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An Insidious Invasion in Illinois BY BURKE SPEAKER
As a plant biology professor at Southern Illinois University in Carbondale, Philip Robertson has a deep appreciation for the unique complexities and magnificent aspects of plant life. He understands the intricate life cycles of trees and plant species, and reserves respect for the vegetation he diligently studies. So it may seem odd, almost paradoxical, to know he has spent four years and garnered nearly $20,000 worth of funding to destroy one very harmless-looking type of plant. Robertson's nemesis is the Japanese honeysuckle, a non-native invasive species that looks like nothing more than another ordinary vine, possibly even a potential landscaping plant. And it could be a landscaping plant if you want it running amok on the landscape within a few years, which is exactly what happened at Robertson's university. "We're fighting against some very fast-growing exotics," he said. "And they grow over everything."
The SIUC campus houses Thompson Woods, an isolated 15-acre oak and hickory forest suffering from the honeysuckle's encroachment. The invasive plant, likely originating from seeds in bird droppings, is clogging the forest floor, making it nearly impossible for further oak or hickory growth. Instead, shade-tolerant beech and maple trees are thriving, and what oak seedlings do make it past the choke hold of the vines are in a life and death struggle for sunlight— and losing the battle. In effect, the woods are being altered as the gangly-looking vines blanket the area, yielding an entirely different—and unsightly—forest composite. "We're slowly starting on the uphill climb," Robertson said, referring to the lengthy, arduous process of removing the exotics by hand and herbicides. "But we're barely out of the bottom."
Kudzu can grow up to a foot a day and will cover buildings, trees, poles or anything else that it can adhere to. (Photo courtesy of Bill McClain) Robertson's plight is a fragment of a nationwide quandary plaguing biologists, ecologists and natural resource agencies: How to handle exotics spiraling out of control— snuffing out biological diversity, altering ecosystems and costing the nation billions. A recent Cornell University study concluded the national economic impact for invasives is $137 billion annually. The matter has become so urgent that a national Invasive Species Council has been formed to study eradication and prevention strategies. The arrival of invasive species— defined as any organism not native to the region, whose introduction causes economic or environmental harm, or harm to human health—is faulted mostly to man. Humans introduce them either by unwittingly harboring the exotic hitchhiker or by foolishness, bringing the species to an area because of its perceived helpfulness or aesthetic quality. Today, according to the U.S. Fish and Wildlife Service, roughly 6,300 invasives pervade the land— with more identified weekly— sparking ecological and economical degradations at an accelerating rate, and making them one of the toughest challenges facing resources in the nation. Illinois is no exception. Invasive species are littered throughout the state, with nary a region escaping unscathed. Illinois' invasive enemies include: Zebra mussels: Originating in the Great Lakes and now established in the Mississippi River system, zebra mussels have effectively shut down electrical utilities by clogging the water intake pipes of industrial and municipal water plants, causing millions of dollars in damage. A native to Eurasia, hitching a ride to America in the ballast water of oceangoing ships in the 1980s, zebra mussels form dense colonies on everything from power plants to boat motors. Zebra mussels have altered the Great Lakes' ecosystem by removing plankton and using enough oxygen to stress native fishes and aquatic insects. Kudzu: A Japanese migrant that was deemed an "agricultural miracle" in 1945. By the 1980s, when the U.S. Department of Agriculture realized it had erred in its promotion of the exotic, the species covered nearly 7 million acres in the south, invading valuable cropland and covering everything in sight. Kudzu, which can grow up to a foot daily, now is found in 22 Illinois counties. Researchers are concentrating funds and time trying to contain the omnipotent expansion as it damages cropland and shrouds everything in its path. Asian long-horned beetle: An insect that in the past two years has claimed the lives of more than 1,000 hardwood trees in northeastern Illinois. The sole method of containment is to quarantine and destroy the infected tree, leaving residential areas with barren landscapes. Last summer, city, state and federal officials spent more than $1 million for the clearing and replacement of infested trees, and the Illinois state legislature has allotted $250,000 to the Department of Agriculture for similar management. Further surveys and tree removal likely will continue for five or more years at a cost of several million dollars before it's known if elimination attempts succeeded. But as these and countless other invasive species infiltrate Illinois with rabid intensity, state officials are hammering back. The Department of Natural Resources formed the Interdisciplinary Committee on Invasive Species in 1999, to which the state legislature doled out $250,000 for site-specific ecological restoration and for research into possible annihilation or control. This was followed by another $250,000 in 2000. While impressive, the amount is miniscule compared to the ever-growing, multi-million dollar price tag that comes along with the invasive species' arrival.
Adult Asian long-horned bettles are large, conspicuous insects with 40 or so white dots marking their skinny, coal-black bodies. (Natural History Survey photo.) "As an agency, what we're concerned about on our lands is that it's becoming more and more costly to handle these invasives," said workgroup chairman and Illinois Natural History Survey Chief David Thomas, who projects a similar national trend of cost surges in controlling invasive species. "We'll be spending a lot more money and time on these things in the future." Presently, much of the 15-member committee's time is spent organizing. The group submitted a state management plan for aquatic nuisance species to federal officials, who awarded a grant of $80,000 for five years to continue research and management and to hire an aquatic nuisance species coordinator. The committee also is compiling a statewide inventory of its exotics, as there currently is no documented number of Illinois non-native species. "I think that's quite a statement right there that we don't even know how many we're dealing with," said Thomas, who co-chairs a workgroup for an advisory committee to the national Invasive Species Council. "There are 50 to 60 species that are really problematic, though, and we've just learned to live with others—like the sparrow, common carp and Queen Anne's lace that now are part of the landscape." Historically, invasive species are well ingrained in the environment by the time they are earmarked for eradication. Simply put, as they strive daily to control invasive species populations, land managers constantly are playing catch up, and often are unable to do so. In the case concerning the round goby fish, a containment option was missed by probably a little more than a year. The goby, a Russian emigre, first was reported in the Great Lakes in 1990 and since has expanded its range into northeastern Illinois rivers. In its quest for space, the prolific goby outcompetes native fish with its startling numbers and diet on the eggs of other fish. "Their populations are so dense, they squeeze out space from all the other native fish," said Pam Thiel, a U.S. Fish and Wildlife scientist who has tracked goby movement in Illinois waters. "They're like the really bad neighbors who move in—the ones who are your worst nightmare." To combat the unwanted neighbors, the U.S. Army Corps of Engineers initiated construction plans in August 1999 on a $1.2 million underwater electrical barrier—located on the Chicago Sanitary & Ship Canal—to curtail movement of the goby from Lake Michigan into Illinois rivers. But to Thiel's and other researchers' dismay, in October
The spread of the round goby has been a major concern because they crowd out native fish, feeding off their eggs. (Photo by Dan Soluk) 1999, goby were found miles past the proposed site of the barrier. And they're heading toward the Mississippi River, which gives them access to waterways in nearly 30 other states. So can the goby spread be contained? "There are not many options left to do that," Thiel conceded. "The barrier will slow them and prevent other invasive species from moving farther down at least." Like the goby, other alien species frequently dodge containment methods, and overall, it is extremely difficult to bring them under control once they are thoroughly entrenched in the environment. "You have to catch them early," Thomas said. "It's very difficult to eradicate an invasive species once it's been established. We know little about their biology and how they might spread in a new environment, so it's important we detect and eliminate them early." Without early detection and management, workers face a lengthy bout with the invaders. Because kudzu was overlooked as a problem, Department of Natural Resources workers now are laboring non-stop on the removal of this aggressive plant. Repeated treatments of herbicide and selective burnings have shown signs of success. "We're right on the edge of being able to control it," Thomas said. "But whether or not we can get rid of it remains to be seen." Other than by using herbicides, invasive species are being deterred by biological control— using host-specific attackers that destroy the invasive by predation. Robert Wiedenmann, an associate professional scientist at the Illinois Natural History Survey and a member of the state's committee, has worked for five years in the reduction of purple loosestrife with this method. "Loosestrife is a beautiful plant, but it's deceptive because what you don't see is the diversity that was once there," Wiedenmann said. "Once loosestrife invades a wetland, it crowds out native vegetation and makes wetland habitat less usable by a variety of birds, mammals and insects. It crowds out the plants that other animal species require for nesting, food and shelter." The good news is that two species of beetle, introduced to Illinois in 1994 to feed on loosestrife, are showing signs of success. Still, biologists say loosestrife never will be fully removed. "Biological control doesn't eradicate any species, it just gives the natives a chance," Wiedenmann said. And their chances are slowly increasing. Of the 130 statewide loosestrife sites using the biological control method, there are close to a dozen reporting initial success. "In Illinois, this is probably the closest thing we've come to as a success story, and I say this cau-
Purple loosestrife arrived in the U.S. in the early 1800s from Europe, minus its natural enemies, and soon grew unchecked in wetlands. (Photo by David Voegtin)
Garlic mustrad, although pretty to behold, crowds out native vegetation. (Photo by Adele Hodde) tiously because loostrife is not controlled yet," Wiedenmann said. As if the biological diversity abatement and the surging cost of controlling these noxious species aren't trouble enough, the human health risks associated with exotics also are increasing, while researchers scurry to discover all they can about viruses never before seen in this country. An outbreak of the West Nile virus on the east coast last year killed numerous crows and waterfowl, and caused the death of at least seven humans and the hospitalization of 55 more. The mosquito-borne virus, initially detected in New York, is an African native previously unreported in the United States. Illinois officials now fear the virus could make its way into the state. "It's a new virus," said Bob Novak, a medical entomologist who heads the Survey's Medical Entomologist Laboratory. "We don't know how it arrived or know how long it's been here." After an infected mosquito bite, the host can act as a carrier; crows are now known to harbor the virus, and since Illinois has some of the largest American crow populations along the border of Indiana, officials are rightfully alarmed. In response, a DNR task force is developing a surveillance system to monitor state bird and mosquito populations. The group hopes to detect foreign viruses before they become a problem in the state and prevent a broader distribution of the virus if it is found. The group will take blood samples of different birds and mosquitos in varied geological areas and test for the virus. If found, the group will deploy varied management strategies on a site-by-site basis. So what's the outlook for future contamination of foreign viruses in Illinois? "We're learning something new on a day-to-day basis," Novak said. "There's no text and no guidelines for this work. The text is written as we go, and we're learning as we go. We just don't want what happened on the east coast to happen to us." But it could, which is why, on top of surveillance and management of the alien species, state officials are deploying preventative measures, hoping that the more aware Illinoisans are of the impending threat, the less risk of a massive spread. Department workers are blazing forward with several educational outreach programs to inform a large segment of the public that there is a problem. For many, the extent of the problem doesn't hit them until invasives start showing up in their backyard. Currently, DNR is aiding teachers and students in educational projects about non-native species by conducting workshops, seminars and initiating other ventures. Some target fishermen, showcasing ways to avoid an exotic spread by simple actions such as cleaning the boats after use to avoid zebra mussel spread. If education and management aren't continued, the future could be bleak for Illinois. Picture yourself walking through the woods and seeing nothing but Japanese honeysuckle covering everything, or in a garden where instead of bluebells just garlic mustard grows. So as invasive species besiege Illinois, Thomas' committee, along with state and federal officials, continue to battle the onslaught, knowing full well that the future of Illinois' ecology and biological diversity is dependent upon the ongoing research and management. It's a project that has only begun and one that may never be complete. "It's probably too late to stop a lot of the species that already have been established," Thomas said, echoing the words of scientists across the country. "But we're realizing that we need to do a lot more now."
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