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Invasion of the Habitat Snatchers

Invasion of the Habitat Snatchers

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Genevieve Rajewski covers animal issues, food, and agriculture for publications such as The Boston Globe and EdibleBoston.

This article originally appeared in the Spring 2014 issue of Special Places, The Trustees' member magazine. To subscribe, join The Trustees today.

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The Trustees & friends work to stay a step ahead of invasive plants.

By Genevieve Rajewski

Rene Wendell, a conservation ranger at Bartholomew’s Cobble in Sheffield, has worked to protect this incredible landscape and inhabitants for more than a decade. In that time, he has won – but also lost – countless battles to the reservation’s worst nemesis: a cast of invasive plants.

“The Cobble has National Natural Landmark status because of its biodiversity,” says Wendell. “It’s a horticultural hotspot with lots of rare and significant plants. But the conditions that make this possible also make the Cobble really inviting for non-native plants.”

It may seem strange or even frivolous to think of a plant as an enemy. After all, plants aren’t inherently good or evil – they are just plants, doing whatever they are genetically programmed to do. But when introduced to a non-native environment, a plant sometimes can dominate and disrupt a natural area to the significant detriment of other plant and animal life.

Take garlic mustard, an invasive plant found at the Cobble, for example. This herbal ground cover, believed to have been brought by settlers to the U.S. from Europe for food and medicinal purposes, chokes out other plants that live on the forest floor. Garlic mustard not only outcompetes other plants for sunlight, water, and soil nutrients, it actually releases a chemical that makes the surrounding soil poisonous to soil fungi crucial to native plant species.

Compounding these problems is invasive plants’ lack of natural predators. For example, although 69 plant-eating insects have been found on garlic mustard in Europe, less than a dozen have been found on the species in North America, according to a 1998 report by the Centre for Agriculture and Biosciences International (CABI), a not-for-profit agricultural research organization. This not only allows the plant to quickly outnumber and further dominate other plant species, it also hurts all members of the food chain, notes Wendell.

“Invasives have no value to the ecosystem,” he explains. “If there are no caterpillars eating these plants, what are baby birds going to eat? No wonder many of our native songbird populations are declining.”


The good news is that, when it comes to invasive plants, “the real thugs have been banned in Massachusetts for some time,” says Patricia Bigelow, president of Bigelow Nurseries and a member of the Massachusetts Invasive Plant Advisory Group. “You aren’t going to stumble across any of them for sale.”

This has allowed concerned parties throughout the state to focus their attention on stopping or at least better controlling the spread of habitat-harming plants.

After a study of the plants, wildlife, and habitats they protect, The Trustees determined that about half of the 111 reservations are high priorities for controlling invasive plants.

“Invasive plants are so common on the landscape that we can’t target all of them, everywhere, on our properties,” says Russell Hopping, The Trustees’ Ecology Program Director. “We don’t have the resources to do that on 25,000 acres.”

In 2012, The Trustees were able to treat or monitor 73 percent of those top-priority natural habitats.

Staff and volunteers helped eliminate or reduce existing populations of invasive plants in many ways: by hand pulling the weeds, carefully administering herbicides (done by licensed staff only) and using government approved biological controls such as an imported beetle that eats purple loosestrife, a beautiful purple plant that has overrun local wetlands.

The Trustees’ most cost-effective and successful way to control invasive plants has involved preventing them from becoming established in the first place, notes Hopping.

The Trustees have emphasized training both staff and volunteers on how to recognize invasive plants that have yet to appear in certain areas in hopes of detecting their arrival early enough to keep them from gaining a foothold. When Hopping found the first small clump of black swallow-wort, a milkweed-like plant that ruins habitat important to monarch butterflies, on Weir Hill in North Andover, The Trustees were able to completely eradicate it within two years. A volunteer at the Charles River Peninsula in Needham caught the arrival of Japanese stiltgrass in time to keep it from shading out other plants and hurting insect populations.

Of course, The Trustees properties neither exist in a vacuum nor serve as the only important habitats in the state. “We realized we can’t just mobilize people to work on our properties; they have to be on the lookout for invasive plants in their own communities,” explains Trustees regional ecologist Julie Richburg, Ph.D. “Western Massachusetts in particular has so much open space that is privately owned family forests or farms.”

The Trustees helped initiate the Westfield Invasive Species Partnership to develop more public knowledge and a citizen corps of earlydetection spotters for the Westfield River watershed, where it has four reservations. (They also are involved with a similar group in the Sudbury Assabet and Concord Rivers Watershed, which is home to the Old Manse.)

The Westfield group started by hosting community-oriented workshops on how to identify invasive plants and eventually dug a little deeper to spread the word via “Tupper Weed” parties. For these informal events, the group would send invasive-plant experts to a party hosted by a local resident, who had also invited a group of friends or neighbors. As the partygoers enjoyed snacks and drinks, the botany experts would walk them around the host’s backyard or neighborhood to point out invasive plants present in that actual landscape and show examples of other species that soon may arrive to the region.

Given invasive plants’ pervasiveness throughout Massachusetts, Richburg says she understands why some people may be discouraged by the prospect that it’s a lost cause. However, she explains that anyone can make a real difference by picking their battles wisely.

“Once you start learning about invasive plants, you could get depressed by seeing them all over the landscape,” says Richburg. “But even if there is garlic mustard all over the place that you can’t control, you still can keep it from getting into your yard or park. And you can help plant species that offer a diverse habitat for the native species you love.”

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Genevieve Rajewski covers animal issues, food, and agriculture for publications such as The Boston Globe and EdibleBoston.

This article originally appeared in the Spring 2014 issue of Special Places, The Trustees' member magazine. To subscribe, join The Trustees today.

Join Us
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