosestrife] can exist under different climatic conditions and is an invasive species, it has extended far beyond its original home.”

1893 50 wild boars imported from the Black Forest by railroad executive and robber baron Austin Corbin released in a 20,000-acre enclosure in New Hampshire for sport hunting.

1899 Nutria, Myocastor coypus, introduced into California for fur farming. The rodents fail to reproduce.

~1900 Russian knapweed, Acroptilon repens, introduced to Canada accidentally, along with alfalfa seed imported from Turkestan. Around 1910-1915, it was similarly introduced to California.

Early 1900s Coral bush, Ardizia crenata, introduced into Florida from Asia as an ornamental. By 1982 it was found in the wild.

1905 Air potato, Dioscorea bulbifera, introduced to Florida as an ornamental vine and an edible tuber from tropical Asia via Africa; by the early 1970s it is recognized as a statewide pest.

1910 Wild taro, Colocasia esculenta, had initially been introduced much earlier by slaves who had brought corms from Africa, but it did not spread in the wild until promoted by the USDA to farmers as a potato-substitute.

1923 Red Swamp crayfish, Procambarus clarkii, also known as Louisiana crayfish, crawdad, and mudbug, is introduced to Hawaii as a food source for bullfrogs. Native to the south-central United States, and northeastern Mexico, it has been introduced, often deliberately, through much of North America, Europe, Asia, and Africa. Farmed crawdads are now imported into the US from China.

1930s Nutria imported for fur farms, and promoted as “weed cutters,” in Louisiana, Ohio, New Mexico, Washington, Michigan, Oregon, and Utah. Several state and federal agencies release nutria to promote fur trade and control aquatic vegetation. Now found in 15 states, it has been introduced to every continent outside its native South America except Australia and Antarctica.

1930s Red Imported Fire Ant, Solenopsis invicta, identified after Brazilian ships unloaded ant-infested cargo in the port of Mobile, and a 13-year-old boy–a certain E.O. Wilson, as he would later be known–reported the first colony of Red Imported Fire Ant in the US.

1936 (possibly earlier) Cane toad, Bufo marinus, native to northern South America, introduced to Palm Beach County, Florida, in a misguided attempt to control pest beetles in sugar-cane fields.

— Amblyomma rotundatum, a South American tick, suspected to have entered the United States as a parasite on the cane toad, either in the 1930s or in later escapes and releases. The tick is now established in South Florida.

1938 Asian clam (Corbicula fluminea), native to southeastern Asia and Africa and imported to Washington State, possibly as a food source, begins its spread into the nation’s major waterways. Any intake pipe they can clog, they will.

1947-48 Locals introduce nutria throughout east Texas because of its value as a furbearer and reputation as weed cutter.

1950s Green iguana, Iguana iguana, native to Central and South America, found in the Florida Keys, perhaps having stowed away in fruit shipments from Central America.
— Spike-topped applesnail, Pomacea diffusa, native to Amazonia, introduced to south Florida.

1962 Euell Gibbons publishes his first book, Stalking the Wild Asparagus, celebrating wild foods. Many of his chapters are about invasives.

1962 Northern snakehead, Channa argus, native to eastern Asia, imported for the Asian food market and for the pet industry in the United States, found in the wild in Maine.

1966 New York City parks commissioner Thomas Hoving calls the pigeon, Columba livia, a “rat with wings.” The phrase sticks.

1968 White-winged parakeet, Brotogeris versicolurus, native to the Peruvian Amazon, escapes from its birdcage in south Florida and is sighted by a biologist. Imports of the bird are banned in the 1990s; wild flocks in Broward and Dade counties grow.

1980s Asian carp, (bighead, Hypophthalmichthys nobilis; black, Mylopharyngodon piceus; grass, Ctenopharyngodon idelia; and silver, Hypophthalmichthys molitrix), imported into the southern US to eat the aquatic plants in aquaculture facilities, escapes into the Mississippi, swimming north.

— Eurasian collared-dove, Streptopelia decaocto, which spread throughout Western Europe in the mid-twentieth century, is introduced to the Bahamas from the Netherlands by a pet breeder in 1974. By the 1980s, it colonizes south Florida. Fueled by the seeds of backyard bird feeders, the species reaches Oregon in 1998.

1984 Spiny water flea, Bythotrephes longimanus, zooplankton from Eurasia, found in untreated ballast-water from freshwater Eurasian ports to Lake Huron. The flea, its eggs, and larvae catching in fishing gear have spread it to inland lakes and rivers.

1985 Lionfish, Pterois volitans, native to the Indo-Pacific, first documented off the coast of south Florida. Imported as a tropical fish for saltwater aquariums, lionfish disappointed hobbyists by devouring smaller fish and may have been dumped alive in open waters, where they soon spread. The species has since been observed from Venezuela to the Gulf of Maine.

1988 Zebra mussel, Dreissena polymorpha, introduced into the Great Lakes in ballast water from freshwater Eurasian ports.
— Asian shore crab, Hemigrapsus sanguineus, first recorded at Townsend Inlet, Cape May County, New Jersey. It was likely released by incoming international cargo ships during ballast-water discharge.

1989 Green crabs spread from US East Coast to San Francisco, likely in the algae used to pack New England bait-worms. El Niño-strengthened currents help them northward after fishermen dumped the algae overboard.

1990 Africanized Honey Bee, Apis mellifera scutellata, reached southern Texas via South and Central America. An African bee, imported to South America and crossed with a European one to increase honey production, the hybrid proved aggressive.

1990 Round goby, Neogobius melanostomus, a fish native to Black and Caspian Seas, is found in the St. Clair River, between Ontario and Michigan. Probably transported in ballast water, it has spread into all five Great Lakes, where it is a threat to many native fish as a voracious eater of eggs. The goby may play a role in botulism outbreaks, killing fish and birds.

1998 Two veined rapa whelks, Rapana venosa, native to the Northeast Pacific Ocean, are trawled from the lower James River, Virginia. For decades, the species had been spreading around the Atlantic: 1947, the Black Sea. 1957, the Sea of Azov. 1983, Venice. 1992, England and France. The whelk is likely here to stay: the US Geological Service admits, “There are no known cases of successful eradication of nonindigenous marine invertebrates in the United States.”

2000 Wakame Undaria pinnatifida, native to Asia, reported in California estuaries.

2002 Emerald ash borer, Agrilus planipennis, an Asian beetle, which likely arrived in wood packing materials used to ship auto parts and other products, identified in southern Michigan.

— Redbay ambrosia beetle, Xyleborus glabratus, native to Asia, detected near Savannah’s Port Wentworth. Thought to have infested wooden packing materials unloaded at the port, it spread quickly along the Georgia coast and into Florida and South Carolina, attacking trees in the laurel family and causing a wilt for which there is no cure.

2006 Burmese python, Python molurus bivittatus, first documented in Florida Everglades.

2009 Kudzu bug from Asia first documented in the southeastern US.

Invasive Species



An invasive species is an organism that is not indigenous, or native, to a particular area. Invasive species can cause great economic and environmental harm to the new area.

Not all non-native species are invasive. For example, most of the food crops grown in the United States, including popular varieties of wheat, tomatoes, and rice, are not native to the region.

To be invasive, a species must adapt to the new area easily. It must reproduce quickly. It must harm property, the economy, or the native plants and animals of the region.

Many invasive species are introduced into a new region accidentally. Zebra mussels are native to the Black Sea and the Caspian Sea in Central Asia. Zebra mussels arrived in the Great Lakes of North America accidentally, stuck to large ships that traveled between the two regions. There are now so many zebra mussels in the Great Lakes that they have threatened native species.

Native to the Indo-Pacific oceanic region, lionfish are quickly spreading throughout the coasts and coral reefs of the East Coast of the United States. Lionfish are voracious eaters and their venomous dorsal spines have helped to protect them so far from any natural predation in the Atlantic. Lionfish are popular in aquariums, but less popular in the Caribbean Sea and the Atlantic Ocean—they are an invasive species that outcompete native fishes for resources.

Introduced Species

Some species are brought to a new area on purpose. Often these species are introduced as a form of pest control. Other times, introduced species are brought in as pets or decorative displays. People and businesses that import these species do not anticipate the consequences. Even scientists are not always sure how a species will adapt to a new environment.

Introduced species multiply too quickly and become invasive. For example, in 1949, five cats were brought to Marion Island, a part of South Africa in the southern Indian Ocean. The cats were introduced as pest control for mice. By 1977, about 3,400 cats were living on the island, endangering the local bird population.

Other invasive species descended from pets that escaped or were released into the wild. Many people have released pet Burmese pythons into the Everglades, a swampy area of south Florida. The huge snakes can grow to 6 meters (20 feet) long. Pythons, native to the jungles of southeast Asia, have few natural predators in the Everglades. They feast on many local species, including white ibis and limpkin, two types of wading birds.

Invasive Species and the Local Environment

Brown tree snake

Many invasive species thrive because they outcompete native species for food. Bighead and silver carp are two large species of fish that escaped from fish farms in the 1990s and are now common in the Missouri River of North America. These fish feed on plankton, tiny organisms floating in the water. Many native fish species, such as paddlefish, also feed on plankton. The feeding cycle of the paddlefish is slower than that of the carp. There are now so many carp in the lower Missouri River that paddlefish do not have enough food.

Invasive species sometimes thrive because there are no predators that hunt them in the new location. Brown tree snakes were accidentally brought to Guam, an island in the South Pacific, in the late 1940s or early 1950s. No animals on Guam hunted the snakes, but the island was filled with birds, rodents, and other small animals that the snakes hunt. The snakes quickly multiplied, and they are responsible for the extinction of nine of the island’s 11 forest-dwelling bird species.

Many invasive species destroy habitat, the places where other plants and animals naturally live. Nutria are large rodents native to South America. Ranchers brought them to North America in the 1900s, hoping to raise them for their fur. Some nutria were released into the wild when the ranchers failed. Today, they are a major pest in the Gulf Coast and Chesapeake Bay regions of the United States. Nutria eat tall grasses and rushes. These plants are vital to the regions’ marshy wetlands. They provide food, nesting sites, and shelter for many organisms. They also help secure sediment and soil, preventing the erosion of land. Nutria destroy the area’s food web and habitat by consuming the wetland grasses.

Some invasive species do great harm to the economy. Water hyacinth is a plant native to South America that has become an invasive species in many parts of the world. People often introduce the plant, which grows in the water, because of its pretty flowers. But the plant spreads quickly, often choking out native wildlife. In Lake Victoria, Uganda, water hyacinth grew so thickly that boats could not get through it. Some ports were closed. Water hyacinth prevented sunlight from reaching underwater. Plants and algae could not grow, preventing fish from feeding and reproducing. Lake Victoria’s fishing industry declined.

Invasive species can also damage property. Small zebra mussels clog the cooling systems in boat engines, while larger ones have damaged water pipes at power plants throughout the Great Lakes region.

Eradicating Invasive Species

Officials have used a variety of methods to try to eradicate, or get rid of, invasive species. The cats on Marion Island were infected with a virus, for instance.

Sometimes other species are introduced to control an invasive species. In Australia, prickly pear cactus, which is native to the Americas, was growing out of control. The cactus was destroying rangeland, where ranchers raised livestock. The government brought in cactus moth caterpillars to eat the cactuses. The caterpillars are natural predators of the cactus.

Introducing insects can be dangerous, however. Sometimes, the insects also damage other plant species—they can become invasive species themselves. Chemicals have also been used to control invasive species, but they can sometimes harm noninvasive plants and animals.


Governments are working to educate the public about invasive species. For example, in the United States, international fishing vessels are warned to wash their boats before returning home. This prevents them from accidentally transporting zebra mussels or other species from one body of water to another.

Sometimes, communities approach invasive species like an invading army. Nutria in Chesapeake Bay destroy the natural habitat, as well as cost local governments and businesses millions of dollars each year. Environmental groups, business leaders, and government officials are concerned about the harm done by this invasive species.

Officials at the Blackwater National Wildlife Refuge, in the U.S. state of Maryland, worked with hunters to eradicate the 8,500 nutria in the refuge. Hunters waded into specific areas of the marsh during specific times of the year. They tracked nutria using global positioning system (GPS) equipment and set traps that would kill the rodents. The hunters moved across the refuge in a massive, coordinated, west-to-east movement. In winter, the ice on Chesapeake Bay prevented the nutria from swimming away. Hunters could shoot them on sight.

The operation took two years, but nutria were eradicated from Blackwater National Wildlife Refuge. The wetland is slowly recovering.

Stowaway Species

Water hyacinth

Water hyacinth

Many invasive species first arrive in a new area on huge cargo ships that travel back and forth across the ocean. Ships take on ballast water in their home port. The weight of this water makes the ships stable while they travel across the ocean. When a ship gets to its destination, it releases the ballast water.

Ballast water is teeming with living creatures that were in the water at the port on the other side of the globe. Scientists estimate that between 5,000 and 10,000 species are traveling around the world in ballast water at any given time. The first zebra mussels in the Great Lakes probably arrived in ballast water.

Invasion of the Turnips:

Bryan OHara

Bryan O’Hara farms organic vegetables in Connecticut

There was a time, not so long ago, when weeds were just considered weeds. There were no “invasive” weeds. The concept of an invasion of weeds appears to be linked to the human separation from the lessons of nature. A weed is, of course, a plant which a human considers out of place. In nature there are no weeds, only plants covering the earth offering their unique benefits to the forces of life. Nature’s timeline is very, very long. From this perspective, nature can be seen to have little regard for the hurried demands of the human concerns of plants out of place. Weeds, or plants out of place, is a human perspective which is not consistent with nature’s perspective.

As farmers, we are concerned with plants out of place impacting our crops. With decades of experience in annual crop production, it has become very clear that such weeds are a signal from nature about how our agricultural practices are impacting the earth. In this sense the weeds become a mirror for the farmer to look into. Certain weeds can signal soil structure imbalances, some signal nutrient imbalance, some chemical contamination, and so on. When field conditions are well balanced and nature-benefitting agricultural approaches are taken, the farmer is rewarded with minimal weed “interference” and abundant, vigorous crops. Weeds invariably are of benefit to the agricultural field as they are well selected by nature to harness the sun’s energy and provide the benefits of this energy consolidation to the living organisms surrounding them. The weeds provide the soil with a physical cover as well, with all the associated benefits.

Almost invariably there is no bare soil in nature. Soils’ formation, continuance, and development are dependent upon consistent coverage with plants. Nature is very adept at maintaining this condition; farmers, however, are often not as adept. Weeds are nature’s cover crop, often superior to our “cover crop seed blends”, in diversity, vigor, and appropriate ability to bring life to the soil environment. We can assist this life-building process when we are paying close attention and have a willingness to cooperate and interact with nature, this being one of the most uplifting of human experiences. This engaging with natural forces in a cooperative farming endeavor is a humbling and awe inspiring experience when the complexity and interconnectedness of creation is glimpsed. However, oftentimes cooperation with nature in agricultural practices is not the case and farming results in detriment to the life force.


These barberries clearly delineate that different agricultural approaches were taken on the 2 sides of the stone wall, previous to the regrowth of this forest.  Nature’s plant selection denotes environmental conditions.

With so many distractions from the earthbound human’s role as caretaker and co-creators in the development and expansion of the living forces, much has deteriorated. Environment collapse is prominent as the impacts of pollution, war, and greed destroy living systems. Some basic examples include, but are not limited to, the air’s gaseous nature is altered by fumes of industry, including much vaporized herbicide. The rain falling through this environment picks up many pollutants and alters the soil environment. The soils themselves are often “treated” to various pesticides. The sun is blotted out by jet fueled chem trails and particulate matter from pollution. Radioactive fallout from nuclear sources, microwaving, electromagnetic disturbances, and far more — in response to such destruction, nature changes…

The soils alter their biological, chemical, and physical conditions under these influences. Many plants, insects, microbes, and animals cannot survive these changes, resulting in the observed “die-outs” of various species. The mode of decline for these species is often disease or other life-threatening pestilence. Often the disease is blamed for the die-out and humans fail to consider the environmental conditions that were the underlying cause.

Some of the obvious die-outs we have witnessed in Connecticut over the last few decades include the complete loss of several tree species including: the Chestnut, the Elm, and Red Pine. These are quickly being followed by the Spruce, the Hemlock, the Birch, the Aspen, the Sugar Maple, and the Oak. Actually, pretty much every tree species in now under significant disease and insect pressures, resulting in very sparse canopies and significant discolorations. “The trees are brown and the sky is white”, being a common condition. Most other plant species also develop significant disease conditions as well. The insect populations have also quickly followed the plant decline, with the decline of early spring pollinator populations on our farm probably approaching 99%, compared to a few decades ago. These earth changes are requiring strength and vigor of new plant species, in order to maintain vegetative cover over soil surfaces. It is not surprising that we are “invaded” by these new plant species, thanks to the earth’s wisdom.

To apply a preservationist approach to such rapidly evolving conditions is a difficult proposition. The earth needs to evolve to maintain its vitality, yet humans at the same time have difficulty letting go of the past. The approach to “invasive weeds” may benefit from this outlook, nature is wise in seeking to protect itself with these plants, yet we humbly ask for assistance in growing some of the plants we desire. This is how we approach farming as well. A gentle, careful approach where human and nature work together to create a living, thriving environment in a powerful symbiotic relationship. This provides the human life with much meaning, to be of benefit to life, as well as giving us plenty to do.

However this humble cooperative approach is rare, and instead we are faced with many who view these plants as an “invasion” — something to be battled against with all the weapons of war. This requires a certain level of arrogance to believe that nature knows not what she does, and that the humans know better. The battle against the enemy, which in this case is nature, is actually a battle against oneself, for when the interconnected web of life is witnessed, the face of the enemy on the battlefield is finally seen as one’s own. For now the battle continues, the enemy continually shifts forms; now an invasive plant, then an insect, a germ, a terrorist, or climate change. The approach is consistently one of war; pesticides, sterilizers, pharmaceuticals, bullets, bombs, and weather modification. The result is more suffering, death and destruction, long into the aftermath, all to the detriment of the forces of life.

Wineberries just will not invade!

Wineberries just will not invade!

Nature, in boundless compassion, constantly holding up the mirror for us to see ourselves.

A few years ago the local newspaper sent a reporter to one of our farmers markets for a story. The next day we were pleased to see a local farmer generously offering a taste of delicious wine berries to a curious customer, the wine berry being a less known raspberry relative. We were quite surprised when the next week a regulator from the state department of Energy and Environment (D.E.E.E.P.) came to inform us that our market was offering illegal berries for sale. Before being dispatched from the market he managed to provide us with a list of numerous plants that had, in legislative darkness, become illegal to cultivate. These included such plants as watercress, valerian, and wine berries, among many others. This legislation declared them “invasive species”. Actually, just previously to this event our local health department had informed us that though we could sell fruits and vegetables we could not give them away without a “sampling permit”. So our front page coverage was actually illegal sampling of illegal berries, but that’s another story.

The idea of being invaded by delicious, illegal berries was very attractive to us, so we set about trying to increase the wine berries on our farm. Unfortunately after years of encouragement the wine berries have absolutely refused to invade and all we have is a tiny patch of hardly productive plants. We have had similar experiences with watercress, and valerian. We can encourage them to grow but they certainly will not invade. Of course most plants are presently struggling in our environment, so this is not really surprising. Though some of the declared plants do seem vigorous enough to continue to thrive, hopefully more of the declared “invasive” plants will prove to be capable under our conditions.

Raw Turnips

Can raw turnips, recommended in Chinese medicine as a healthy food that fights the flu, become the next fashionable delicacy?

Despite the general environmental difficulties, we have still found the earth willing to provide us with abundant, healthful crops when great care in agricultural approach is applied. This was the case last fall when we were harvesting all the root vegetables for winter storage and sale. The shining stars amidst this abundance were the turnips and winter radishes, with absolutely astounding yields of perfect roots — the clear definition of a bumper crop. Unfortunately the market conditions for turnips has not fared well over the years, and even though almost all vegetable varieties have increased in consumption, the turnip eaters appear to be dwindling.

This led to charges against this writer of being an excessive Cancerian, in need of the security of many tons of turnips stored in the root cellar beneath his bed. Though on the surface I accepted these charges, secretly I suspected something else was afoot.

Happily this became clear when, in late winter, fear of the coronavirus first brought on frenzied buying of storage vegetables, followed by concerns about food shortages. Though a bit of the turnip did sell, it turned out that, more importantly, the stockpile of turnips brought great comfort and peace to the local community when we informed the many people that they were welcome to come and eat as many turnips as they could if social conditions deteriorated.

Following this came the realization that raw turnip and radish are primary vegetables for treatment and prevention of colds and flu in many traditions. We found while studying Chinese medicinal approaches that colds and the flu are often considered an excess of the “cool and damp”, and that raw turnip and radish bring balance to this condition. As well, when talking with an African American friend, she related a story from when she was a young girl in which her mother always made her eat raw turnip when colds or flu threatened. Though perhaps this mandatory approach has diminished her enthusiasm for turnip eating, we have, as a family, also appreciated the consumption of these raw or pickled vegetables for many such health conditions.

Garlic Mustard, offering us delicious food as it increases photosynthesis which benefits the soil as the tree canopies become sparse.  The consumption of these vigorous plants offers the particular nutrients and health-giving properties that assist our survival in the same environmental conditions.

Now that a more complete view of the great turnip excess of 2019/2020 can be seen, it becomes clear that the earth is still willing to provide in abundance what we most need. Quite a reassurance in these times of darkness. The darkness would have us not continue to create in a loving, cooperative association with nature. Yet the darkness also assists us in evolving, as we can bring an appropriate amount of light to balance the darkness. When we step back and look from above at our situation, we see that nature is clearly ready to continue to help us in this effort. Though many people are prepared for this time, there are still some who are just not ready to eat raw turnips.

Climate Change & Wildlife Health:

Climate change will have significant effects on the health of wildlife, domestic animals, and humans, according to scientists. The Intergovernmental Panel on Climate Change projects that unprecedented rates of climate change will result in increasing average global temperatures; rising sea levels; changing global precipitation patterns, including increasing amounts and variability; and increasing midcontinental summer drought. Increasing temperatures, combined with changes in rainfall and humidity, may have significant impacts on wildlife, domestic animal, and human health and diseases. When combined with expanding human populations, these changes could increase demand on limited water resources, lead to more habitat destruction, and provide yet more opportunities for infectious diseases to cross from one species to another.

Awareness has been growing in recent years about zoonotic diseases— that is, diseases that are transmissible between animals and humans, such as Lyme disease and West Nile virus. The rise of such diseases results from closer relationships among wildlife, domestic animals, and people, allowing more contact with diseased animals, organisms that carry and transmit a disease from one animal to another (vectors), and people. Disease vectors include insects, such as mosquitoes, and arachnids, such as ticks. Thus, it is impossible to separate the effects of global warming on wildlife from its effects on the health of domestic animals or people.

Climate change, habitat destruction and urbanization, the introduction of exotic and invasive species, and pollution—all affect ecosystem and human health. Climate change can also be viewed within the context of other physical and climate cycles, such as the El Niño Southern Oscillation (El Niño), the North Atlantic Oscillation, and cycles in solar radiation that have profound effects on the Earth’s climate. The effects of climate change on wildlife disease are summarized in several areas of scientific study discussed briefly below: geographic range and distribution of wildlife diseases, plant and animal phenology, and patterns of wildlife disease, community and ecosystem composition, and habitat degradation.

Geographic Range and Distribution of Wildlife Diseases

In the Northern Hemisphere, global warming has likely played a role in geographic shifts of disease vectors and parasitic diseases that have complex life cycles. For example, the black-legged tick, which carries and transmits Lyme disease and several other tick-borne zoonotic diseases in North America, has been expanding north into southern Ontario and western Ontario and Manitoba, and, more recently, into Quebec and the Canadian Maritime Provinces.

In Europe, a similar northward expansion of the European castor bean tick, which also carries and transmits Lyme disease, tick-borne encephalitis (TBE), and other diseases, has been reported in Norway and Sweden. On both continents, migrating birds carrying feeding ticks are likely the source of long-range expansion of the tick vectors and increasing environmental temperatures have likely permitted the ticks to become established in larger geographic areas.

Scientists also expect changes in disease distribution with changes in altitude. For example, climate warming may lead to year-round transmission of mosquito-borne avian malaria at higher elevations in the Hawaiian Islands, further threatening endangered native Hawaiian birds that have little or no resistance to the introduced disease. Currently, on the island of Hawai’i, avian malaria, caused by the parasite Plasmodium relictum, is limited to warmer elevations below 1,500 meters (or 4,920 feet). If the higher elevations become warmer as projected, mosquito activity and parasite development in these areas will increase. Conservationists are concerned that climate change may lead to increased avian malaria transmission throughout the year at increasingly higher elevations.

Phenology: Effects on Wildlife Disease
The timing of recurring seasonal biologic cycles of some plant and animal species has already been affected by climate change. The study of these seasonal cycles is called phenology. The timing of biological cycles, such as the arrival of a bird species in the spring and the availability of its preferred food source, is critical for successful breeding and survival. Several studies in Europe show that some migratory birds have changed their migration patterns in response to climate change by arriving earlier than records show historically. Significant population declines were reported recently for bird species that have not responded with earlier arrival, and the population declines have been interpreted as indicating the magnitude, and negative effect, in mismatch between bird arrival time and the onset of plants emerging from dormancy in spring. When an earlier emergence of plants from dormancy is combined with a mismatch in bird arrival time, critical food sources for returning birds might be past the period when they are most nutritious.

Variability in the timing of these biological cycles also can lead to increases or decreases in the risk for infectious disease, particularly diseases transmitted by mosquitoes or ticks. In Europe, transmission of TBE to humans often increases when warmer temperatures in the early spring result in the overlap of feeding activity of virus-infected nymphal and uninfected larval European castor bean ticks. Under these conditions, TBE is more readily passed between ticks feeding on small rodents. The period of viral infection is brief in tick-infested rodents, so when both stages of tick feed at the same time, more larval ticks become infected, and the risk for human infection increases. Cooler spring temperatures result in less feeding overlap of nymphal and larval ticks, and under these conditions, the virus-infected rodents have time to recover from infection and are less likely to pass the virus to feeding larval ticks.

At sites in North America, the same seasonal temperature effect has been observed in the transmission of the bacterium Borrelia burgdorferi, the pathogen or cause of Lyme disease, from infected nymphal black-legged ticks to uninfected larval ticks. When larval and nymphal ticks feed simultaneously, this not only contributes to the successful transmission of the pathogen to larvae, it also results in greater genetic diversity in this zoonotic pathogen (Gatewood and others, 2009). Climate change, by altering seasonal weather patterns, has the potential to affect these natural cycles.

Changing Patterns of Wildlife Disease

Figure 4. Human risk for tick-borne encephalitis in Europe

Figure 4. Human risk for tick-borne encephalitis in Europe is heightened in some years by slightly warmer temperatures in early spring that are associated with overlappng feeding of infected nymphal ticks and uninfected larval ticks. A slower rise in spring temperatures is associated with nonoverlapping feeding.

In nature, pathogens can be transmitted directly between animals or indirectly through intermediate “hosts,” such as infected prey or biting insects. Indirect transmission cycles are often affected by environmental conditions such as temperature and rainfall. Higher temperatures associated with climate change may contribute to an increase in pathogens within intermediate hosts and vectors, or increased survival of animals that harbor disease. For example, warmer summer temperatures in the Arctic now allow the lung nematode larvae often found in muskoxen to develop to the infectious stage within the intermediate host, the marsh slug, at a rate that has reduced the parasite’s life cycle from 2 years to 1 year.

Survival of another nematode, the brain worm of white-tailed deer, may also be increased by recently warmer temperatures and milder winters in the north-central United States and southern Canada. The parasite, which overwinters as larvae in snails and is accidentally eaten with plants, causes neurological disease in moose. Moose are already heat stressed by climate change and may be more susceptible to parasitic and infectious diseases. including the brain worm of white-tailed deer.

Changes in precipitation patterns also have a significant potential to affect patterns of wildlife disease through survival of disease agents or vectors and through effects on host parasite relationships. In the example of the brain worm of deer, increased precipitation also may result in increased survival of the snail populations, resulting in more exposure of deer to infected snails.

Community and Ecosystem Changes
Determining the effects of climate change on communities and ecosystems is difficult because the effects are likely to be highly variable, and this may be especially true for marine ecosystems. Since the 1980s, coral reefs in the Western Atlantic have suffered massive declines due to disease. It is likely that coral mortalities were initially due to widespread mortality of sea urchins, which allowed algal overgrowth of reefs, followed by environmental degradation and increased coral susceptibility to disease. Since the early 1980s, mass “coral bleaching” has been observed worldwide, especially following the major 1998 El Niño event, and it has been linked to higher sea-surface temperatures and to rising carbon dioxide levels that increase acidification of the oceans, which further weakens the coral structure. Corals are able to survive in nutrient-deficient waters because corals and the photosynthetic algae that live on them support each other. Corals that have lost these algae due to increased water temperature, changes in salinity or pollution may be susceptible to disease, leaving white coral skeletons, referred to as “coral bleaching”. Elevated temperatures will likely increase coral bleaching, which can lead to coral die-offs. Corals that fail to recover sufficiently may lead to loss of coral reefs and associated tropical marine life that depend on them for food and shelter. Coral bleaching has already been associated with significant declines in the diversity and population size of reef fish. Coral bleaching and declines in the physical integrity of reef systems also are anticipated to lead to further reductions in the complexity of coral reef ecosystems. As a result, local economies that depend on coral reefs for sustenance or tourism could be significantly affected by climate change.

Habitat Alteration
Climate change has caused dramatic changes in several macro- and microhabitats on Earth. While wildlife species are likely to be adaptable, within their physiological limits, in dealing with direct impacts of climate change on temperature and precipitation, their ability to respond to major physical changes in their environment, short of migration, is more limited. Along the Antarctic Peninsula, populations of Adelie Penguins are declining, because coastal ice no longer persists through the winter in many locations. In Antarctica, the Adelie Penguin is commonly a coastal bird found in areas where sea ice persists throughout the winter, because it relies on sea ice for access to feeding areas where upwelling ocean currents contain many krill and fish.

Climate change is also having a detrimental effect on microhabitats. Amphibian and reptilian populations have declined in the lowland forests in Costa Rica in part through the effect of climate change on the humid leaf litter microhabitat of the forest floor. Weather conditions also significantly affect the microclimates for nests and burrows. For example, in sea turtles, elevated temperatures may lead to altered sex ratios or loss of nesting beaches secondary to sea level rises. Temperatures outside the range of those that turtles can tolerate result in the death of the developing sea turtle embryos.

Questions to Ponder about Climate Change
Because of the uncertainty associated with the effects of climate change on the health of wildlife, domestic animals, and humans, we recommend four areas of study.

Figure 6. Extensive coral bleaching on reef, St. John, U.S. Virgin Islands Caroline S. Rodgers U.S. Geological Services

1. Long-term interdisciplinary projects can help determine climatic effects on biological factors associated with disease emergence, including species abundance, animal interactions and movements, vector populations). How might various physical, social, and economic factors contribute to disease emergence, persistence, and spread?

2. How are threatened and endangered free-ranging wildlife populations currently threatened by disease? How might climate change affect the current situation?

3. How will climate change play a role in the threat of wildlife associated water- or vector-borne diseases for free-ranging wildlife, other animals, and humans?

4. How will climate change play a role in the lives of native peoples who are dependent upon wildlife as a major source of food? Will wildlife population declines or wildlife-associated food-borne diseases threaten native peoples?

Invasives are a Threat to Wildlife

“Invasive species”—they may not sound very threatening, but these invaders, large and small, have devastating effects on wildlife.

Invasive species are among the leading threats to native wildlife. Approximately 42 percent of threatened or endangered species are at risk due to invasive species. Human health and economies are also at risk from invasive species. The impacts of invasive species on our natural ecosystems and economy cost billions of dollars each year. Many of our commercial, agricultural, and recreational activities depend on healthy native ecosystems.

What Makes a Species “Invasive”?

An invasive species can be any kind of living organism—an amphibian (like the cane toad), plant, insect, fish, fungus, bacteria, or even an organism’s seeds or eggs—that is not native to an ecosystem and causes harm. They can harm the environment, the economy, or even human health. Species that grow and reproduce quickly, and spread aggressively, with potential to cause harm, are given the label “invasive.”

An invasive species does not have to come from another country. For example, lake trout are native to the Great Lakes, but are considered to be an invasive species in Yellowstone Lake in Wyoming because they compete with native cutthroat trout for habitat.

How Invasive Species Spread

Invasive species are primarily spread by human activities, often unintentionally. People, and the goods we use, travel around the world very quickly, and they often carry uninvited species with them. Ships can carry aquatic organisms in their ballast water, while smaller boats may carry them on their propellers. Insects can get into wood, shipping palettes, and crates that are shipped around the world. Some ornamental plants can escape into the wild and become invasive. And some invasive species are intentionally or accidentally released pets. For example, Burmese pythons are becoming a big problem in the Everglades.

In addition, higher average temperatures and changes in rain and snow patterns caused by climate change will enable some invasive plant species—such as garlic mustard, kudzu, and purple loosestrife—to move into new areas. Insect pest infestations will be more severe as pests such as mountain pine beetle are able to take advantage of drought-weakened plants.

Threats to Native Wildlife

Invasive species cause harm to wildlife in many ways. When a new and aggressive species is introduced into an ecosystem, it may not have any natural predators or controls. It can breed and spread quickly, taking over an area. Native wildlife may not have evolved defenses against the invader, or they may not be able to compete with a species that has no predators.

The direct threats of invasive species include preying on native species, outcompeting native species for food or other resources, causing or carrying disease, and preventing native species from reproducing or killing a native species’ young.

There are indirect threats of invasive species as well. Invasive species can change the food web in an ecosystem by destroying or replacing native food sources. The invasive species may provide little to no food value for wildlife. Invasive species can also alter the abundance or diversity of species that are important habitat for native wildlife. Aggressive plant species like kudzu can quickly replace a diverse ecosystem with a monoculture of just kudzu. Additionally, some invasive species are capable of changing the conditions in an ecosystem, such as changing soil chemistry or the intensity of wildfires.

Examples of Invasive Species

Asian carp

Asian carp

Asian carp are fast-growing, aggressive, and adaptable fish that are outcompeting native fish species for food and habitat in much of the mid-section of the United States. The huge, hard-headed silver carp also pose a threat to boaters, as the fish can leap out of the water when startled by boat engines, often colliding with people and causing injuries. “Asian carp” is a catchall name for species of silver, bighead, grass, and black carp from Southeast Asia. Voracious filter feeders, Asian carp consume up to 20 percent of their body weight each day in plankton and can grow to more than 100 pounds.

Asian carp were imported to the United States in the 1970s to filter pond water in fish farms in Arkansas and quickly spread across the country. Flooding allowed them to escape and establish reproducing populations in the wild by the early 1980s. Asian carp are swiftly spreading northward up the Illinois River, and are now on the verge of invading the Great Lakes. Once established in an ecosystem they are virtually impossible to eradicate. Adult Asian carp have no natural predators in North America and females lay approximately half a million eggs each time they spawn.

Temperatures in the Great Lakes are well within the fishes’ native climate range. Parts of the Great Lakes, including nutrient-rich bays, tributaries, and other near-shore areas, would offer Asian carp an abundant supply of their preferred food, plankton. Plankton is also favored by most young and many adult native fishes and the voracious carp would likely strip the food web of this fundamental resource. The U.S. Geological Survey has identified 22 rivers in the U.S. portion of the Great Lakes that would provide suitable spawning habitat for Asian carp.

The brown marmorated stink bug, Halyomorpha halys, is native to China, Japan, and surrounding countries. They were first discovered in the United States in Pennsylvania during the late 1990s, but no one knows for certain how they were introduced to North America. Brown marmorated stink bug (BMSB) populations are exploding in the absence of their natural predators, and they are quickly becoming a nuisance to people in their homes and to the agriculture industry.

A big problem with BMSBs so far is the infestation of people’s homes. The bugs begin to come indoors, searching for warm, protected areas when outside temperatures turn cooler in the fall. They don’t reproduce inside the home or cause structural damage, but their namesake odor, noisy flying, and teeming numbers can make the BMSB an extreme nuisance throughout the winter, especially on warmer days when they are more active.

Brown marmorated stink bug

Brown marmorated stink bug

BMSBs feed on host plants by piercing the skin and consuming the juices within; the signs of stink bug feeding appear as “necrotic” or dead spots on the surface. They’ve become a significant agricultural pest in the mid-Atlantic region, and other areas could see similar effects if the BMSB’s range continues to expand. A wide variety of plants are known food sources for BMSBs, including ornamental trees and shrubs; fruit crops like peaches, apples, grapes, and pears; vegetable crops like green beans and asparagus; and soybeans and corn.

Zebra mussels and quagga mussels are virtually identical, both physically and behaviorally. Originally from Eastern Europe, these tiny trespassers were picked up in the ballast water of ocean-going ships and brought to the Great Lakes in the 1980s. They spread dramatically, outcompeting native species for food and habitat, and by 1990, zebra mussels and quagga mussels had infested all of the Great Lakes. Now both quagga mussels and zebra mussels have spread to 29 states by hitching rides on boats moving between the Great Lakes and Mississippi River Basins. Artificial channels like the Chicago Area Waterways System facilitate their spread. These man-made channels act like super-highways and are also a pathway for Asian carp, which are currently spreading towards the Great Lakes.

Zebra mussels and quagga musselsZebra mussels and quagga mussels

Zebra mussels and quagga mussels

The quagga and zebra mussels blanketing the bottom of the Great Lakes filter water as they eat plankton and have succeeded in doubling water clarity during the past decade. Clear water may look nice to us, but the lack of plankton floating in the water means less food for native fish. Clearer water also allows sunlight to penetrate to the lake bottom, creating ideal conditions for algae to grow. In this way, zebra and quagga mussels have promoted the growth and spread of deadly algae blooms.

Zebra and quagga mussels harm native fish populations, ruin beaches and attach to boats, water intake pipes, and other structures, causing the Great Lakes economy billions of dollars a year in damage. They devastate native species by stripping the food web of plankton, which has a cascading effect throughout the ecosystem. Lack of food has caused populations of alewives, salmon, whitefish, and native mussel species to plummet.

In her five-year lifetime, a single quagga or zebra mussel will produce about five million eggs, 100,000 of which reach adulthood. The offspring of a single mussel will in turn produce a total of half a billion adult offspring. There are an estimated 10 trillion quagga and zebra mussels in the Great Lakes today. Once zebra and quagga mussels become established in a water body, they are impossible to fully eradicate. Scientists have not yet found solutions that kills zebra and quagga mussels without also harming other wildlife.

Additional examples:
• Cogongrass is an Asian plant that arrived in the United States as seeds in packing material. It is now spreading through the Southeast, displacing native plants. It provides no food value for native wildlife, and increases the threat of wildfire as it burns hotter and faster than native grasses.
• Feral pigs will eat almost anything, including native birds. They compete with native wildlife for food sources such as acorns. Feral pigs spread diseases, such as brucellosis, to people and livestock. E. coli from their feces was implicated in the E. coli contamination of baby spinach in 2006.
• European green crabs found their way into the San Francisco Bay area in 1989. They outcompete native species for food and habitat and eat huge quantities of native shellfish, threatening commercial fisheries.
• Dutch elm disease (caused by the fungus Ophiostoma ulmi) is transmitted to trees by elm bark beetles. Since 1930, the disease has spread from Ohio through most of the country, killing over half of the elm trees in the northern United States.
• Water hyacinth is a beautiful aquatic plant, introduced to the U.S. from South America as an ornamental. In the wild, it forms dense mats, reducing sunlight for submerged plants and aquatic organisms, crowding out native aquatic plants, and clogging waterways and intake pipes.

Curbing the Spread

One way to curb the spread of invasive species is to plant native plants and remove any invasive plants in your garden. There are many good native plant alternatives to common exotic ornamental plants. In addition, learn to identify invasive species in your area, and report any sightings to your county extension agent or local land manager.

Regularly clean your boots, gear, boat, tires, and any other equipment you use outdoors to remove insects and plant parts that may spread invasive species to new places. When camping, buy firewood near your campsite (within 30 miles) instead of bringing your own from home, and leave any extra for the next campers. Invertebrates and plants can easily hitch a ride on firewood you haul to or from a campsite—you could inadvertently introduce an invasive to a new area.

Native Plants

Native plants have formed symbiotic relationships with native wildlife over thousands of years, and therefore offer the most sustainable habitat. A plant is considered native if it has occurred naturally in a particular region, ecosystem, or habitat without human introduction.

Exotic plants that evolved in other parts of the world or were cultivated by humans into forms that don’t exist in nature do not support wildlife as well as native plants. Occasionally, they can even escape into the wild and become invasive exotics that destroy natural habitat.

Native plants help the environment the most when planted in places that match their growing requirements. They will thrive in the soils, moisture and weather of your region. That means less supplemental watering, which can be wasteful, and pest problems that require toxic chemicals. Native plants also assist in managing rain water runoff and maintain healthy soil as their root systems are deep and keep soil from being compacted.

Native Plant Finder

Bring your garden to life! Enter your zip code to discover the best native plants, attract butterflies and moths, and support birds and other fauna. Native Plant Finder is an indispensable tool, based on the research of Dr. Douglas Tallamy of the University of Delaware and in partnership with the United States Forest Service.Discovering the native plants where you live can also define a unique sense of place and heritage for your garden habitat while preserving the natural history of the flora and fauna of your region.

Rethinking The Invasive Species Paradigm

Where are camels native to? In answering this, you might have four different responses; and they might all be right. Camels are native to:
1. The first place you think of when you hear the word ‘camel’ i.e. the Middle East (Arabian camel)
2. In North America, where they first evolved, lived for tens of millions of years, achieved their greatest diversity, and where they became extinct only recently.
3. In South America, where they retain their greatest diversity (llama, alpaca, vicuña, guanaco) or
4. In Australia, where the world’s only truly wild (not domesticated) dromedaries now occur. (feral dromedary and Bactrian camels).
Depending on your criteria for native; where they evolved, where they’ve been the longest, where they are most numerous, or where they are still a “wild” non-domesticated population, you might answer the question, “Where are camels native to?” differently.

“The discussion about native plants encompasses a remarkable mixture of sound biology, invalid ideas, false extensions, ethical implications, and political usages.”
Steven Jay Gould, evolutionary biologist, writer, Harvard University, Natural History Museum NYC

An Evolutionary Perspective on Strengths, Fallacies, and Confusions in the Concept of Native Plants. S.J. Gould. Arnoldia, Spring 1998. (Quarterly magazine of Arnold Arboretum, Harvard University)

“There is no biological criterion on which to judge a priori the smaller or greater value of one species against that of another.” Lugo, in Biodiversity, E.O. Wilson ed.

You walk through the wood edge of the local park, farm, or neighborhood trail. You see the rampant undergrowth of shrubs with spiny stems and small red berries. Many people have taken an instinctive reaction to these barberry bushes and liken them to invaders on the land that are harming the native species there.

We’ve been hearing for many years about the danger of invasive species. They’re everywhere and causing widespread harm to the environment. And yet, we understand that nature is hugely complex and its hard to grasp all that’s going on with species interactions and besides…everything is changing with all the damage humans are causing to the environment…

The issue of invasive species has permeated our society to where many people fervently believe there are species taking over, causing widespread harm, and that should be eradicated. But many scientists don’t subscribe to these notions but believe that these complex systems are constantly in flux and adapting to the ever present changes. There is no perfection or stability in nature. As they explore the novel ecosystems around us, they ask questions about how they came to be, how they function, and how do they respond to the intense ecosystem changes occurring.

I first came to this issue through my work doing habitat restoration for The Nature Conservancy in the 1990’s. Much of what we did was amazing; replanting forests in flood-prone agricultural land along the Sacramento River in the Central Valley of California. We planted thousands of trees and shrubs. We had a large staff, hundreds of volunteers, and an ecosystem restoration education program. But we also used techniques that continued to disturb the system even as we tried to repair it. We sprayed Roundup with tractor boom sprayers across many acres. We used heavy equipment, brush hogs, and tractors and tilled the soil, increasing the soil disturbance.

I started to have misgivings about the approaches we used and the war we waged with the ecosystem– to save it. I’ve come to believe the process of restoration and land management is as important as the result. It turns out that the ends don’t justify the means. I look at techniques being used in current land management, farming, and landscape work through that lens. In the work I do on residential properties, community land, farms, campuses, and in urban areas, I look to heal the land, reduce the ongoing disturbance, and to reconnect people to the land and their place on it.

There are many questions that need to be asked about invasion biology and “invasive species” (see sidebar). We need to go into our land work, farming, gardening, with an openness to these questions and a desire to reach new understandings.

Inadequate definitions:
There are currently inadequate definitions for many terms used in the native-invasive debate. A simple definition for Native that gets used often is “A plant or animal that lived in a given area before European colonization”. This is a very arbitrary definition. Here’s another. “A plant that is a part of the balance of nature that has developed over hundreds or thousands of years in a particular region or ecosystem. “

These definitions are problematic in their ambiguous use of time frames, locations, and vague terms such as “balance of nature” to determine “belonging”. The nature of species is to move into new areas. This is part of evolution and what creates diverse ecosystems. These not-measurable definitions do not try to measure anything of direct ecological importance. Why is range/geography in and of itself ecologically essential? Why is a time period of being in a place a definition of nativeness?

So the question arises: which period of time are we talking about as the basis for the snapshot which defines nativity? Why should we choose one time period over another for that snapshot? Shouldn’t the definition of “native” apply to all species in all ecosystems if the concept or definition is to be valid, and not apply only to the unique circumstances of the Western hemisphere and its history of European arrival 500 years ago? And how do we know what that species range is or was in 1492, or 1500, or 1600? We have a better idea what ranges were in 1950, when E. Lucy Braun published her findings of the first, most comprehensive look at the plant communities of the eastern half of North America. But that is far too late a date, isn’t it, by the definition of native now in use? Are the range maps we refer to compiled using multiple time periods and multiple sources? I have looked at many range maps, and there has never been a date given for when the species was in that range, even though we know that species move far and wide in response to past climate changes.

Some of those movements continue today in response to the melting of the glaciers 15,000 years ago, not to mention our current climate changes. In his excellent book Where Do Camels Belong? Ken Thompson uses the evolution of camels as a query about defining nativeness.

Inflammatory Rhetoric

The media has taken hold of the invasive species issue and run with it. There are many books, articles, fliers, fact sheets, websites, speakers, conferences, journal articles espousing the dangers of invasive species and how to get rid of them. Words like “taking over”, “biological pollution”, “invaders”, “planet of weeds” and “overrunning” are used to describe these newcomer species and what is happening. There is the use of fear to motivate action. A “culture of fear” has developed that even leads people to fear going outside, lest they come into contact with a dangerous invasive species.

Short Time Frames

Ecosystems develop and evolve over hundreds and thousands of years. Trees can live for hundreds of years. Our human time frame of years, decades, and a human lifespan is often too short to really grasp the long timelines of natural systems. Researchers trying to understand invasive species often do studies based on a graduate program or funding cycle of months to several years.

The field of Biogeography is the study of species and ecosystems changes through geologic time and geographic space. Species ranges are a tool to understand where species are located in a given time. A range map is often used to define whether it is native or not. But without a reference to time the idea of range is useless. Species ranges change over very short time frames; sometimes thousands of years and sometimes over hundreds or tens of years. Should we presume that a given species’ native range is that of where it was when European settlers came and no more and no less forevermore? Could any ecologist stand by this concept where species ranges don’t change over time?

Since the retreat of the most recent glacier in New England, about 15,000 years ago, there have been huge changes to the regional climate as species began colonizing this raw, scraped land. By 10,000 years ago temperatures were close to todays and by 8,000 and 5,000 years ago the climate was even warmer. The northeast region was tundra and boreal forest for thousands of years after the glacial maximum. Pollen studies have revealed an intricate process of plant migration into the region that has changed our understanding of plant community timelines and formation. It is no longer believed (by many ecologists) that plants move as whole ecologies, tightly knit together. Instead organisms migrate at different rates using different routes. Spruce (Picea spp.) were in the region 12,000 years ago. 3,000 years later hardwood forests were assembling with oak, maple, elm, and other species. Hickory arrived only 5,000 years ago and the latecomer Chestnut arrived to New England only 2,000 years ago and came to dominate an already assembled ecosystem. 5,000 years ago hemlock (Tsuga Canadensis) experienced a sudden decline in abundance in the region, possibly from a disease outbreak. In 2,000 years it recovered its previous abundance.

Ecological Fitting vs. Coevolution

Many ecologists learned in school that when two species are in cooperation, sharing or utilizing each other in some way that this is a form of “mutualism” or co-evolution; i.e. these species have evolved together over time to develop a connection. An insect utilizing a specific flower, or a fungi-plant interaction are examples of this kind of co-evolved behavior. And thus many people have come to see the ecosystem as a tightly fitting interconnected and interdependent web. The result of this idea is believing that ecosystems are set combinations of specific species and thus brittle and liable to break apart when disturbed.

It turns out that though there are some co-evolved and tightly dependent relations in nature, in the last decades ecologists and researchers have begun to understand ecosystems as much more fluid and adaptable. One researcher who pioneered this understanding is Daniel Jantzen who coined the term “ecological fitting” in 1980, for “the process whereby organisms colonize and persist in novel environments, use novel resources or form novel associations with other species as a result of the suites of traits that they carry at the time they encounter the novel condition.” In this view, nature is a fluid system constantly changing, mixing, and adapting. Species come. Species go. Often in largely random ways over short and long periods of time.

Janzen came to his idea of ecological fitting while working in Santa Rosa National Park, Guanacaste province, Costa Rica. He observed that the Guanacaste tree, the national tree of CR and vitally important to the tropical drylands, was not reproducing. The seeds would pile up and there was limited reproduction due to the lack of seed dispersers; herbivores that could eat and spread the seed. The previous dispersers were the ground sloths, camels, ancient horses and others that disappeared during the megafauna dieoff approximately 10,000-15,000 years ago (probably from climate change, human overkill- or a combination of both). Janzen surmised that the ecosystem lacked a seed dispersal herbivore to replace the lost megafauna. His solution was to reintroduce the modern horse into Santa Rosa National Park, a controversial approach in conservation circles where purity of species introductions is paramount. Bringing in a domesticated and non-native species (though originally evolved on the continent) was ecological heresy. It turns out that the European horse was a perfect surrogate for eating the fruit pulp without chewing the seeds and depositing them on the landscape where they could establish.

In Janzen and other researchers’ and conservationists’ view, species combinations are constantly under change, there’s no fixed formula. Across a landscape there’s often a gradation of species mix with no break between combinations. The idea of a climax forest or ecosystem has been debunked as it’s become clear there’s no settled arrangement, often there’s a large dose of chance of which seedling is there when a storm takes down a large tree, or the seed mix in the soil after a fire comes through.

Relatedly, the idea of ecosystems as complete and full is just as erroneous. New species often find space within an ecosystem and there is no “one species in—one species out” kind of trade off. Study of island biogeography and ecosystem dynamics has shown that many more species can arrive and find niches without the loss of other species.

Novel ecosystems

Seed dispersers, needed to help these seeds reproduce

Seed dispersers, needed to help these Guanacaste tree seeds reproduce, had disappeared until the horse was introduced.

These new combinations of species have been given the name novel ecosystems. They are a hallmark of the Anthropocene; ecosystems altered in some way by humans and they now cover as much as a third of the planet, In nature there is no judgement of the players as good or bad, belonging or not…everyone finds their way, their place, or moves on. The study of novel ecosystems is increasing as scientists try to understand these new ecologies and how they adapt and evolve. There is growing evidence that the increase in new species combinations will lead to a burst in evolution, hybridization, and speciation. It is a brave new world that we’re headed into.

“Sure, species move and the ecosystem is changing… but some super aggressive species are “taking over”, pushing out other species, and causing a lot of damage to the environment”

And here we get to the crux of the issue. We don’t mind some of the plants and animals coming in, but its those few that are really causing the problem; bittersweet, Japanese knotweed, mile-a minute vine, barberry, black locust, and the list goes on. The claim is harm and taking over by these newcomers, but is there evidence? Is there more than the anecdotal idea we get when we see a species growing aggressively and expanding into our yard, woodland, or field? Is a species causing harm by this expansive growth? Is it causing harm by existing in a place and taking up space?

Idea of Harm

Much of the harm that many people experience is a very subjective and arbitrary one. Where people have decided they don’t like a plant or animal, “it’s invasive” is a reason to dislike and remove it. Its mere presence is seen as causing harm. Wild nature, out of our control, is not something modern human society has allowed. Sometimes it doesn’t even need to be a newly arrived species. Poison ivy, grapes, sumac, dandelions, and others can be considered invasive as well. A sad offshoot of this is that children and many people see nature as dangerous; a place where there are bad plants and animals hurting the environment and they may hurt you or your children. We are moving into a period where people are losing their nature connection, and casting some nature as good, and some nature as bad is just feeding this nature disconnect.

One commonly used statistic of invasive species harm is “invasive species are the 2nd leading cause of species extinctions”. This is a factoid from a scientific paper by David Wilcove “Quantifying Threats to Imperiled Species in the United States” printed in the journal BioScience in 1998. This widely cited paper was in fact based on anecdotal and observational accounts by land managers, using limited data. It also included Hawaii, which is a very distinct situation, being an island with species evolved in isolation and then centuries of introductions by humans. The authors expressed the limitations of the data and yet the idea that “invasive species are the 2nd leading cause of extinctions” has gained a life of its own and is repeated often without reference to the source or limitations. A Canadian assessment in 2006 found that invasive species were the least of all factors considered. The biggest factor? Disturbance and removal of habitat by humans.

Harm can also be quantified monetarily. One widely quoted amount comes from a study done by David Pimental, a Cornell professor, in a paper published in 2005. He calculated that invasive species cost the US $120 billion dollars a year. This number is large enough to move federal bureaucracies and research institutions to fund removal campaigns, research, and a massive education campaign against these invaders. Unfortunately when one looks closely at the calculations to get to $120 billion per year it stretches reason and heads quickly towards the absurd and misleading. It includes:
– Crop losses in agriculture (mostly nonnative crops) from weeds ($24 billion/yr).
– Herbicides used in U.S. agriculture ($4 billion/yr).
– Control of species in lawns, gardens and golf courses including pesticides and herbicide use. ($1.5 billion/yr)
– Forage losses and “weed” control on overgrazed range and pasture ($6 billion/yr).
– Cost of domestic cats in damage to U.S. bird population. ($17 billion/yr).

Many of the costs are to industry, including the cost to companies to keep waste outlet pipes heading into waterbodies from getting clogged by zebra mussels. The benefits of these newcomer species aren’t part of the calculation. For instance those zebra mussels clogging the industrial pipes also have been cleaning the Great Lakes and other waterways of human-caused pollution, leading to cleaned up waters (they are filter feeders) and a return of many sport fishing species and commensurate return in the sport fisheries industry.

Scientific literature — what are scientists saying?
The conservation and research community is slowly coming around to question the dominant ideas around invasive species. There are reviews looking at bias in scientific studies of invasives, studies of the “real” impact of invasives, and studies of the benefits of these new arrivals. One particular thread is to tease apart whether invasives are the “drivers” or “passengers” of change in ecosystems. Several of these studies have identified, among the complex interactions going on, that invasives often ride in on the changes in ecosystems that we humans have initiated. Its not surprising, but for several decades now, scientists have worked from the presumption of harm, and research has looked to confirm that and focus on methods to remove species.

Reassessing Specific Cases/Species

Tamarisk in flower in April in Galacia, Spain

Tamarisk in flower in April in Galacia, Spain

Its coming to light that many of the species accused of egregious harm are guiltless and even are bring benefits to landscapes they are in.

A classic case of this is tamarisk (Tamarix spp.), a shrub introduced into arid southeastern landscapes in the 19th century. They were initially welcomed as an ornamental, and a drought-resistant shade tree. In the 1930’s as drought swept through Arizona, Central New Mexico, and West Texas and they were branded as “water thieves” and then after WWII as nonnative invaders salting the water. For 70 years they were the object of an intensive removal campaign using bulldozers, chains, herbicides at the cost of tens of millions of public dollars. In the last few years ecologists have found that they utilize water at the same rate as other riparian species and do not add additional salt. (Stromberg, 2009) They are also the preferential nesting habitat of the endangered Southwestern willow flycatcher. This species is surviving and thriving under the vastly changed water regimes in the altered southwestern landscapes. Shouldn’t we recognize that tamarisk has a place as part of restoring those places?

A nitrogen fixer, this black locust tree has wood which is a homesteader’s dream.
Its sale is also outlawed in some places.

Closer to home, black locust (Robinia pseudoacacia) is accused of being a non-native invader. This suckering, nitrogen-fixing tree was certainly here in the region before the last glaciation pushed it out, and was moving steadily northward. Range maps from mid 20th century show it as being in present day Pennsylvania, but unfortunately not within the borders of Massachusetts and so suspect as a problem newcomer. The label non-native invader comes from its propensity, primarily in the sandy soils of Southeast MA and Cape Cod, to spread readily, utilizing its ability to fix nitrogen to colonize the depleted soils; depleted from the land clearing, grazing, and farming activities of people since the earlier human colonists came some 500 years ago. Black locust trees repair the land and bring back fertility through their tenacious growth and nitrogen fixation. They are one of the most resilient and multi-functional trees in the region, providing rot resistant post wood, pollinator support, fodder, high btu firewood etc — but they are outlawed for sale or distribution in Massachusetts. Earlier settlers through much of the last century relied on these regional resources. The USDA Silvics Manual Vol 2 (1990) outlines the many current and historic uses for black locust: “It is used for fence posts, mine timbers, poles, railroad ties, insulator pins, ship timber, wooden ship construction, boxes, crates, pegs, stakes, and novelties…. Black locust is widely planted…for erosion control, reclamation of drastically disturbed sites, windbreaks, nurse crops, amelioration of sites, honey production, and ornamental use.” Society has changed and so has our preferences for the plants around us, but this tree is certainly high on my “best trees” list.

Looking Ahead

What do we do? How can we change our relationship with the world around us and not be drawn into fighting nature itself? In the work I do with landowners we look for ways to meet their goals while restoring and regenerating the land. Each person is different and can try out different practices like tree planting, selective thinning in woodlands, changes to mowing management and rebuilding soil with compost, microbial inoculation, and encouraging pollinator support plants.

• Incorporate change- Don’t stop the flow
Our work on the land needs to work with ecological processes. In the martial art aikido, incoming energy is transformed and redirected, not blocked. The work we do must be earth aikido. There is a temptation to begin fighting the species that arrive with herbicides or pesticides and causing further disturbance and disruption.

Understand the current patterns and flows on the land and adapt your practices to be more in line with that. i.e. change your vegetation management (mowing, weeding, clearing), water and soil management.

• Learn to Live with Them
These new species, naturalized and in many cases already here for centuries, aren’t leaving. We can learn to live with them. When taking a walk or working on the land, notice your reaction to plants; do you feel anger towards these new arrivals? What is coming up inside you like concern for the environment, or concern for the future? And how are these plants and animals part of that concern? How can we transition from anger and pain to healing and forgiveness?

These new combinations of species, our “novel ecosystems,” are responding to ecosystems changes. Long-standing species are behaving differently with new conditions. Lets explore them. Celebrate the new connections being made.

• Understand the context of where you’re working
Wherever we live and work we need to deeply investigate the history of the land. We need to understand past disturbances, like fire or storm events, successional changes, species arrival, changes to hydrology, terrain and air flows. Human changes are often intertwined with the ecological trajectory, particularly the disturbance history. What kind of changes have humans made and how has the land been managed, altered, or disrupted?

Here in New England, there have been centuries of human disturbance. Layers of land clearing, acid rain, fire suppression, forestry, grazing, farming, and more recently development and urbanization have left an utterly changed ecosystem. On a landscape scale, the activities that have left places degraded can sometimes be used to reverse the damage. For instance overgrazed land might be restored by intensive mob grazing. Thinning woods, managing brush, and tree planting can reverse high grading or clear cut management.

More Plants with Multiple Values

Many “invasive species” are actually super beneficial for habitat, ecosystem functions, and food or medicine. Here are two examples:
Autumn Olive, Russian Olive, Goumi (Eleagnus spp.)
• Introduced for soil stabilization, ornamental, wildlife value.
• Fixes nitrogen, hardy, drought tolerant, few pests/diseases, disturbance adapted.
• Used to reclaim strip-mined land, wildlife habitat.
• Delectable fruit high in lycopenes (cancer reducing compounds: 6-20x the levels in tomatoes; Fordham, 2001). High in vitamins A, C, E, flavonoids, and essential fatty acids.

Japanese Knotweed (Polygonum cuspidatum)
• Introduced as an ornamental in late 1800’s.
• 2,000 year medicinal history in Asia.
• Edible shoots, high in resveratrol, anti-Lyme, anti-cancer, anti-bacterial compounds.
(Buhner, Healing Lyme, 2005)

“ Man (sic) is part of nature, and his war against nature is, inevitably, a war against himself.”
Rachel Carson, Silent Spring, 1962

Reducing the ongoing disturbance should be a priority.

• Urban environments — altered and not going back
Urbanized environments have special conditions to be considered. These environments have long histories of change with altered hydrology, soils, and air. Nothing is like it was in the past and the idea of bringing it back to some past condition is a nostalgic notion and unrealistic. A vacant lot in downtown Lowell, MA will not become the floodplain forest that it once was several hundred years ago before the Merrimack River was channeled and urbanized. What is the best use of the urban Lowell land? What are the ecological functions it can serve where it is, now? How might it serve the residents of the neighborhood and reduce their demands for food, water or other goods from far away? Put the lens of an earth healer and food grower on and a whole world of possibility opens up.

• A sensible policy on native and naturalized species
We need a sensible policy on naturalized species that allows us to pull back from trying to control everywhere. It may be part “learn to live with them” and it may be selective management and removal, recognizing there are specific vulnerable habitats and species that need our intervention, allowing some areas to go through succession, as messy as it looks, and focusing on stabilizing and reducing disturbance.

• Protect and restore diverse, rare, and sensitive ecosystems. Refugia!
There are places that need to be protected and carefully managed. These are locations with rare species, specialized and unique habitats, genetic diversity hotspots, and places where research and conservation is ongoing.

• Create and expand habitat corridors
Connect isolated habitats through corridors that allow dispersal and movement of species. This is essential as climate change requires movement of plants and animals into new areas.

• Restore ecological function
Focus on function and not the name or original location of a species. In this time of stressed ecosystems we need species that are resilient and adaptable. We can assist in development of these resilient and productive ecosystems and communities. Utilize deep sustainability, regenerative approaches, and permaculture design.

• Human-assisted species dispersal in response to habitat loss and climate change
We will need to be active participants in helping species that have become isolated or whose movement can’t possibly keep up with the ecosystem changes we’re dealing with.

In 2010 my wife Kemper and my young son visited the California restoration project that we worked on in the early 1990’s. The forests had grown tall, deer watched us from the brush and woodlands we planted. The Sacramento River flowing nearby had breached its banks and flooded through the fields, cutting side channels and depositing woody debris. It was an affirmation that we can get on the right side of nature and become part of the solution. My son walked those fields with us and, I hope, saw a vision for the future where we can help repair the world around us.

It would be far better to teach people about the rich biodiversity and ecology around them, and to foster an appreciation for all living things, than to hide behind science while pushing pest control agendas that contribute to more loss of habitat and declining biodiversity.

And surely the most insidious and destructive outcome to be avoided is the fostering of human alienation with nature, or a feeling that we are surrounded by an alien and therefore, unnatural, environment.

Fostering a worldview that some species are good while others are bad sets the stage for a nihilistic society that can never be at ease in, or nurtured by, the natural world.
Vivian Parker, California Indian Basketweaver’s Association (2002)

Jono Neiger has thirty years experience in conservation, restoration, land stewardship, permaculture, agroforestry and landscape design and planning. Jono was the Land Steward at Lost Valley Educational Center, Oregon, Restoration Ecologist with the Nature Conservancy of California, and Lost Creek Watershed Council Founder and Coordinator. He was faculty at the Conway School of Landscape Design, founding board president of the Permaculture Association of the Northeast, and is a founding partner of the Regenerative Design Group in Greenfield, Massachusetts. He operates Big River Chestnuts, an emerging chestnut agro-forestry in Sunderland, MA.

Creating Native Plant Corridors for Pollinators

photos by Jean English
reprinted with permission from the Maine Organic Farmer and Gardener

Juniper berries


Native plant corridors attract pollinators and wildlife to your farm by stretching across your property to connect your piece of native habitat to nearby meadows, wetlands or woodlands. This creates a much larger area for native pollinators to forage, raise young and migrate. Corridors may run along a road, between fields, in a swale or on the edge of a forest, connecting habitats off the property and returning native plants to the parts of the farm not suitable for traditional crops.

This article describes two approaches to creating native habitat corridors: changing mowing habits to favor native species, and planting woody and herbaceous combinations to increase native plant diversity on the farm.

Populations of all native species are in decline across the state. Our human footprint is taking its toll on wild creatures, including pollinators such as bees and butterflies that are so important on the farm for crop pollination. Native plant species each share an evolutionary history with indigenous insects, birds, reptiles, mammals, bacteria and fungi. When native plants are gone, many of these creatures go too, leading to a collapse of ecosystem function. Farmers benefit from the services provided by a healthy ecosystem, such as groundwater recharge; clean surface streams and ponds; pollination; a diversity of birds, spiders and amphibians to eat many insects including crop pests; and beneficial soil fungi and bacteria. Fortunately, when native plants are reintroduced into a landscape, many of these other creatures return.

As farmers and landowners, we can bring native plants, and the attendant diversity, back into the Maine landscape in a way that works with a farmer’s busy schedule. Many native plants thrive in dry, wet and shady areas that are poor sites for traditional farm crops.



Mowing Regime to Create a Pollinator Corridor
The easiest way to promote a pollination corridor is by changing your mowing regime. Along with forest clear-cutting and urban sprawl, mowing habits impact insect pollinators, birds and other fauna tremendously. In New England, most landowners and municipalities mow their roadsides and fields in the middle of the growing season. For hay harvesting, this makes sense, since the hay crop is at its prime. However, this is not good timing for native plant flowering and seed ripening or for the myriad creatures that depend on this critical part of the native plant life cycle. Pollinating insects depend on these native plants for some parts of their life cycle; for instance larval Monarch butterflies eat only milkweed foliage. In the months of May to October, insect-based pollination is at its height, and a healthy nearby population of these pollinators on the farm promotes effective crop pollination.

An easy way to support the life cycle of these plants and pollinators is to delay mowing until the end of the season – late October or early November in Maine. In fact, many meadow areas need only be mown every few years to keep the forest from returning.

Native pollinators such as bees and butterflies need more than flower nectar to survive. For much of the year, they are either hidden in a nest or cocoon or are in a different stage of life (think caterpillar before turning into a butterfly). Pollinators need native plants to deposit their eggs, feed their larvae (many of which eat only native vegetation) and for overwintering habitat. Leaves, bark on trees and shrubs, dead woody twigs, dried stems, rotting logs, branches, and even bare, undisturbed sandy or gravelly ground are all important habitat. When you mow an area, much of this year-round habitat is removed. To provide important food and overwintering habitat for fauna all year, divide your corridor into mowing zones. Each year choose a section of the pollination corridor to be the overwintering habitat and leave it un-mown. The rest can be mowed at the end of the season after the flowers have gone to seed. This simple method of changing mowing habits will provide an effective, robust pollinator habitat.

Planting a Hedgerow of Shrubs and Wildflowers

Liatris and a Monarch butterfly

The second method involves actively reintroducing native woody and perennial plants to create year-round habitat for many of our most important insect pollinators, birds and other creatures. These plants can be added to an area that is now lawn, is not mowed or is located on the shady side of a field that borders a woodland. Much of the work can be done in late fall and early spring when the ground is too wet for planting annual crops. Many of these native plants even produce a harvestable crop.

A couple of months to a year before you intend to plant, lay down cardboard or newspaper with a heavy layer of mulch on top. Mulch can be straw, spoiled hay, bark mulch, aged wood chips, leaves, seaweed or any organic matter that is available at little or no cost. In a few months, the grasses and other vegetation under the mulch should be smothered and decayed. This is an effective way to get a weed-free planting area without tilling the soil. A site mulched in late September can then be planted easily the following spring or even a year later.

Bare-root shrubs, trees and perennial species (see sources below) can be planted by slicing through the mulch with a spade. For directly seeding wildflowers, a strip of weed-free organic mulch (as is available from Coast of Maine products) makes a nice seedbed. This can be laid on top of the previous mulch before planting.

A more efficient method for seeding native shrubs and wildflowers is to plant the seeds into nursery beds or pots and transplant a year or two later. (See the bibliography for native seed propagation information). I recommend choosing a minimum of 10 species for your corridor to ensure a diversity of bloom times and vegetation options for the fauna. Note the bloom times to ensure plenty of nectar for pollinators throughout the season. The following native corridor species lists should provide plenty of choices for your pollinator corridor.


Plants for medium soil for part of full sun

Black-eyed Susan – Rudbeckia hirta, R. triloba
Blue vervain – Verbena hastata
Golden Alexander – Zizia aurea
Shadberry – Amelanchier canadensis, A. laevis
Chokeberry – Aronia arbutifolia, A. melanocarpa
Summersweet – Clethra alnifolia
Shrub dogwood – Cornus alternifolia, C. amomum, C. racemosa, C. sericea
Hazelnut – Corylus americana, C. cornuta
Hawthorn – Crataegus spp.
Shrubby St. John’s wort – Hypericum prolificum
Winterberry – Ilex verticillata
Cinquefoil – Potentilla fruticosa
Arborvitae – Thuja occidentalis
Viburnum – Viburnum dentatum, V. lentago, V. nudum, V. trilobum, V. prunifolium


Canada anemone – Anemone canadensis
Indian potato – Apios americana
Aster – Doellingeria umbellata, Symphyotrichum novae-angliae
Wild geranium – Geranium maculatum
Pink butterflyweed – Aslepias incarnata
Milkweed – Asclepias syriaca
Blazingstar – Liatris ligulistylis
Penstemon – Penstemon digitalis

Plants for dry sandy or gravelly soil in part or full sun

Chokeberry – Aronia arbutifolia, A. melanocarpa
New Jersey tea – Ceanothus americanus
Gray dogwood – Cornus racemosa
Hazelnut – Corylus americana, C. cornuta
Yellow bush honeysuckle – Diervilla lonicera
Shrubby St. John’s wort – Hypericum prolificum
Juniper – Juniperus spp.
Bayberry – Myrica pensylvanica
Beach plum – Prunus maritima
Sumac – Rhus typhina
Wild rose – Rosa virginiana
Steeplebush – Spirea tomentosa
Viburnum – Viburnum nudum, V. prunifolium

Clethra anifolia

Butterfly weed – Aesclepias tuberosa
Field pussytoes – Antennaria neglecta
Aster – Aster concolor, A. ericoides
Wild strawberry – Fragaria virginiana
Liatris – Liatris squariosa
Lupine – Lupinus perennis
Black-eyed Susan – Rudbeckia hirta
Goldenrod – Solidago sempervirens

Plants for medium to dry and highly acidic soil in sun to part shade

Sweet fern – Comptonia peregrina
Huckleberry – Gaylussacia baccata
Bayberry – Myrica pensylvanica
Bush honeysuckle – Diervilla lonicera
Red elderberry – Sambucus pubens
Lowbush blueberry – Vaccinium angustifolium

Bunchberry – Cornus canadensis
Lupine – Lupinus perennis
Violets – Viola pedata

Plants for wet soils in part or full sun


Joe-Pye Weed

Buttonbush – Cephalanthus occidentalis
Summersweet – Clethra alnifolia
Dogwood – Cornus amomum, C. racemosa and C. sericea
Witch hazel – Hamamelis virginiana
Spicebush – Lindera benzoin
Winterberry – Ilex verticillata
Sweetgale – Myrica gale
Mountain holly – Nemopanthus mucronatus
Rhodora – Rhododendron canadense
Steeplebush – Spirea tomentosa
Pussy willow – Salix discolor
Elderberry – Sambucus canadensis
Highbush blueberry – Vaccinium corymbosum
Viburnum – Viburnum dentatum, V .nudum, V. trilobum

Pink butterflyweed – Aesclepias incarnata
Marsh marigold – Caltha palustrus
Turtlehead – Chelone glabra
Joe-pye weed – Eutrochium maculatum, E. dubium, E. fistulosum
Boneset – Eupatorium perfoliatum
Blue flag iris – Iris versicolor
Lobelia – Lobelia cardinalis, L. siphilitica
Canada lily – Lilium canadensis
Golden ragweed – Packera aureus
Aster – Symphyotrichum novai-belgii
Blue vervain – Verbena hastate

Plants for a deciduous woodland corridor with part to full shade (planted on the north, east or west side of deciduous trees)


Ostrich fern

Mountain maple – Acer spicatum
Pagoda dogwood – Cornus alternifolia
Witch hazel – Hamamelis virginiana
Spicebush – Lindera benzoin
Purple flowering raspberry – Rubus odoratus
Blueberry – Vaccinium spp.
Viburnum – Viburnum alnifolium, V. acerfolilum, V. dentatum, V. nudum

Wild leek – Allium tricoccum
Wood asters – Eurybia macrophyllus, Symphyotrichum cordifolia
Blue cohosh – Caulophyllum thalictroides
Black cohosh – Cimicifuga racemosa
Goldenseal – Hydrastis canadensis
Ostrich fern – Matteuccia struthiopteris
Penstemon – Penstemon digitalis
Solomon’s seal – Polygonatum biflorum
False Solomon’s seal – Smilacena racemosa
Ginseng – Panax quinqefolia
Woodland goldenrod – Solidago caesia, S. flexicaulis
Wood violet – Viola novae angliae

Plants for part to full shade with conifers to the north, east or west side


Solomon's seal

Solomon’s seal

Mountain maple – Acer spicatum
Yellow bush honeysuckle – Diervilla lonicera
Huckleberry – Gaylussacia baccata
Red elderberry – Sambucus pubens
Lowbush blueberry – Vaccinium angustifolium
Viburnum – Viburnum cassinoides

Wood aster – Eurybia macrophylla, Symphyotrichum cordifolium
Canada mayflower – Maianthemum canadense
Bunchberry – Cornus canadensis
Wood sunflower – Helianthus divaricate
Woodland goldenrod – Solidago caesia, S. flexicaulis

Nursery Sources

Fedco Trees
Nasomi Farms: the nursery of the New England Wildflower Society
Native Haunts, Alfred, Maine
Prairie Moon Nursery
St. Lawrence Nursery
Wild Seed Project – seeds of Maine native plants Bibliography
“Attracting Native Pollinators,” by the Xerces Society
“Bringing Nature Home,” by Douglas Tallamy
“Farming with Native Beneficial Insects,” by the Xerces Society
“Growing and Propagating Wildflowers,” by William Cullina
“Native Trees, Shrubs and Vines,” by William Cullina
New England Wildflower Society plant ID website

About the author: Heather McCargo is executive director of Wild Seed Project, a 50(c)(3) nonprofit dedicated to returning native plants to the Maine landscape. From 1990-1995 she was the plant propagator at the New England Wildflower Society’s Garden in the Woods. She has written and lectured widely on native plant propagation and horticulture. Contact her at For further information, see

The Eternal Cycle of Succession

When I was asked to write an article on “invasive species”, my first reaction was to sigh and roll my eyes. (Notice that I’ve already placed the term “invasive species” in quotes… sigh!)
“I’m being baited”, I thought to myself. “Someone has a political agenda and is trying to get me to make someone angry”.

My inquisitor tried to reassure me that “No!” they did NOT have such an intention, but because of my ecological perspective and my 25+ years of experience in converting ecologically degraded sites (clear cuts, agricultural fields, sand mines, etc.) into ecologically designed food-producing systems, I “might have a perspective that others might find useful.”

Regardless as to which is more true, here we are. I agreed to write this article!


Fighting Bamboo

Fighting Bamboo

“Invasive species” have been the cause of much alarm within my lifetime and have become almost universally known among folks who are conservation minded and “environmentally aware.” Images galore can be found of Kudzu “covering everything” in the south, oriental bittersweet vines “strangling the canopies” of entire forests in Connecticut, bamboo “taking over” highway medians in the mid-Atlantic states or, quite memorable to me, seeing Autumn Olive for miles and miles along highways and popping up wherever there was a patch of un-mowed pasture in central Massachusetts where I grew up. If you’re reading this article you are familiar with some kind of organism that is considered “invasive”.

“Invasive species”, we’re told, are causing untold billions of dollars in damages, are decimating native species, are plaguing private and public lands alike, are simplifying ecologies and leading us all in the direction of becoming a planet of “weeds”. Pretty soon they’ll probably join forces with the zombies and obliterate civilization as we know it.

I don’t disagree that highly competitive, rapidly colonizing, non-native plants have observable effects within the natural world around us. I don’t doubt that “invasive” non-natives like Tatarian honeysuckle (Lonicera tatarica ) have caused local extinctions of spring ephemerals in many semi-shaded woodlands. I have seen with my own eyes the damage that insects such as Gypsy Moth, the Emerald Ash Borer, and diseases such as chestnut blight (Cryphonectria parasitica) have caused within our natural world. These effects are REAL and they are changing what nature itself actually IS.

I cannot undo the pain and anger of the losses that I see all around me on a daily basis, but my ability to cope with reality is helped by an understanding that is grounded in observable reality, the study of nature: ecology. This understanding also informs my actions so that when I get up to work in this world, I can limit the number of windmills I joust. An ecological understanding frees up my time and emotional energies so that I can be more effective at what I do. (creating perennial food ecosystems on degraded lands wherever I go!) Hopefully you can find some of what I share to be helpful as well.

One of the most important ecological principles worth knowing about, is the principle of succession. Natural succession, “old field succession” and ecological succession are some other words used for it. It can be summarized simply by understanding that ALL THINGS CHANGE. Period. Always. Your opinion doesn’t matter.

When you look out your back door, the fields or forests, lawns or gardens, or even highways that you see are all somewhere within the cycles of succession. Your own garden on a daily basis begins to sprout “weeds”. These weeds can grow so fast that they rob your crops of water and nutrients, your yields suffer and you may eventually abandon the whole thing. It doesn’t end there, though… The weeds in your abandoned garden, the rank, fast growing mostly annual weeds, don’t quite take up all of the possible niches that could be colonized by life, and some other sort of plant finds a toehold. The first wave of weeds that caused you to abandon your carrots, have changed the conditions. Perhaps they have added more carbon to the soil, or perhaps they have accumulated a particular nutrient from a different soil strata than your carrots, and they have changed the original site conditions to something different. These new site conditions provide opportunities for plants other than what is currently growing there and when seeds or other plant propagules (rhizomes, roots, bulblets, etc) blow in, fall in, are brought in by animals, etc, the plant community changes.

Your garden gives way to annual weeds, the annuals and biennials give way to perennials, especially grasses. Through the years the “old field” that was once your carrot patch, gets invaded by brambles and other thorny shrubs. The raspberries and blackberry canes invading that field even look like the arching backs of sea-serpents as they loop their way into the open areas. Within this increasingly impenetrable thorny thicket you’ll see some trees beginning to raise their heads above the mess. Many of the first trees you’ll see were once fruits or nuts dropped by some squabbling jays, or stashed by a squirrel. If the local pines had a good cone crop the year you abandoned garden, you may see a pure thicket of them growing shoulder-to-shoulder and excluding other plants. Eventually the shade beneath the tree and shrub canopy becomes so great that the grasses can no longer survive.

The conditions have changed. As the trees grow in diameter and height they begin to compete with one another for water, light and nutrients. A large percentage of them begin to die along with the shrub layer which becomes more and more sparse. Your original garden is no longer recognizable. You can now walk beneath the shady canopy on a forest floor littered with leaves and needles. It has become the typical New England “forests” that you can see all around. It may live a LONG TIME!, hundreds or perhaps thousands of years. It is not staying still, however. The “young” forest of 100-year-old oaks, hickories, cherries and pines are gradually being “under grown” with shade tolerant basswood, sugar maple, hemlock and beech. Given enough time, all but the grandest of old pines or ancient oaks will be within a matrix of shade tolerant trees.

Tatarian honeysuckle

Tatarian honeysuckle

Eventually these old, large trees die and leave a gap in the canopy. Perhaps a hurricane blows through and knocks down 100 acres of this forest. In both cases, the site has been “disturbed”. A site that was a sunny vegetable garden with herbs and flowers and hummingbirds, changed through time to become an old-growth forest which then blew down in the wind and has become a sunny spot once again with exposed soil, not from a plow or roto-tiller, but where massive root systems have been pulled from the ground. Succession has been set back in ecological time to a previous phase. The land and what you see outside your door today is not a THING, but merely one scene, one phase within the timeless drama of succession. Hurricanes, ice storms, loggers, developers, fire, grazing and trampling, the plow, the rototiller and the hoe all cause ecological “disturbances” that change the site conditions providing opportunities for other species to move in.

Your site is the stage for this drama. The bedrock and the soil that it becomes, the available moisture, summer warmth and winter cold, the climate (stable or changing, it doesn’t really matter) is the context within which this play will take place. Species that will survive in a particular site or region as it ACTUALLY IS, are the actors on that stage. The changing appearance of the landscape, in fact the entire PLANET is the play itself. Shakespeare could never have written anything so complex and beautiful.

We participate in this play whether we are conscious of it or not. Plant populations and the creatures that depend upon them, change as the conditions change. Species come and species go. The piece of earth outside your door, the drama that you see today is NOT the same as it was 50 years ago. It is not the same as it was 200 years ago. It is not the same as when the Europeans first arrived, or when the First Nations first arrived, or when it was covered with ice, or when mastodons browsed in New York, or when that dinosaur first tempted Eve to eat from that particular tree. This drama has been going on for a LONG time.

What does this have to do with “invasive species”? Well, everything! let’s use Garlic Mustard as an example…

My adventures in SW Wisconsin began in 1995 when I moved to a farm property with the intention of converting it from a row-crops (corn, peas, oats, and hay… soybeans had not really invaded yet) based dairy farm into a perennial, food-producing ecosystem. I had done my research, and had learned that upon European arrival, and for at least the previous 13,000 years or so (based on archeological evidence and based on the biological legacies of surviving plant species) that this place was what could be categorized as Oak Savanna. Roughly the same “actors” are on stage here in WI as there are in the Northeast except that here less rain falls, hurricanes don’t play as much of a disturbance role, fire plays a BIGGER role, as did grazing from large herds of herbivores. If you were to imagine your carrot patch that had become an “old field” that was punctuated by oaks and hickories with a brushy understory, that is what this place had been for who knows how many millennia. Before the canopy could close and shade out the grass, a fire would come through and re-set the shrubland.

Since Oak Savanna was what it WAS, that was what I chose as my ecological model for an ecologically designed farm. I figured that the species that thrived on this site for the last zillion years, through ice ages and global warmings, had a pretty good chance of thriving here again! Instead of fighting the weeds in my carrot patch (I didn’t really mean to get on a kick with the carrots… Sorry, carrots!) I would FARM the weeds… The raspberries, and hazelnuts and plums and grapes and apples, the fungi and the chestnuts. WAIT? Chestnuts??? Yes… Chestnuts and Oaks are both members of the Fagacae family. They are cousins and have very similar site requirements.

After arranging the rows for perennials and the crop fields in such a way as to conserve and manage rainfall, I planted the species listed above. (there are a LOT more perennial edibles at New Forest Farm than just that short list. I’m just trying to keep things simple here) Through the years, abandoned farm fields of hard packed clay and corn stubble, and badly overgrazed, compacted pasture became an “early successional shrubland”, in species composition and in FACT. Thickets of shrubs and thorns didn’t invade my farm. My farm IS the invading thicket of shrubs and thorns, and sun-loving trees, etc. As this system has persisted through the years, I have done my best to manage it according to the “disturbance regime” that it would have encountered naturally, with fire, grazing and browsing. Cattle, pigs and fowl (chickens and guineas) have been the most common livestock. Although I’ve used fire, both intentionally and unintentionally, I mostly mimic the removal of grassy vegetation with an orchard mower, and the effects of the mastodon are imitated with a chainsaw, and the front-end loader of the tractor.

What has happened here through the years, is that the site has changed. First of all, the site when I arrived in 1995 had changed from the “original”. It was no longer “natural”. A corn field is NOT an Oak Savanna. My attempts at re-creating an agricultural Oak Savanna were taking place on a DIFFERENT PLANET! The atmosphere has more carbon in it than a thousand years ago, the rainfall has a different chemistry than 150 years ago. The soil was contaminated with the residues from 60 years of chemical application and plastic bags from Wal-Mart frequently fly overhead and land on the farm to plug the digestive tracts of cattle who ingest them and die (this has indeed happened here!)

Cattle and a mower are not bison, elk and fire. The species and the system still respond well however, despite the technical differences. Tiny hazelnut shrubs struggled for years within the grassy matrix, chestnuts, apples and grapes all begin to bear. As the shrubland has matured, it has changed the site. The dense, hard-packed clay has become a nice, fertile topsoil. (still clay derived and sticky when wet) The blazing hot open fields have become lightly shaded. The once aggressive grass has become somewhat tenuous, and in places sparse. Perfect conditions for garlic mustard, an INVASIVE SPECIES! Or wait… Is Garlic Mustard the invasive species or was I, moving in with my “foreign genetics”? (I grow American, Chinese, European and highly hybridized Chestnuts, American, Beaked, European and hybridized hazelnuts, Korean Stone pine, European Varieties of apples and pears, oriental medicinal plants and mushrooms, etc.)

Oriental bittersweet

Or was the “invasive species” the Norwegian dairy farmer who cut the trees, plowed the sod and grew corn (a non-native invasive itself, from central America) with chemicals? Maybe the invasive species were the unnecessary, non-native earthworms that came from Europe, and revered by “regenerative farmers” worldwide as some sort of sacred cow, which increased the available soil fertility out of the range for which most natives were adapted, and converted the deep, soft forest duff to a couple of leaves scattered atop layers of castings? Maybe the invasive species are the colony-nesting honeybees brought by the Europeans, which never existed in the Western Hemisphere and are not needed for the pollination of “native” plants? Maybe the invasives are the ring-necked pheasants or the brown trout, both non-native invasives that many folks like? Maybe the “invasive species” were the Native Americans who moved out of their “natural, native” ancestral homeland in Asia and Siberia who within a thousand years in North America caused the extinction of the nine species of ground sloth, two species of giraffe, the mastodons and mammoths that were here when they arrived? Maybe the “invasive species” were the plants and animals that “invaded” after the last “Big Ice” melted? Or maybe the invasive species were the mice that ate the eggs of the dinosaur that tempted Eve? The drama of succession and change has been going on for a LONG time. What IS an “invasive species” anyways? What is a “native species?” I’ll leave these discussions to others… I’ve got Garlic Mustard to deal with!

With even a beginners understanding of ecological succession and disturbance, we can more effectively play the cards that we’ve been dealt. We can ask ourselves some simple questions that can hopefully help us to figure out how to survive within the actual reality that we are in.

What are the conditions that this so-called “invasive species” enjoys? What soil mineral profile promotes their growth? Supresses it? What successional stage provides its preferred set of conditions? How can we prevent the appearance of those conditions? Can we adjust the current conditions so that the “invasive” is inhibited? What successional phase comes AFTER the phase that the invasive enjoys? What disturbances cause the “invasive” to thrive? What disturbances will “set back” the invasive? These questions and more, are the ones I ask myself BEFORE I interact with an “invasive”. Does this invasive species bother me, the production of my operation, or values that I hold dear? This last question opens up a whole can of very revealing non-native worms!

As far as we can tell, “invasive species” don’t really care what we call them. They just ARE. They live out their natural life cycle and exist under the conditions that support their growth, reproduction and spread. From their perspective, they have done nothing wrong. They are just living their lives according to their design. By living out their lives, they will change the conditions around them. They will persist as long as the conditions exist within which they thrive. This has nothing to do with whether you think they belong there or not. It has nothing to do with your mental construct called “invasion”. It matters not to the Garlic Mustard community on my farm if I think they’re “horrible”. They probably don’t even care that they might be causing the extinction of other plants. They are just being themselves. The “invasion” then, is in our mind. We have created the labels through which we now view reality. We have eaten from the forbidden tree and we view the world as “This is “good”, let’s plant more of it. This is “bad”, its invading! Lets eradicate it!” Yes, these things have been “introduced” from one place to another. Yes they sometimes have devastating effects on the local flora and fauna during the time that it takes for natural processes to kick in. How we view them and how we interact with them is up to us.

If we CHOOSE to, we can interact with them in such a manner as to limit their effects on us and local ecologies. In my opinion, using herbicide in an ecosystem is not good for ecosystem health. Perhaps “invasive” Japanese Knotweed is “not good” either. What is better? A rampant, pure-stand forming plant that really does eradicate all kinds of species in its wake, (for a period of time (unknown to us) until it changes its site conditions to those it can no longer tolerate) or the pollution from the factories that made the herbicide, contaminated groundwater from oil extraction, the wars and economic turmoil caused by petrochemical geopolitics, the cancer, the lawsuits, an altered atmosphere and endless suffering?

What your course of action is is up to YOU! If you want an “invasion” to stop, it is best to create conditions ahead of time that are not conducive to the species in question. If you don’t want Chestnut blight on your property don’t plant chestnuts. If you don’t want plum curculio don’t plant apples or stone fruit. If you don’t want black locust (or autumn olive) create shade as quickly as possible. If you don’t want a virus that spreads by close, unsanitary personal contact, then don’t cram ten million people into the same space and cut off the water supply to the sinks and toilets of those who failed to pay their water bill as is the case recently in Americas large cities. A species will only thrive when the conditions suit its growth, reproduction and spread.

If an unwanted species has already arrived at your site or is about to, DON’T WAIT to take action! It is far easier to pull the first one or two honeysuckle or buckthorn plants when you first see them than it is to eradicate ten acres of brush and have to deal with their seed sprouting for generations.

Autumn Olive

Autumn Olive

Be adaptable! When you see the first Bradford pears arriving in your field edges (or raspberries or blackberries) graft them to a preferred variety of pear and start selling grafted pear seedlings, fruit and juice. I was once hired by a winery to help them solve their issue with invasive blackberries in their vineyards. I suggested that they introduce a line of blackberry wine. They refused to “go with the flow” and within a few years dropped their organic certification in order to be able to spray the blackberries into oblivion. (My bet is that they are still fighting that war)

When you go with the new flow, be aware that new pests and diseases will invade soon thereafter! The epic drama, the game of succession is never ending. The conditions change and we’ll have to figure out how to play along. Attempting to destroy the stage to prevent a part of the show from happening is a downward spiral.

In the meantime, remember this while on your knees pulling weeds in your carrot patch. Pulling weeds to help your carrots to grow DOES INDEED help your carrots to grow! It is a choice that you are making. While pulling weeds you are on the front lines of humankind’s long history of attempting to stop succession. You will NEVER get all of the weeds out of your garden whether you’re using chemical weed control or are using certified organic methods. As soon as you cease your efforts, the invasion has won and succession runs its course. Your garden will continue to dance through time with the actors and actresses changing by the season and throughout the years, through wind and rain, and fire and ice, drought and flood. In time even all of our buildings will come down and become the substrate for the next phase of succession.

I hope there will still be some carrots growing somewhere…

Continuing Stewardship:

Giant hogweed dwarfing a propane tank, truly a case of: “Why did we let this happen?”

Stewardship = Presence… so I claimed four years ago in an article for the Ecological Landscape Alliance. With the passing of another 49 moons, with landscapes under ever more climate stress, and with continuing upward trends in pesticide usage, I wish to revisit that simple notion of Stewardship. I work in the world of invasive species, terrestrial plants more specifically, but everywhere I go, both in-country and abroad, I have asked others to clarify their understanding of land stewardship. While plenty of folks have touched on the idea of resource management, caretaking, and connection to nature, I was most deeply struck by two responses: “relationships” and “continuity.” Brilliant.

You may wonder why you’re finding an article on Stewardship in The Natural Farmer. Fair enough, but ask yourself a second question. Wouldn’t it be something if the spirit and principles of organic farming were applied to land management in general? To landscapes and resources everywhere? There are good teachings in the organic movement, as in the world of permaculture, but I submit that the spirit of good stewardship is important not just for our farms and pastures, but also for our woodlands, rivers, schools, our business organizations, and even our lovely backyards. Stewardship IS about relationships: to nature, to self, and to one another in diverse communities. Stewardship is also continuity, positive actions carrying through time and across generations.

I believe farmers and growers grasp these ideas; moreover, they appreciate the dynamic nature of their trade. Anyone who works the land and builds soil knows that the agricultural landscape is a nuanced place, always in a transition of some kind. Should you happen to be absent during these endless cycles of transition, you’ll be sure to miss something. Something vital, a signal that perhaps could have served you well. Remember: if a tree falls in the forest, and there is no one to hear, does it make a sound? I would push the question a little further. If that tree falls in the forest, but no one is listening… what then? Does the sound or anything else that might happen even matter? Presence: it’s all about being there with the senses in full-open position.

A long-term approach to landscape transition forces us to hone our craft, pick up cues and recognize forces at play. We learn that different times of day offer different perspectives; we see by evening light all the patterns and signs we missed in the morning. We learn that wild parsnip may grow seven feet tall, but under stress it comes down to hide just below the goldenrod. Clever indeed; parsnip can also flower at only three inches tall, right into October. No mystery any longer in understanding why mowing regimes simply never keep up. The lessons we learn in our own spaces translate well up and down the road; in engaging our neighbors we compare notes and concerns and perhaps pool resources.

Personally, my choice to be present with people or things or places is an indicator of respect, care, and connection. Professionally, and particularly in regard to vegetation management, my presence represents commitment and a determination to be there when things happen and to be proactive before even more things happen. Most calls I receive involve situations that are way out of hand. In the world of fruit tree pruning, it can be impressive to stand among trees that have not been managed since forever. Wow, but with invasive vines or the family of “danger plants,” years of inattention can be a disaster.

Now here are the South Burlington Vermont Youth Conservation Corps members feeling good about their work removing common buckthorn, glossy buckthorn, multi-flora rose, honeysuckle, and autumn olive at Wheeler Nature Park.

Presence allows landowners to avoid crisis, to see situations early, and to act appropriately. Actions can be clearly focused and incremental, rather than cases of periodic and overwhelming crisis management. The financial angle is also simple: minor annual commitment equates to avoidance of massive outlays every five or ten years. View it as an annual health check-up, although land should be visited much more frequently.

I try to monitor my project sites at least twice a year; this is how I uncovered the magic formula for shrub control. I found that shrub species cannot handle three stress events over two growing seasons. What does that mean? If I absolutely deny photosynthesis by girdling or stump-cutting an autumn olive tree, it will draw from its root reserves and re-sprout. But if I come back and strip that re-growth, it will have to return to the storage vault once more. A second visit to strip sprouts will likely be the end of that individual. Three stress events that allow insufficient time for recovery; this kills off most of the target shrubs while also breaking seed production. I go into the third growing season having few survivors to track down and two years with no seed rain saturating the soil. If I have begun addressing the immature shrubs while fostering recovery of the natives on hand, I am well on the way to successful site transition.

We desperately need more presence on the land as we find ourselves ever more disconnected from the natural world; climate change has only accelerated fear factors and added to the urgency of that need. Yet in the realm of vegetation management, we continue at all levels to defy nature’s steady push for balance and resilience. We curiously fail to approach the challenge of high-impact invasive species with a cooperative unity, turning to aggressive chemicals as a matter of routine. Such is our mindset in 2020; I prove the point with an informal survey from the 2019 national invasive species conference.

Successful management? I would like to think so. See all the cut stumps? A second VYCC crew enjoys the majesty of the oak tree. No soil disturbance here, and the spiritual pull or magnetic charm of the oak tree now attracts people at all times of year. I find fairy houses and message stones all over this site. No chemicals… simply no need for them. And now an added value, a meaningful attraction on a once insignificant and overrun forest path.

Prior to my presentation I asked the audience whether any among them were from the world of recreation. Then whether any represented the tribal nations, whether anyone made a living from agriculture, and whether any were attending on their own dime. Never did more than two hands go up among an audience of perhaps eighty people. It is a true failing that so few interests were represented at a national meeting; we clearly have work to do. Beekeepers, golf course managers, mountain bikers, beer makers… where were all those who benefit daily from functional landscapes and clean water? Managing landscapes for healthy ecosystem function is similar to the world of safety; it requires all of us to participate with commitment and awareness. Constantly, all the time. Showing up once a year simply doesn’t get it done; all of us need to show up and create real synergy. Government’s role would be to remove the financial obstacles preventing us all from working together.

A second example highlights our twisting or even full abandonment of the now hollow notion of Integrated Pest Management. In October of 2018, Cornell University researchers published an article detailing alternatives to glyphosate for weed control. The article gave short shrift to the techniques of flaming, mentioned only two hand tools, the shovel and the weed wrench, and made no mention whatsoever of solarizing or grazing. This article appears online with the university’s seal of approval; it clearly comes with cred. Yet, incredibly, there is no mention of the potato fork, the #1 tool many of us use to gently ease taproot species from the soil. I love the potato fork; I have one for each hand and refer to them by name. With practice one can remove many wild chervil plants while barely disturbing the soil structure. I here submit that no one should write articles on invasive species management if they have never met a potato fork. Nor, even more disturbingly, should they then pretend to possess enough methodology background to lay out a cost comparison. Where’s the data on that? How do you value the full suite of outcomes fostered via the long-term stewardship approach versus the singular focus of short-timeline chemical management? Forget apples to oranges, this is apples to planets. Yet this is what the public sees, this is what we spoon-feed landowners through the extension service and state agencies. Glyphosate is the tool you need folks, cheapest and most effective; that is the message, completely endorsed by our university system.

It gets worse, actually. I have had educators from another university inform me that my project sites are too successful. The work is so thorough (on a half-dozen target species) that there’s not enough to show people from a demonstration standpoint. Odd, considering that I benchmark my sites with before and after photos. In fact, here’s a good ‘before’ photo of mature buckthorn and honeysuckle in a fairly stable woodland.

These young people are the future landowners, community members, environmental leaders, and scientists that we need. In our present mindset of crisis management with chemical methods, we are not growing resource stewards; in fact the dis-connect from nature grows wider every year. How do we reconnect people to cherished landscapes? How do we nourish the soul and even perhaps rehabilitate those who’ve lost their way? Time on the land would grow new stewards, with the generations sharing knowledge and diverse faces offering fresh perspectives. Why are resource stewards critical? Because there is no such thing as a landscape or project site completely insulated from “the outside world.” We need people tuned in to the nuances of the natural landscape, people who know the disruptive exotic species to watch for. Chemical approaches do not build that pool of future resource stewards; project “deliverables” include only immediate results, the percentage of mature plant kills. Do the agencies realize that all their grant-funded eradication work is doing absolutely nothing about the seeds in the soil? Everything will return in a few years if the land managers themselves do not return.

How can it be that we place such little emphasis on empowering our rising generations and our struggling communities? Why do we TALK about Integrated Pest Management, but choose to fund only chemical approaches? I have seen this, just last year with a fair amount of coin involved. $50,000 was available to execute a chemical treatment program, but alternative approaches were ineligible for funding. No goat grazing, no training of locals and neighbors, no long-term manual control drawing from the local labor force. There was no willingness on the part of the managerial non-profit to pay volunteers or professionals outside the realm of the herbicide practitioners. Completely disingenuous in my mind… a lost opportunity and a waste of good money. Even with only a few neighbors actively participating, a people-power approach with non-chemical methods would have cost far less than fifty grand. And the takeaway (deliverables) would have included a group of people trained to work safely and capable of preventing the next crisis. Sad to see that antiquated mindset holding people back; time for some evolution.

The above story is no isolated incident from 2019. I encounter similar scenarios routinely, big money steered toward the herbicide approach. Little has seemingly changed since my first invasive species conference in 2005. Even back then I noticed attendees obtaining pesticide certification credits for their conference participation. No other credits were offered, however. The herbicide professionals were organized and licensed, which is a good thing, but no other management approaches held such acceptance and high standing. Throughout the day I heard how difficult exotic species can be with devastating economic and ecological impacts. Keywords like Early Detection and Adaptive Management abounded, but there was no mention of Presence, no acknowledgement of stewardship continuity and community relationships leading the way in landscape rehabilitation. All energies seemed to focus on winning the battles with singular high-impact species, the War on Weeds mentality, rather than rebuilding soils and reflecting on our management shortfalls. I recall no exploration of economic positives associated with non-native species (with the exception of garlic mustard pesto, apparently a favorite dish of land managers). I enjoy the pesto as well, and plan to roll out Japanese knotweed crisp later this summer!

So here I wish to thank you all, you reading this fine publication right now. Thank you as I enter my tenth growing season as founder / owner of Got Weeds? You provided me early on with both the challenge and the opportunity. In the company of farmers and growers is where I first heard that the farmer’s footsteps are the best fertilizer. Not long after, I decided those same footsteps might also serve as the best herbicide. At a Soils gathering I heard John Kempf firmly (but kindly) remind an audience member that one is not truly on the land if one never gets off the tractor. Thus we come to understand Presence.

I have thanked you, and now I call upon you. To act and to instruct and to share your appreciation of Presence. You know the value of brush piles and the power of forward-thinking. You understand the dynamic nature of landscapes and the plant populations they support. But Presence is a word as alien to agencies and academia as the undesired species themselves. There is simply too much land and too many exotic species for us to be present everywhere all at once, no?. False, absolutely wrong. The issue is that we scatter our efforts and seek to impose our human calendar on that of the plant world. They go dormant in the fall, and we shut down as well. Farmers and growers know better, that autumn is the time to set the stage for next spring’s growth. Feed the soil and stress the invasives right until the ground freezes. Find that focus, hone that edge.

Readers of The Natural Farmer also appreciate nutritious food and all the work behind fine culinary creations. You will appreciate my point when I urge a halt to the relentless harvesting of ostrich ferns for the hipster dish known as fiddleheads. We lament the loss of our riverbanks to Japanese knotweed monocultures even as we hammer their chief competitor year after year. Were we even slightly more informed, we would know that small, tender knotweed shoots can also be sauteed and served up with garlic butter. Imagine the ecological impact over just a single year if we suddenly shifted to a diet of knotweed shoots instead of fiddleheads. But wait, will anyone be interested in fresh greens coming from land with a chemical legacy? Or knotweed crisp or garlic mustard pesto recently slathered with pesticide sauce? Hmmmm.

I shall return to the issue of toxins and cumulative effects and climate impacts. For the moment, let me offer some details on managing invasive or “undesirable” plant species. Most invasive species are good colonizers, even the natives like poison ivy, so they are well suited to poor soils and disturbance. They are often beneficial in some way, taprooting to bring nutrients up from the depths or covering bare ground quickly to suppress erosion. That said, there are occasions where we wish to prevent an incursion of exotic species, perhaps in the name of public safety as with wild parsnip. My message of Presence simply recognizes the value of early detection and an informed read of the landscape. To successfully transition the space, we need to cooperate across boundaries and work strategically, choosing our locations and timing our actions. What is the vision, what are the plants on hand, and what will the landscape allow?

1. First, some species truly are tenacious, and the value of prevention in that realm is immeasurable. While single plants can be successfully removed, issues begin once they have gained a foothold and begun dropping seed or growing the underground network. Do not allow such plants to establish at all; this includes goutweed, comfrey, Japanese knotweed, bedstraw, bindweed and wild chervil. Goutweed happily hitches a ride in the soil of potted plants, so biosecurity is an important prevention keyword. And this is not about whether the plants have economic value; yes comfrey and plantain and knotweed and burdock have serious beneficial uses, but it is completely irresponsible to introduce those species into new spaces. So I submit. We can argue about it, but planting hardy kiwi vines down the road from a centuries-old apple orchard is not particularly neighborly, and yes, I’m aware that the apple varieties are likely non-native imports as well.

2. Success is all about transitioning landscapes. We accomplish little by eradicating a target species while allowing four others to take advantage. People ask: “Mike, have you ever successfully eradicated Japanese knotweed?” I reply that I have created enduring forest plots where Japanese knotweed once dominated. There are now fifteen foot tall trees of several species where once only knotweed stood. This would not have happened without intervention, and those trees will now last what, 200 to 300 years? Even if the knotweed does return, the landscape has shifted. Conditions are not quite so favorable, although one single weather event could certainly alter things. For the record, through Year Nine on my oldest knotweed site, I found a total of 35 tiny knotweed stems, all of which were extracted before reaching one foot in height. Most were around three inches; I have to keep track of their locations with flagging. More brief site visits in Year Ten will prevent any recovery.

Common buckthorn stumps are silhouetted against a precious and functional wetland.

3. It is much easier / simpler to manage hotspots than endless infestations. Learn what a Weed Drying Station is and build one of your own. Total cost: zero dollars, one half teaspoon of sweat. While you’re at it, designate a few places for brush piles to decompose. This is your future soil… within a few years you’ll have beautiful material to fill divots and woodchuck holes. You truly don’t need to torch that vegetation and watch the pile become yet more CO2 in the atmosphere. Vegetation is a resource…. know that above all else. Brush piles also support ground-nesting birds, so build your credibility as a conservationist. The photo illustrates how I protect an open space sloping into a fairly pristine wetland.

The stumps are common buckthorn encroaching outward from the woodline. The flagged apple tree, the cedar, the sumac stands, and sporadic grey dogwood are allowed to thrive in the name of species and habitat diversity. No need for toxins and no need to burn off the brush. Even if there are viable seeds in the piles, I can smother or pull those easily later.

4. Know the land and what happens upon it. Then be sure you know where the sun is. Know the flow of water as well and where the prevailing winds originate, but sunlight is the driver of plant life. And something quite crucial happens around the 4th of July for many invasive shrub species. Your local calendar is the one to follow, but in Vermont early July is when fruits begin to harden off their seeds. Until then, any heavy stress event on an invasive shrub pretty much breaks seed production for that growing season. This is why I target the larger, fruiting shrubs earlier in the year. I still pull, cut, flame and girdle all the way into December, and while that work is important over the long term, it does not break the seed cycle. With a four to five year seed life, many shrub species can rebound from an initial, aggressive control effort. I contend that Year Three is often the most difficult year for transitioning sites. Mature shrubs may still be hanging on, new plants are bursting from the soil seed bank, and the installed or favored native species are not yet competitive. Few things are more rewarding than reaching Year Four and seeing the shift gain traction. The beech, dogwood, maples and white pine are accelerating, while the stressed buckthorn and burning bush are fading under the constant pressure.

5. Just this month I discussed with clients how they might execute a harvest or thinning of their woodlands. Imagine an expanse of relatively healthy forest with a weak but opportunistic presence of invasive species lurking within and nearby. Perhaps it’s barberry and bittersweet along property lines or patches of honeysuckle and garlic mustard at trailheads. Yes, absolutely get in ahead of the heavy equipment and begin suppressing exotic species. But equally important is figuring out where and how to begin. I ask: if the sun is toward the south, would we not want to keep some kind of barrier in place as we open up the landscape? Even if the barrier is a wall of buckthorn trees, would that not have some limiting effect? Can we use the invasive species on the southern boundary, even just temporarily, to prevent sunlight from reaching their own offspring? Ironic, no, but is that not wiser than starting to clear on the south side? If possible, if conditions allow, this is the kind of creative strategizing I encourage.

Noxious wild parsnip plants flower among Christmas trees. How does one work safely here?

Let us move now to the subject of chemical treatment programs and herbicide usage. My goal from the beginning has been to reduce our overall pesticide usage. I maintain we could have achieved reductions over the past twenty years had we simply chosen to use our brains and problem-solving abilities. Sadly, little has changed in that realm since Got Weeds? has been in operation; I still see county foresters promoting chemical methods as the go-to option and consumers thoughtlessly self-interpreting the meaning of “in or near water.”

I see no attention whatsoever to cumulative effects, no understanding that our lands already carry a toxic legacy even while enduring more frequent and severe disturbance events (hurricanes, floods, etc.). I see farms and communities struggle with invasive species; they did not directly cause the problem but are left with poor quality hay and public safety hazards. There is no funding to help people learn about real-world biosecurity and equipment cleanliness. What’s the fix?

Well, one idea might be to stop furthering the harm with yet more toxin. Allow the soil to heal, train people to listen to their landscapes and discover something about themselves as well. Chemical approaches have always been short-term in nature, failing to address the seed bank on site and simply not welcoming participation by community members. I realize that scouting organizations conducted outings with backpack sprayers in the past and cities even organized Spontaneous Weed Action Teams (SWAT), but the safety issues can no longer be so easily brushed aside. Manual and mechanical treatment methods offer the best opportunities to train field stewards of the future. We need those eyes and feet on the land.

Look to Pomfret, Vermont. Some twenty landowners support the goal of preventing wild parsnip from taking hold in their neighborhood. The result is a landscape free of wild parsnip infestations, even as adjacent lands are completely overrun: collective stewardship. The roadsides are not “clean,” but the annual colonizers are intercepted annually with vigilance and potato forks over several square miles.

From a different angle, the wild parsnip has been pulled prior to viable seed formation and piled for drying. See the potato fork?

My final arguments against herbicide usage center on the CO2 impact and the idea of supporting businesses in line with consumer values. To passionately support organic farming and buy local is no longer sufficient; we as communities need to press our utilities and our non-profits and state agencies to STOP with the mindless application of toxins year after year. We can take what we’ve learned on the farm and grow a larger positive, a broader benefit for human health and watersheds everywhere. The power of the consumer is simple, and we should ask: “Would we rather support a local small business with five employees, or instead send our money to some multinational corporation manufacturing toxins in a faraway city?” The utilities should pay landowners to graze animals under powerlines, and states could pay people NOT to burn brush piles. Wouldn’t that be an ecosystem service, the act of NOT burning future soil? We talk of payment for ecosystem services…. Pay up, I say.

Regarding the carbon footprint, I see four CO2 impacts directly associated with pesticide usage, but this always seems to escape conversations on sustainability and climate change. Institutions of higher learning make abstract claims to lead the world in sustainability and green operations. Do they account for their annual use of pesticides on managed lands or for insect control? Pesticides require energy to produce, more energy to transport, yet more energy to apply them on site, and then in the end they break down into compounds such as formaldehyde and CO2. A fourfold CO2 impact, according to my math. And what about the utilities; is their vegetation management program included or held up for CO2 scrutiny? We should all be asking this question. I found nothing in the 2020 Vermont legislature’s Global Warming Solutions Act (H. 688) to address pesticide usage. Nothing… it’s almost as if pesticides get a free pass. Why is that?

So if you truly wish to keep your meadow free of invasive species, try this: return the herbicides for a refund and think about how you might build protective belts around the space. A meadow with bedstraw and bindweed is already suffering, but it can get worse if wild chervil and burdock and others decide to join in. This protective belt approach broadly applies to any economically valued space: hayfields, recreation areas, an orchard. Rather than hiring someone to walk transects back and forth all day, get real about biosecurity at the entrance gates and take steps to clean any equipment that comes and goes. Then, study the perimeter. If you were to allow “the Big Leafies” to establish on the perimeter, then commit to a mowing / scything / grazing regime in a strip along that edge, you would have two belts for control. First is the dense vegetation under which nothing can get started (perhaps encourage pokeweed, elderberries, and bee balm). Second is the tightly mowed grass strip serving as a no-grow zone. Any weeds desiring that central protected space must first penetrate the outer belt with their seed heads and then propel seeds across the mowed strip. Not impossible, but any of us could walk that groomed path and pick out undesirables in the protected interior. Potato fork in one hand, beverage in the other. I promise this is not hard and chopped hay along the edges doesn’t really dry well anyway, so productivity loss is micro. The most important consideration is to keep the mower blowing from the “clean” space into the “contaminated” outer space. And what about round bales, those big 800 pound marshmallows dotting the hayfields? Why not park them as a protective belt around the hayfield’s most exposed edge? Nothing grows through round bales, so they could double as elements of the biosecurity plan.

A hayfield is protected from the upslope roadway by a wall of burdock and a tightly mowed perimeter strip.

At the bottom of this page is a hayfield protected from the upslope roadway by a wall of burdock and a tightly mowed perimeter strip.

The photo illustrates the protective belts model. The hayfield has value, but the introduction of wild parsnip and wild chervil seed along the roadway is a constant. No worries, allow the burdock to form a wall and maintain the mowing strip. Burdock is not the ideal, not even native and those seed pods are annoying, but anything is better than dangerous parsnip. Morning walkabouts are good exercise and allow the owner to easily proof the field edges. Monitoring made easier. She should probably change direction with her mower though. Mow clean sides first?

Earlier I mentioned the potato fork and its most-favored status among all the tools I carry. Allow me to explain. The best thing about Presence is enjoying the place as if I’m not even there, just feeling it carry on as it otherwise would. I don’t want the tree to have second thoughts about falling just on account of my presence. So I move quietly, thoughtfully, and when people hire me to transition their landscape vegetation, it is much the same. Come in, acquaint, connect, safe the site, perform the task, set the stage for follow-up, and step away. Make it seem as though I was never even there. Solarizing can look a little aggressive with the sheets of plastic, and brush-hogging is equally jarring sometimes. But the potato fork is the ultimate tool for herbaceous weeds. A little pry on two or three sides of the target plant, then a steady lift. Gentle upward pressure with gloved hand on the stem…. steady… keep going… and there you go. Out it slides. Lightly shake off soil, inspect the root for break-offs, then onto the drying station. Tamp down the cracks in the soil and clean tools before leaving.

I can pull thousands of weeds a day, and other than a certain color or texture now missing from the landscape fabric, it’s almost as if I had not even been there. Just how I like to leave it. The only legacy is cooperative relationships and enduring continuity. That’s how this weed guy manages to be everywhere, all at once and at just the right moment.

Oh look, is that a new moon?

Michael Bald founded his company, Got Weeds?, in early 2011 to offer non-chemical weed management options to landowners in central Vermont and New Hampshire. His focus is on long-term site stewardship, soil health, and native plant diversity; Mike seeks to integrate the worlds of invasive species, youth education, organic farming, and sustainable operations. With a BS in Biology from the University of Notre Dame, four years of service in the Army Corps of Engineers, and nine years working for the US Forest Service in Vermont, Mike appreciates the importance of healthy habitats, site specificity and ecosystem resilience. Got Weeds? has offered manual and mechanical weed control alternatives for ten growing seasons; Mike’s specialty areas include solarizing, management of “the danger plants,” and training workshops for groups and landowners.

Thoughts on the Pandemic

I suspect I share the reactions of many TNF readers to this pandemic. Fortunately, Julie and I do not know anyone who has been seriously infected with the coronavirus, and our livelihoods are not impacted by the economic shutdown that so many have experienced. Farming has been declared essential and our work for NOFA was always done at home.

But this crisis has shown all of us that Nature has the final say. She has been a tolerant mother, generously giving us whatever of her treasures we asked for – despoiling her air, privatizing her water, mining her soil. But, never sated, we always pressed for more.

Now it seems that we may have transgressed too far, crowding our fellow living creatures into cages, pens and CAFOs for our consumption, raising them without sunlight or space or fresh air. In their misery they have succumbed to disease, allowing new contagions to thrive, evolve and finally escape out into our world.

Is social distancing working? Can the curve be flattened? Will the world we knew return? I don’t think we can yet say. This is all too new, too much information is unavailable. But there are a few things which I think we have learned:

First, no one can deny the simple power of Nature. When she is displeased, all the might and money of the human world count for little.

Second, this crisis did not come from outer space. It has been predicted for years, years during which the warnings went unheeded, preparations neglected. We have been poorly served by our leadership, all of it.

Third, we have all been born with a precious gift — an immune system — which is designed to save us from exactly this threat. But that immune system needs to be supported with proper nutrients and not assaulted by toxic chemicals. It arises from the gut biome, which can be fatally damaged by poisons like glyphosate (see issue 123). Among other things it requires lots of sunlight to make cholesterol into vitamin D (see issue 126) — whose lack has been so obvious and flagrant in the terrible infection rates of northern hemisphere countries versus southern hemisphere ones this spring. Is the reason no one in power is raising these questions because there is no profit in good health?

Fourth, awakened individuals are responding to this pandemic with resolve to do better. The tidal wave of consumer interest in gardening, local food, CSAs, farmers markets and farm stands has surprised all of us. It gives us an opportunity we haven’t had since the 1989 Alar scare to challenge the global food system: to show how chasing convenience and price has been at the cost of food quality and our health, how we need to take personal responsibility for what we put in our mouths.

Fifth, I find it personally ironic that the life so many of us have chosen, to eschew the fast lane and its built-up world, to grow food, raise healthy families and work with Nature has been so thoroughly validated. Security and success have taken on new meanings.

No one can predict how this will all turn out. As a species we have a consistent history of returning to the tried and the comfortable as soon as possible. But we also have moments of keen insight and fundamental change.

The international food system, with its chemicals and its CAFOs and its corporations, could find ways to patch this together another few years. But life is nothing if not persistent, and infectious organisms seem very much alive. We have uncorked a genie here which will not withdraw for long.

We can choose a path which leads to further distancing from life and its senses — communicating electronically, working in isolation, estranged from our food, sanitising our social events.

Or the wiser minds among us might realize we must adapt to Nature. We must learn good manners, which means the same in matters large or small — restraint for the self, respect and generosity for the other.

Can we embrace the flesh and blood we are, live to excel at good health, start to undo the damage we have done?

It is for us to choose the path we wish to follow.

Letters to the editor on Invasive Species

Dear Jack,

Sorry I haven’t been able to respond earlier – your Summer TNF arrived just as the busy season began and I haven’t got much chance to sit at my desk with a pen since then.

Thanks for pointing out the lack of clarity in my letter to the editor last issue. All of my criticism of cannabis has to do with THC and the culture that has grown up around it. I have no objections to CBD or any other hemp products – in fact I know almost nothing about them. And almost everything I do know about them I’ve learned in the last two years of Vermont Canna-mania. Before that I only knew that my very old bee books and yearbooks of agriculture were printed on hemp paper, and that’s why the pages are still white and unfaded after all these years.

I’m glad that CBD is helping you and many others with arthritis. I may need it someday myself, but so far sunshine and bee venom seem to be keeping my joints working fairly well.

All the best to you and your family and keep up the great work.

Best Wishes, Kirk Webster


This tribute from me to you is long overdue. I don’t know if you or someone else came up with the idea of theme issues for The Natural Farmer but it was brilliantly conceived and you have brilliantly executed it. As time has gone by, you have gotten better and better at finding experts with thoughtful opinions and absorbing stories to tell.

You have produced how many (160, maybe?!) of these issues in 40 years, so it feels a little silly for me to say that this last one on invasive species was maybe your best yet. Beyond the sheer volume of information, I was so impressed by the wide range of perspectives and opinions expressed.

Of course, the highlight for me was Bryan O’Hara’s passionate yet tongue-in-cheek turnip fable. Bless you, Bryan! But the other highlight, Jack, was your eloquent essay on the pandemic. You nailed it.

Jack, you and I haven’t always agreed. (Why should we? If everyone is thinking the same no one is doing any real thinking.) But in your illustrious editorial career you have exemplified the power of open-minded journalism. At a time when our wannabe fascist president threatens the very core values of our republic, you fight back with your free press, one of the very cornerstones of those values! Thanks you!

PS I know that Julie also deserves a great deal of the credit. Thank you, Julie!

C. R. Lawn, Colrain, MA

Dear C. R.,

Thanks for the fulsome praise! Actually the themed issue idea was a trick to get folks to write for me. They could always put me off when I asked, but when it was for an issue on the theme that turned them on, they didn’t want to miss it!

We are not done with Bryan O’Hara and his turnips yet! Wait until you see the rest of this letter section.

And thanks for the support on the pandemic essay. That was bubbling up in me since the beginning of this experience we are all going through. The issue of the paper in your hands right now is also a product of such thinking and questions. I hope you like it!

— Jack

Dear Jack,

Thank you for yet another great issue of TNF! I found the article by Jomo Neiger especially thought provoking, though I wonder if you did not mislabel the tree on p. 18. Looks suspiciously like a Black Walnut.

I would like to respond to your “Thoughts on the Pandemic.” You have written a beautiful essay connecting the pandemic crisis with the deeper crisis of human distancing from Nature. You point out with simple eloquence the hopeful responses that people are making in a “tidal wave” of gardening and buying local food. Along these lines, I heard from Shi Yan, the Chinese representative to Urgenci, the International CSA Network, that once again, as China has to reclose due to an upsurge of cases, the CSA farmers cannot keep up with soaring demand for their food. And you savor the irony of the confirmation of the choices that us natural farmers have made to stay off the fast track and learn to live closer to Nature.

In conclusion, you lay out the choices that human society will have to make as the Covid-19 threats subside. Will we go back to the old normal of corporate control, chemicals and CAFOs? You put it so well – “But life is nothing if not persistent, and infectious organisms seem very much alive. We have uncorked a genie here which will not withdraw for long.”

Your conclusion, however, seems to reduce the path ahead to a moral, individual choice. I grant you, that is a critical part of what faces each of us. But quiet moral choices will not be enough. If we want the new normal to be anything like our visions, NOFA will have to join in collective action with the other sustainable agriculture networks, farmworkers, the Food Chain Workers Alliance, the HEAL Food Alliance, faith groups, Sunrise and other uprising youth, Black Lives Matter, Fight for 15, the labor movement and too many others for me to try to list. We have to get out there in the dirty old policy arena, turning the transformed food and agriculture system we want for the future into legislation and programs that real world agencies implement. It is time to go beyond tinkering with the crumbs from the Farm Bill table. Farmers will be able to afford to farm more ecologically, if we push for structural changes in the entire food system that will revitalize farms and rural areas. We need to flesh out in detail programs based on our lived experience for the Green New Deal (GND) resolution that Senator Markey and Congresswoman Ocasio-Cortez put on the national table.

Here are my thoughts about what this might look like.

First of all, family-scale farms need a system of fair pricing, that is, parity with supply management with support for prices that cover the real costs of living and farming, including conservation practices that regenerate natural resources.

Parity pricing and supply management should also be extended to other crops.  Since fruit and vegetables are perishable, we need public investments in value-added enterprises that could be farmer or worker-owned coops in every county where these crops are grown.

Next, farmers need contract reform.  Farmers that sell to bigger entities need legislation to protect their rights to freedom of association so that they can form groups or cooperatives to strengthen their bargaining position in negotiating fair contracts without threat of retaliation.  In addition, a limit must be set on the middlemen’s share of the final shopper dollar: if prices go up, middlemen must pay farmers more; if the prices processors pay to farmers go down, the point of purchase price for shoppers should also go down.  With control by mega-corporations an ever greater threat to family-scale farming, the GND must be linked with anti-trust measures.

All farmers should be eligible for GND programs whether they own land, rent it with cash payments or through share cropping.

The GND should include measures that are essential to establishing farm work as a respected and fairly remunerated profession. Like farmers, farmworkers need freedom of association so that they can form groups or unions to negotiate fair pay and working conditions.

To invest effectively in “drawdown” of greenhouse gases (GHG), the GND must include incentives and training for farmers to become the true managers of solar power that photosynthesis makes possible using the basic systems of regenerative organic agriculture.

The GND should preserve farmland and discourage sprawl. Tax and other incentives can make preserved farmland available to new farmers.

The GND should also ban speculation on agricultural commodities and farmland since this drives up the price of land and food. Strict regulations should control investors who are not producers or final users.  Food derivatives markets should not be used as investment vehicles by banks and investment funds.

A “Just Transition” in agriculture means providing access to farmland to those from whom it has been unjustly taken, the reparations called for by farmers of color and Native Americans (

Farmworkers should have the opportunity to become farmers. It should also include retraining for the farmers who now farm thousands of acres to use regenerative practices with a buy-out scheme for CAFOs and provide incentives to farmers to reduce their production of bio-fuels that take land out of food production. Instead, farms could receive payment for other kinds of renewable energy production that makes use of marginal land, sun, wind and the heat of the earth.

For supply management to work, imports must be limited to crops that US farmers cannot produce on land in the US.

So, as you write, Jack, let’s “undo the damage!” Let’s be active players in an historic popular movement for an ecological society!

For Peace in Our Lifetimes,
Liz Henderson

Dear Liz,

Thanks for your program for changes needed in US ag policy. You may be right that some of these are needed, although as I get older I am not so sure that I know what is needed in all cases.

Along with many other small family farmers, for instance, I don’t think we on our farm are able to afford to pay wages starting at $15 an hour (as you suggest in calling for us to support the Fight for 15) and even in this seller’s market we are managing to break even only by taking advantage of WWOOFers and other volunteer sources of help. We are trying to sell healthy food to working people and they have budgets. We do take SNAP and offer work shares as ways of making the food more affordable, but we are conscious of charges that organic food is only for the elite.

The permanent workers we have trained over years make more than $15, but they have worked their way to that. If we had to start at $15 with everyone, experienced or not, willing to volunteer or not, we would have to fold. I’m not sure it is fair to those who have found long term jobs here, where we eat fresh farm food as a team for breakfast and lunch, enable working mothers to bring their kids for healthy care, and include staff in decision-making and planning, to say we have to shutter the business and hope they will be happy working at Walmart. There is considerably more to a job than the paycheck, and those who share my view and appreciate “quality” employment ought to be able to find it, even among employers unable to start them at $15 an hour.

My point in the “Thoughts” article was to reflect on the Pandemic itself and particularly on the complete lack of discussion in any public media I see of the responsibility of individuals for their own state of health. That survival during this period is based on one’s health care coverage or obedience to rules of masking and social distancing compared to what one has been putting into one’s mouth for the last 20 years is ludicrous.

Were I a proponent of the cancel culture I would urge that any such statements be censored as patently false and potentially fatal advice. As a libertarian, of course, I think ideas, even very controversial ones, should be propounded and discussed and that sunshine and a breeze are the best way to air things out. But that medical doctors and officials responsible for the good health of the nation, when discussing the Pandemic, should ignore the surfeit of “fake food” that our culture is awash in seems truly criminal. They must know better. The realization of the abysmal level of public debate on health in this nation spurred the publication of this current issue with its focus on Food as Medicine.

So thanks for your urgings and good luck to your causes. We have a process in America, flawed as it often is, for making sense of all this: discussion, debate, and thoughtful consideration of the views of others. I hope the Natural Farmer can play a very active role in this and I hope to be able to continue doing this for a while longer!

Dear Caro (Roszell) and Doug (Cook),

Hey, you two! I know you are not the editors of the Natural Farmer newsletter but I know you two and figured you could perhaps pass this on (through NOFA) to the correct folks and let them know that I’m not simply a crackpot with an ax to grind. I was excited by the recent supplement on invasive species (The Natural Farmer Summer 2020) as this is an issue that seems to still be pretty low on many people’s radars, especially within the farming and permaculture communities. Things started off well until I got to the article written by Bryan O’Hara. I understand that NOFA is trying to bring multiple viewpoints to its readers, it’s a strategy that I applaud when the issue is one of the differing viewpoints but in this case, NOFA has printed an article that makes claims that have been proven false numerous times.

NOFA is an organization that people look to for information leading to better land practices, yet the points in this article instead make light of major ecological threats and encourage people to grow species that are well known to destroy ecosystems. The article starts off by making the claim that “invasive” is all about a point of view, claiming that the idea of invasives is due to “the human separation from the lessons of nature”. It’s an argument that could work if applied to plants such as goldenrod or ragweed but falls apart quickly when one considers the fact that invasives are species that would never have arrived to North America without human transport (i. e. humans were directly involved and by no means separate).

The author then claims that the major losses of species are caused by diseases and not invasive species and yet the examples he offers (American Elm and American Chestnut) were both decimated by invasive species (in this case invasive disease species). He goes on to encourage people to plant invasive wineberries and makes the claim that garlic mustard invading a forest will benefit soils by increasing photosynthesis in the thinning understory. What he doesn’t seem to understand is that garlic mustard releases numerous allelopathic chemicals into the soil, namely allyl-isothiocyanate and benzyl-isothiocyanate, which kill off mycorrhizal fungi in the soil leading to the decline of trees in our forests, a fact that has been proven in published scientific literature. The garlic mustard is not helping to fill in a canopy that is thinning for some mysterious reason, it’s killing the trees directly and choking out any healthy understory that might be able to take the place of those trees.

As I think both of you know I am anything but a purist when it comes to invasive species, I recently wrote an article for ELA about rethinking black locust arguing against its label as an invasive species and I will happily argue against the overuse of glyphosate on the landscape, especially in a battle against an invasion that simply cannot be won. My arguments are not coming out of an outdated approach of labeling good plants and bad plants but from current ecological research. The article in the newsletter is not a different opinion but instead a statement of incorrect information. If NOFA is going to print something that folks will use to make changes on their landscapes it behooves the organization to fact check the opinions presented. This is disappointing from an organization that I have thought deserves my support and makes me rethink my role as a member of NOFA.

With respect for the work that I know you two are doing,
Dan Jaffe Wilder

Hi Dan,

Thank you for reaching out.  I hadn’t read Bryan’s article yet (honestly, I hadn’t even cracked open this issue at all) so I went ahead and read it.  I think you’ve made some particularly important distinctions about our role in “invasive species” not being as simple as a lack of a certain perspective.  As well, the large photo of Garlic Mustard with the complimentary caption will likely incite some very strong reactions.  While I am low on the pole as far as the Natural Farmer goes I have cc-ed Jack Kittredge on this email, perhaps some of your comments and concerns can be used in the next issue in the letters to the editor section.

Regards, Doug

Hi Dan,

Thanks for the strong letter. I have asked Bryan if he would like to respond. I plan on printing your letter and any response I get from Bryan in the next issue. This is exactly the kind of discussion I want to foster on issues like this.

— Jack

Dear Jack,

I didn’t write the letter to start an argument with the author. I wrote the article to let you know how disappointed I was that NOFA would even print such a piece. If you are going to print my letter I ask that you print it in its entirety (perhaps omitting the very beginning which is addressed to Caro and Doug). Please do not pick apart the letter and only print the pieces.

Dan Jaffe Wilder

Thanks, Dan,

I wouldn’t pick apart your letter and not let it speak for itself. That is not how I have used this position in all these years.

But I am not so ready to declare the matter of invasives settled, either. I think calls to avoid topics because they are “settled” can be a way of censoring and I have a strong aversion to that. I have not heard from Bryan, but my hope was to let him reply to your statement that the issue of invasives is settled and not deserving of discussion. It looks like we need to decide that question before we decide to take on the main topic or not. If he does not want to do that, then I’ll publish your letter by itself, give my observations, and invite responses.

I don’t often get much feedback from readers and I greatly appreciate your taking the time to do so, even if you didn’t like the job I did!

— Jack

Dear Editor,

I wish to express my concern in the choices of articles published in the Natural Farmer Summer 2020 Special Supplement on Invasive Species. I am specifically disappointed in the glaringly incorrect information presented in the “Invasion of the Turnips” article by Bryan O’Hara.

I appreciate wanting to post articles of different viewpoints, however, there is a difference between opinion and truth. Would NOFA ever consider publishing an article about a different view on herbicides, considering any benefits of using them? I doubt so, which makes me wonder why you would post an article with wrong information about invasive species.

1.     The author addresses observed “die-outs” of various species, stating that “Often disease is blamed for the die-out and humans fail to consider the environmental conditions that were underlying the cause” and follows to state the examples of Chestnut and Elm. American Chestnut was decimated by a pathogenic invasive fungus introduced by humans from Asia over a century ago, with nothing to do with the environmental conditions. You can read all about this from The American Chestnut Foundation as well as from Columbia University specifically about the pathogenic fungus. Same situation with American Elm and the invasive fungi that cause Dutch Elm Disease, explained by so many respectable institutions such as UMass Extension and The Morton Arboretum. While I can appreciate that environmental conditions can be overlooked, these two glaring examples are of the decimation of two dominant trees in North America by invasive species brought to North America by humans.

2.     The section about promoting wineberry, even though the author was told not to, is foolish. To think it is not invasive on their property (cannot establish) and therefore not invasive at all does not take into account the places where wineberry has displaced native ecosystems. Farmers and gardeners cannot apply this logic to invasive plant species, it will only cause negative effects to surrounding natural areas.

3.     The caption about Garlic Mustard is completely incorrect, as you can read in this scientific review paper on garlic mustard, it inhibits soil mycorrhizae via allelopathic chemicals and does not benefit the soil. Multiple scientific studies have proven garlic mustard harms our native ecosystems and plants. The Stinson Lab at UMass Amherst that specifically studies garlic mustard and it’s interactions with the native ecosystem, and their findings show that “garlic mustard disrupts symbioses between mycorrhizal fungi and native plants (Stinson et al., 2006), and thereby alters plant composition and successional trajectories in its new range (Stinson et al., 2006; Haines et al., 2018).”

Publishing mistruths on invasive plants species, specifically those that have been scientifically shown to have negative effects on our native ecosystems, undermines all the hard work of conservation organizations that preserve land and conduct ecological restoration. This includes organizations such as land trusts who work to heal the land by setting aside open spaces (including those for local agriculture) and removing invasive species.

I am disappointed that an organization I currently support would publish such misinformation. NOFA needs to vet what they publish as many people look to NOFA for truth, not for misguided opinions. Otherwise, NOFA will never get the support and recognition of the general public on the importance of organic farming when publishing wrong information and opinions as truth.

Laney Widener Wilder

Hi Laney,

Thanks for writing. I get few enough responses to the journal that I enjoy each, even if critical!

I will send your letter to Bryan and give him a chance to answer your charges by publishing both your letters. If you want to continue past that, I am happy to consider more letters on the topic if there is still new information to advance. If he does not want to defend the article I will publish yours anyway. I don’t know how to enable a fuller discussion than by giving each of you the chance to source your information and argue from cited facts to your different conclusions.

You ask if NOFA would publish an article considering the benefits of herbicides. That is a particularly red flagged issue for organic farmers because the National Organic Program specifically prohibits synthetic herbicides as an organic method. So any article promoting them would have to carry a strong disclaimer that their use would forfeit certification for three years on the adopting farm. But that said, as editor I would consider an article promoting their use in an issue devoted to discussing their pros and cons. How better can you demonstrate the value of something than to compare it to alternatives? It seems like a useful format to have proponents of a system make their case and opponents make their opposite one. If we are not sure enough of our views to feel that we can win any fair competition for ideas, we should not be publishing. To my mind, too many institutions now refuse to give space to ideas they don’t like, calling them “dangerous”, “hurtful”, “in violation of settled science”, etc. Ideas which are not allowed to be heard have a propensity to remain underground and spread out of sight. If you don’t like something, I figure, the best weapon to use against it is the bright light of the sun.

— Jack

Dear Editor,

I am a recent follower of NOFA, having attended my first NOFA conference last summer. I really enjoyed the programs I attended and I am eager to attend the upcoming virtual conference. I am a horticulturist with over 40 years of experience working in native plant gardens. I help to protect land through my local conservation commission and help to steward that land with my local land trust. I have a lifetime of experience working on the land. I read an article in the summer 2020 issue of Natural Farmer “Invasion of the Turnips” by Bryan O’Hara. I admire Mr. O’Hara for donating and providing turnips for his neighbors and his dedication to raising safe, abundant food on his farm. However, I completely disagree with his assessment of invasive plants.

Invasive species (plants, insects, germs, diseases) are a result of introducing species to habitats where natural predators do not exist. Species in this situation have an opportunity to take over and spread rampantly if conditions are right. Not all species that are introduced become invaders. But when invasive plants (and insects) take hold of an area they become a threat to our landscapes. They invade natural ecosystems and reduce biodiversity which is critical to sustaining all life on earth.

Barberry (Berberis thunbergii) and winged euonymus (Euonymus alatus) leaf out early in the forest and rob native spring ephemerals of sunlight, thus preventing them from being able to germinate, grow, flower and produce seed. Garlic mustard (Alliaria petiolata) can be used as a food in salads or made into pesto, but in nature there are three species of native butterfly that lay eggs on this plant expecting it is a good host plant. Their larvae do not survive to maturity because the garlic mustard is toxic to these butterfly larvae. Alliaria is also allelopathic, meaning it exudes chemicals through the roots which reduces the growth of mycorrhizae in the soil favoring garlic mustard and to the detriment of our forest trees. Japanese knotweed (Fallopia japonica) is another species which is edible, yet it is rampant across the landscape. It supports no native wildlife and efforts to control its spread take years and persistent efforts either physical or chemical. Bittersweet (Celastrus orbiculatus) climbs trees and kills them by twining around the trunks and strangling the trees it grows on. And these are just a few of the species which are rapidly changing our landscape. If anyone believes that these invasive species can provide for humans or agriculture, individuals growing these plants need to be exceptional stewards to keep them from spreading onto other properties and into natural habitats. This is a very challenging job.

Although I do not believe, nor to I advocate for, complete control of invasive plants, I believe that we must remove invasive plants where we can. Controlling them is vital to preserving our landscapes. Human intervention is necessary to aid ecosystems when these plants take hold. I do not advocate for the use of herbicides, there are many non-chemical ways to battle invasive species, but a battle it is. As farmers we rely on native pollinators, native predators and native ecosystems. Native plants provide food for humans and wildlife alike, they support many species including the beneficial insects that protect our crops.

Your publication is used by many as a guide to better living and living in harmony with nature. Prior to publishing an article it is the editors’ responsibility to fact-check and edit articles. Please do not spread false information that invasive species are ‘just a point of view’, or encourage people to plant species that have been identified as plant invaders through scientific study and observation. As a land steward I have seen what these plants have done to our native landscapes. I appreciate unique points of view, but ignoring current ecological science is irresponsible.

Leslie A Duthie

Dear Jack,

Thank you for giving me the opportunity to respond to these letters. Thank you also to the Wilders and Leslie Duthie for providing the opportunity to further the discussion on “invasive” species. The letters provide strong support to my article’s relatively mild statement that the concept of an invasion of weeds appears to be linked to the human separation from the lessons of nature. Some of the lessons that nature shows us include: the importance of human tolerance and compassion, that nature is prepared to provide for itself, an understanding that humans have a limited ability to fully comprehend the complexity of the natural system, that human “truths” are temporal and in constant need of re-evaluation and, of particular importance in this discussion, that humans are part of nature and not separate from it. These lessons, and much more, have led me to gratitude and humility as I work with the creation to further the abundance of life. It has also made me wary of human “battles” against nature.

As I pointed out in the original article, a battle against nature’s “invasives” is a battle against ourselves and nature does well in holding up the mirror so that we can see what we are doing, learn, and adjust our actions. Of course our eyes have to be open to do so. I also pointed out that nature’s timeline is very, very long and therefore nature is not particularly concerned with the hurried human perspective of “weeds” or plants out of place. With this timeline in mind it can also be seen that no human “battle” against nature’s “invasions” has ever been won, nor is it likely that any present battle will prove victorious. Of course there are many examples where humans have been quite detrimental to the life forces in the short term, as well there are also many examples of the benefits of humans to the abundance of life. To be of benefit we may alter the environmental conditions of a given area, including the removal of existing vegetation, yet as nature has consistently shown us, this is best done in a gentle, careful approach where human and nature work together to create a living, thriving environment. War rhetoric is not consistent with this approach, and the battle fury is probably better applied to, say, the forces of Satan, or a spar with a good buddy, than to nature.

The letters received by the Natural Farmer in response to the “Invasion of the Turnips” article have the complaint that incorrect claims were made, and facts were presented which were inaccurate. Yet the article presents no “facts” and very little is claimed. The article is simply a presentation of understanding gained from working with nature. The complexity of nature is very resistant to remaining in the confines of human “facts”, so when writing about nature I generally do not state “facts” and instead present a more holistic, flexible view of human and nature. Claims are similar in that nature has taught “the more you know, the less you know” so all statements about the surety of my knowledge are mild and flexible. This includes statements like “often” (as in, not always) the disease is blamed for the die-out and humans fail to consider the environmental conditions that were the underlying cause. As well with “the concept of an invasion of weeds appears (as in giving the appearance, and thus in need of further examination)to be linked to the human separation from the lesson of nature”. In contrast to this flexible, humble approach the response letters offer an authoritative outlook of being very sure of their “facts” and with this self-righteousness believe they are correct in telling others which plants are acceptable for cultivation, and of course what is appropriate for the Natural Farmer to publish. Thus the letters reinforce the stated appearance of a lack of nature’s lessons.

In terms of the inaccuracies of the letters, Dan Wilder claims “Invasion of the Turnips” makes light of major ecological threats, and though it is true that humor is part of the article, I believe a re-read of the article would reveal quite the opposite. The article points out very serious major ecological threats far beyond the movement of species, and instead of blaming nature for nature’s demise, links the destruction to such things as pollution, war, greed, industrialization, and the unguided human. He goes on to state that I encourage people to plant wineberries. Though I am a proponent of human freedom, as well as vegetation, the article simply states that we attempted to grow wineberries. I would not presume to encourage or discourage other people to grow wineberries, as only the individual would know what is appropriate for their situation. As for our tree “canopy that is thinning for some mysterious reason”, it is far from mysterious. Aside from the observation of the obvious forces of destruction as described in the article, readers can look to much published material on the effects of pollution and nutrient imbalance on plant health if “demystification” is needed. For a scientific outlook, The Nature and Properties of Soil has an excellent chapter on the impact of pollution on soil, and Mineral Deficiencies and Plant Diseases does an outstanding job of illuminating how nutrient imbalances impact plant growth. Both manuals present excellent scientific information without overstatement, and generally stay clear of the reductionist viewpoint.

Carey Widerer Wilder also makes authoritative overstatements in her letter, such as the Elm and Chestnut die-outs having “nothing to do with environmental conditions” and garlic mustard “does not benefit the soil.” Very likely these statements are inaccurate, but it is the surety of the statements that are the most telling of the authoritative stance. When she calls my efforts with wineberries foolish because I “was told not to” is also aligned with knowing what is best for others. Foolish is certainly not commonly used to describe my actions, as the fool is the one who does not pay attention to what is right in front of them. The article “Invasion of the Turnips” describes the opposite approach to life; one of careful, direct observation. In general the only time I find my actions or statements described as foolish is when the person I am discussing a subject with has no better logical or sensible thing to say.

One of the few accurate statements in these letters is that I did not do what I was told by planting wineberries. This is because I never do what I am told by absurd entities, and instead do what my heart, mind (and, in the case of wineberries, my stomach) tell me to do. Nature, god, and spirit help to better inform these decisions, which assist in avoiding the common condition of “fools guiding the fools”.

Leslie Dunthie’s letter also has overstatements like Japanese knotweed “supports no native wildlife”. This is clearly inaccurate, as there are plenty of native beings living in those knotwood patches, especially wood chucks. She also states that farmers rely on “native pollinators, native predators, and native ecosystems”, which is accurate to some degree, but of course we grow mostly non-native crops in dramatically altered ecosystems with the assistance of many non-native pollinators and predators as well.

Thank you again to the writers of those letters, and Jack, for allowing this place for discussion and furthering of differing viewpoints. The Natural Farmer has become the leader in offering such open discussion of difficult topics to the agricultural community. Maybe now is the time for more contentious subjects, such as government regulation of agriculture or, my favorite, weather modification. Maybe a similar format? The history of weather modification, the benefits, the drawbacks…..

Thank you all, love The Natural Farmer.

Bryan O’Hara

Dear Jack,
I would like to agree with other requests to learn more about managing invasive plants. Julie’s comments (in a NOFA/Mass publication) make it clear that invasive weeds in a no-till garden are a problem, but a very different problem than going to war against a hillside of multi-flora rose entwined with bittersweet, buckthorn, and honeysuckle.

Landscaping classes recommend heavy equipment, but that gets costly very fast. We have 3 acres of pasture that had been allowed to go wild on rocky hillsides. We have spent years clearing the plants, but because of the rocks, the only way to maintain the hard work it is by weed-wacking acres twice a year. UGH! Suggestions would be most helpful!!

— Jan Johnson
PS We love The Natural Farmer. I save past issues for grandchildren, to jump-start their science research papers.

Hi Jan,
I am no expert on which kind of animal to use in such a situation, but cows, sheep and goats all come to mind as possible allies in your attempt to manage invasives as well as to do some carbon sequestering and some food production. From my reading and from resources from the Savory Institute, and what Jerry Brunetti used to suggest, I would encourage you to look into a mob stocking arrangement with some animals. Pigs might be of some use too. I think the principles are pretty much the same – concentrate your animals in an area for a short period of time and move them on. If it is a ruminant species, feed them some hay as needed while they are in the specified small amount of land, and if it is pigs, supplement their range diet with more concentrated feeds. Then move them on to a new area.

Some of the really talented animal husbands raise different species together, though I haven’t tried that. Check out the work of Greg Judy. Don’t bring anyone back to a location until the greenery has come back and is in a strong carbon sequestering place. That totally depends on fertility and time of year, rainfall, etc. If you really want to supercharge your pasture, contact Advancing Eco Agriculture and work with one of their consultants to develop approach foliar sprays that will help remineralize your pasture quickly. With three acres, you have some decent space to work with. Good luck. It sounds like a fun project.
— Julie

Dear Natural Farmers,
I am not offering an article but only Information that you might consider useful for your issue on Invasive Species. Some of it might be new to you. You are welcome to use whatever you wish. Thank you for The Natural Farmer.

It might be better to examine the area, what drains into it, what else is growing there, what is the history — what has affected the soil, rather than to react without thinking and to kill.

Connected with the question of what belongs here: In 2019 I attended two meetings in Sheffield re: glyphosate and in 2020, one at the NOFA conference and another in Lenox (Ed Stockman, speaker). At the Berkshire meetings, I recognized people who have applied RoundUp or Rodeo to phragmites for The Nature Conservancy (TNC) for the past 20 years and to roadsides, wetlands, river banks, and homeowner easement properties, to kill weeds, vines, shrubs and trees in recent years. I also recognized homeowners and owners of orchards and farms who have easements with TNC and the Sheffield Land Trust. The local TNC representatives require and/or try to require easement property owners to use glyphosate on invasive species. They send directives by mail and in person.

In the first meeting — a large group, the man who applies glyphosate to Japanese knotweed on the Housatonic River banks spoke way beyond our allotted 3 minutes to argue for the use of glyphosate on knotweed to save native plant life. He referred to ‘scientific’ papers that testify to the safety and beneficial attributes of glyphosate. He was given a meeting of the Great Barrington Conservation Commission to pitch what he does. At the second meeting in Sheffield, half of the very small group were glyphosate advocates and they did advocate. Since then, the five of us who hope for a ban on glyphosate have not asked for another meeting. We are busy in other ways.

Over the past three decades, The Sheffield Land Trust has financed dairy farms that use petrochemical fertilizer etc. on land planted to GMO corn. The Land Trust and TNC collaborate and claim to save land from development. Atrazine and glyphosate have kept the ground bare. This land drains into the Housatonic River. The fields are in view along Rt 7. One dairy abuts Bartholomews Cobble along the river. Others are out of sight but the entire watershed drains into the Housatonic. Thought for the ocean and the rest of the world has no chance.

Local PR refers to the beautiful ‘rural nature’ of the town because of Land Trust ‘protection’ of land. Recently these fields have sent out an increasingly offensive smell from the manure of GMO corn/glyphosate-fed cows. The Land Trust has easements on home properties, orchard and vegetable farms, dairies and woodlands throughout the town and supports the use of glyphosate on weeds and invasive species on those properties. In 2003, the Land Trust took control of a town Master Plan and prevented the inclusion of information on climate change and organic farming. It took control of the local newsletter and has placed members on official town committees. The directors stopped publishing its list of donors in the 1990s. Both TNC and Sheffield Land Trust buy and sell real estate. TNC deals in huge tracts of land around the world. They continue to keep non- profit status, and claim to be environmental and educational. The town of Sheffield rests among rare sweet water wetlands of the Housatonic flood plain where the limestone bedrock and glacial deposits once gave rich soil to the region. The soil and the aquifer are in jeopardy.

Some years ago Mark Dowie, in “Conservation Refugees,” described how the BINGOs (Big International NGOs) have driven indigenous people off the lands that they have cared for and loved for thousands of years. TNC is one of the BINGOs.
–Dorothy Weaver

Thanks for your thoughts on invasives and concerns about glyphosate and the groups that promote it. This is indeed a very controversial topic even for many organic advocates. It seems we have gotten so used to having our way with Nature, bending it to our wills, that we have forgotten our proper role on this blessed earth. I hope that the current public health emergency, product of a normal but invasive feature of Nature such as an infectious virus, is teaching us some lessons about a better way to fit in here.

This issue, addressing some of these hard questions of diversity and proper balance, is designed to give readers useful information and perspectives to cope. I hope we continue to deserve your thanks!
Jack Kittredge