Non-Native Bullies Shake Down Local Flora


Tornadoes, an earthquake, the edge of a hurricane–all in Massachusetts, all in one summer. This is unusual, as are the record number of recent floods, droughts and storms across the planet. The natural world is in a climate change flux and even the lush, green foundation beneath our sandy feet is shifting—invasive species are quickly and quietly changing the local landscape.

Tim Boland, executive director at the Polly Hill Arboretum in West Tisbury, calls plant invasives "ecosystem changers, plants that do not play well with others, bullies. Garlic mustard changes the soil chemistry so much they inhibit natural plant growth. Invasives will now have longer seasons to fully form fruit. They were annual and now we will see plants that can over-winter and produce more seed."

At Felix Neck Wildlife Sanctuary bittersweet "is strangling milkweed, where butterflies lay eggs. No milkweed means no more butterflies," says executive director Suzan Bellincampi. "It is currently our biggest problem, it's a huge challenge in the fields, the trees, it's killing things, it would strangle the children ..."

Invasive species are moving north as temperatures rise. Global warming, according to the National Wildlife Federation's Gardner's Guide to Global Warming, "will contribute to a considerable expansion of invasive, nonnative plants and animals, which are able to take advantage of weakened ecosystems and outcompete native species. Higher average temperatures and changes in precipitation patterns will enable some of the most problematic species, including kudzu, garlic mustard, purple loosestrife and Japanese honeysuckle, to move into new areas. In addition, global warming will contribute to more severe infestations and habitat damage from both native and exotic insect pests ..."

Mr. Boland notes that only a small percentage of plant species are "devastating, that can really change ecosystems." His list of the 10 worst Vineyard offenders: black swallow-wort, garlic mustard, Phragmites, Eurasian water-milfoil, mile-a-minute, common buckthorn, Japanese stilt-grass, porcelain vine, spotted knapweed and purple loosestrife.

Ms. Bellincampi adds that kudzu has arrived on the Island. Kudzu vines can grow more than a foot in a single day, shading out and overgrowing other plants. "Invasives leaf out earlier, get a jump start, and more so with warming," she says.

Mr. Boland explains that "some invasives were introduced by the U.S. Department of Agriculture for erosion control and wildlife management–multiflora rose, Russian olive."

Brian DeGasperis, a coastal ecologist for The Trustees of Reservations, says of invasive species: "We can't change their moving habits, they are taking their best opportunity to survive in the habitats that they need. Phragmites replaces cattails in brackish areas and create a different habitat that is utilized by different insects and birds and does not benefit the native flora and fauna which can't feed on those different species."

Plants aren't the only invasives. Moths and beetles are damaging, at times decimating, Island trees, although not all are invasive. Some global pests are not on the Vineyard yet but have the potential to arrive, according to Mr. Boland, including the emerald ash bore and pine beetle. Polly Hill has set traps to monitor for potential new species. Meanwhile, marine invasives are damaging shellfish habitat and aquatic ecosystems.

The invasives are outcompeting native species, generally defined as those that exist in a certain ecosystem as the result of natural processes, without human intervention, those that in North America preceded the arrival of Europeans. Some common native Island plants and shrubs are goldenrod, milkweed, butterfly weed, low bush blueberry, and beach plum.

The Island is also home to many nonnative but naturalized species that have been introduced and tend to fill in niches, acclimate fairly well, and don't harm local ecosystems. Joan Hughes, a horticulturist and chairman of the Oak Bluffs conservation commission, notes that "a lot of non-natives came here for specific reasons: herbal, medicinal, fruit and food plants–for humans needs." Some, she adds, "come from similar climactic conditions. That's why we have a lot of far eastern plants on the Island. They are not outcompeting the natives and have the necessary food value."

To Ms. Bellincampi definitions are irrelevant. "What is relevant is what could do the most damage to your area," she says.

Conservation land managers in the past have tried to keep in check as many invasive plants as possible, but global warming has changed the rule book.

"We are inundated with new ones," says Mr. DeGasperis. "Before we were doing as much invasive control as we could but now the problem is a lot more extensive; now the goal is early detection and rapid response–minimize and eliminate threats, protect rare and unusual species. Monitor it, see it, and get it out."

The goal is less clear cut for land use managers. Conservation commissions are charged with administering the Massachusetts Wetlands Protection Act. One goal of the act is to protect coastal banks (and as a result, the homes above them) from flooding and storm damage. Vegetation helps stabilize coastal banks. If existing vegetation is invasive but stabilizing, is that a bad thing? Should it be torn out–thus destabilizing the bank–so that natives can be reintroduced? "There are no absolutes," says Ms. Hughes. "Conservation commissioners have to separate any advocacy and personal points of view from their regulatory role. Everything in life involves some compromise."

As species change locales for the sake of survival, the New England Wildflower Society, in a policy statement on climate change, asks: "What is a natural community? . . . How do we accommodate shifting species and processes? . . . How do we decide which plants deserve protection as rare native plants? . . . Because of changes in the composition of ecosystems, and the species that make up these ecosystems, plant conservation will need to adopt a different paradigm. The concept of 'native to New England' (or a state within New England) will change as native plants from the South move northward into our region. Plant community concepts will likely need revision as assemblages of plants become rearranged."

An ecological war of words of sorts has broken out in the mainstream press about natives versus invasives. The Vineyard Conservation Society is addressing the issue in their Conservation Almanac with a story titled "Invasive Species, Ecological Bullies or the Scapegoat of Nativists?"

Still, everyone tends to agree that the most damaging invasives require early detection and rapid response.

The principal way invasive plant species reach the Island, according to Mr. Boland, "is through imported soil, badly damaged soil that is not composted," as well as "bad seed purchased by farmers to increase the nitrogen capacity of the soil. It's important to educate landscapers and gardeners. Limit importation, limit spread." His code word is vigilance: "Watch out for tainted soils."

Like so many others, Ms. Hughes says she has more questions than answers. But every homeowner can make a difference. "You can control invasives in home landscapes, on a small scale," she says.

At Polly Hill, much work is under way to study and redefine the issue. "We are observing 60 years of Polly's collection of trees," says Mr. Boland. "We can see which ones will be problematic very early. We have removed about 100 plants and trees. Polly Hill is a living lab of safe plants to use."

At Felix Neck, Ms. Bellincampi says: "We are often asked, 'What should I be planting?' Know your plants. Know your basics. If something doesn't look right, find out what it is, ask. People bring plants to Felix Neck all the time to ask what it is. Keep an eye out or it will take over your whole neighborhood."

The Gardener's Guide to Global Warming notes: "Gardeners have an important role to play to minimize the threat of invasive species expansion by removing invasive plants from the garden and choosing an array of native alternatives." And, they add, encourage local nurseries to stock native plants and avoid invasives.

Ms. Bellincampi points out that "plants and wildlife are all connected, and planting for wildlife is where the rubber hits the road."

The environment is our foundation. It provides life, food, health, beauty, recreation, tradition, economy. It is in disarray. Fossil fuel consumption is warming the world, disrupting life cycles from plants to food to humans. Our local conservation professionals agree that what you plant–and eradicate – in your own yard can make a difference. And we can all do more – seek alternatives to fossil fuel consumption. Green is a good word–for the environment and the economy.

This series of 14 essays about climate change was published in the Vineyard Gazette over a period of seven months in 2011. It appears here with permission. Copyright Vineyard Gazette. All rights reserved.