Environment / Unusual Organisms

Thomspon pond is about a ten-minute drive from the modest Dutchess County house Kiviat shares with his wife, Elaine Colandrea, a massage therapist. The pond is famous for the floating mat of vegetation on its fringes, unusual enough to have prompted the Nature Conservancy to buy it and the surrounding land in 1958. It’s a perfect example of a glacial pond. And a perfect place for Kiviat to show a visitor how loosestrife behaves in an undisturbed setting.

Kiviat has been visiting the site since he was in his 20s, snapping photos, drawing pictures, taking notes. He’s spent whole days in this and other wetlands of Dutchess County, sitting motionless in a canoe or on the bank. Everything from muskrats to bog turtles attracts his attention, and he had accumulated notebooks of observations on loosestrife before most people had ever heard of it.

These days, Kiviat has environmental studies classes to teach and grad students to supervise, as well as his work as executive director of Hudsonia, a nonprofit research institute, so he can visit for only a few hours at a time. Still, like an old-fashioned country doctor checking on patients, he continues to make rounds. He knows these patients so intimately that even the most subtle changes stick out. “I’ve been coming here for 25 years,” he says, piloting his dilapidated Toyota over back roads leading to the pond, “and there’s not a lot more loosestrife now than there was then. Some, but not a lot. You hear about the plant being so aggressive, but the landscape here hasn’t changed much.” In fact, the places where loosestrife has expanded are the places where humans have encroached on Thompson Pond. One is along a road that cuts the pond in half—the plant seems to like the salty runoff from de-iced blacktop. The other spot is near a feedlot for cows.

To understand the role of loosestrife in the ecosystem, Kiviat believes he must see it when it’s dormant. “The marsh can be a nasty place in winter, and it can be hard for animals to make a living,” he says. “A big plant like loosestrife, which takes two years to die back, might provide important shelter for something.” This nasty March morning a bitter wind rattles the cattails, and six inches of wet snow obscure the faint trail around the pond. Not that Kiviat seems to mind. He lingers to admire the wintry landscape, to puzzle over some animal tracks, to listen to red-winged blackbirds, all as if it were a balmy May afternoon.

The real object of his three-mile walk around the pond is to counter the notion that loosestrife creates a dead zone where no native plant can survive and no native animal sets foot. There are many small ways in which the plant is being integrated into the ongoing wetland life. For instance, he notices Virginia creeper climbing on the dead loosestrife stalks, which remain standing for two years. He spots three or four bird’s nests, including a grackle’s nest suspended between a loosestrife stalk and a swamp rose. “I’d say that’s three-fourths on the swamp rose and one-fourth on the loosestrife,” he says, scrupulously refusing to overestimate its importance. A chickadee flits by and perches briefly on a loosestrife stalk.

A little farther on he comes across unequivocal evidence that something is putting the loosestrife to positive use. Kiviat slits open a stalk with his pocketknife and a bright yellow insect larva gleams inside the pithy core. “That’s a Mompha,” he says, referring to a moth genus. “I see these fairly often, but because I’ve never seen the adult form, I can’t get it identified. For all I know, it could be a previously undescribed species.”

Discovery of a new insect species on purple loosestrife is unlikely, Kiviat says, but not impossible, given how little attention people pay to loosestrife ecology. Take the butterfly: The standard guide to butterflies of New Jersey says that only cabbage butterflies, the lepidopteran equivalent of trash fish, use loosestrife. But Kiviat, sounding slightly aggrieved, says that New Jersey loosestrife is visited by “big, beautiful, important butterflies—monarchs and tiger swallowtails and silver-spotted skippers.” A few observers, writing in obscure journals, have reported seeing the moth Biston betularia on purple loosestrife in Manitoba. The species has gained immortality in high school biology texts for switching colors from peppered to dark gray in the grimiest days of the industrial revolution.

Later, thawing out over a tuna melt and coffee in a local diner, Kiviat says the size of a plant’s insect fauna isn’t a matter of its popularity, but of its future. The more native insects an invasive plant attracts, the more chance some insects might decide to eat it. And if that were to happen, it could slow, or even stop, the invasion.

There are, says Kiviat, good theoretical reasons to believe that a problematic invasive might settle down without human intervention, though he concedes that it probably wouldn’t happen on a schedule that would make humans happy. Loosestrife has been here for more than 200 years; if something wanted to eat it, there has been plenty of opportunity. Yet the literature on invasives does record a few happy accidents: cases in which an invasive exotic met a native insect that said “Hallelujah!” The multiflora rose, for instance, spread unimpeded from the East Coast to the Rockies in a matter of decades, then encountered a mite carrying a disease of native mountain roses. Some of those mites switched hosts and are now marching east, destroying multiflora as they go.

The invasive exotic Eurasian watermilfoil, a likely escapee from home aquariums, began clogging waterways up and down the East Coast in the 1940s. A few years ago an alert biologist noticed unexplained declines of the invader. She investigated and learned that a native aquatic beetle had discovered the invasive, found it more palatable than the closely related native milfoil that had previously formed its diet, and started munching. Now when the weed becomes a problem, biocontrol specialists just beef up the beetle population.

Of course, Kiviat’s pleas for a wait-and-see approach to loosestrife may become moot if plans for insect biocontrol succeed. Since 1985, researchers centered at Cornell have been studying the possibility of controlling loosestrife by importing some of its European predators. After screening 100 or so insects that eat the plant in Europe, the researchers settled on 4 candidates—2 leaf feeders, a flower feeder, and a root feeder—deemed unlikely to misbehave in a new environment. (One test: The insects starved to death when offered anything but loosestrife to eat.) To date, the group has released more than 3 million insects on more than 1,200 loosestrife sites in more than 30 states.

The results are just now being tabulated—it can take three to five years for an insect population to get big enough to do major damage—but preliminary reports indicate success. Yet not even the most enthusiastic biocontrol freaks, as Kiviat sometimes calls them, think insects are the whole answer to loosestrife management: Hand removal and other methods will always be necessary.

Even if biocontrol were to eliminate loosestrife, there are plenty of other invasives to which Kiviat could turn his attention. He never misses a chance to visit a certain clump of reeds called phragmites in a pond in Central Park; he stops there when he’s in New York City the way some people make a point of popping into Zabar’s. Though deplored as an invasive, the plant has been in North America for 3,000 years. “People love that phragmites,” he says. “It looks nice, and the fact is, the birds use it constantly. Last time I was there I counted eight species in half an hour.”

Kiviat insists he’s not an apologist for the aggressive habits of loosestrife or other invasive plants. “Look, if you see a single purple loosestrife in a conservation area, I think you should pull it out by the roots and go back every year until it’s gone. There are situations where these plants are the enemy—but not in every situation.” Besides, he says, “sometimes when you get to know your enemy, he turns out to be your friend.”