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Vol. 6 No. 2

Summer 2012

Africa Package Inside

The Ripple Effect of Invasive Species

Summer 2012 Vol. 6 No. 2

Cover Story: The Ripple Effect of Invasive Species 20 A Clear and Present Danger By Michael Ielmini

22 A Call to Action

By Michael Ielmini, Gail Wallin, and George Beck


Tackling an Invasion


Freeing Islands from Rodents

By Divya Abhat

35 The U.S. Forest Service’s

New Directive on Invasives

By Laura Bies



Reframing the Concept of ‘Invasives’ By Mark Davis

There’s Nothing Benign about Invasions By Daniel Simberloff

By William Pitt et al.

28 Credit: Bob Nichols/USDA

In Focus: African Conservation

40  From Challenge to Hope By Richard Carroll

42 As Goes the Elephant,

So Goes Africa?  By Richard G. Ruggiero

48  The Bushmeat-free Eastern Africa Network By Heather E. Eves et al.

50  Inspired by the Maasai By Lisa Moore

46 South Africa’s

Environmental Pioneers By Madeleine Thomas

rotating features


52  Professional Development

6 7 8 10 14 18

Europe’s Conservationist Hunters By Jessica P. Johnson

54  Education

Training the Military to Curb Wildlife Trafficking By Heidi Kretser

57  Human-Wildlife Connection

Protecting Mexico’s Parrots By Laurel A. Neme

60  Wildlife Imaging

A Day in the Life of a Traveling Feline By Kerrie Anne Loyd et al.

62 Commentary

Leadership Letter Science in Short State of Wildlife Today’s Wildlife Professionals: Erin Myers and Kathy O’Reilly-Doyle

70 Policy Watch

Issues relevant to wildlifers

71 Field Notes

Practical tips for field biologists

74 Society Pages

TWS news and events

78 The First 25 Years

64  Tools and Technology

80 Gotcha!

67 Law and Policy

The Need to Restore Wetlands Protections By Scott C. Yaich

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Credit: © Michael Raimondo/Green Renaissance

Letters to the Editor

The Ongoing Debate over Lead By John H. Schulz et al. A Tool to Bring Back Bobwhites By Theron M. Terhune et al.


Guest Editorial

A History of The Wildlife Society

60 Credit: National Geographic Remote Imaging

Photos from readers

More Online! This publication is available online to TWS members through the membership center on Mouse icons and text printed in blue indicate links online.


Invasives: The High Cost of Indifference By Mark Pfost and Kurt VerCauteren


t one time, wildlife professionals may have been blissfully ignorant about invasive species, classifying “plants” as lawn grass, flowers, trees, or weeds, and putting animals into two groups: species with bag limits and everything else. But those days of ignorance are long past. We see how invasives threaten local, even global, ecosystems, and we need to help create greater awareness about the scope of the problem.

Wildlife professionals must not only prepare to deal with how seven billion people, climate change, and habitat loss will affect native species and habitats, but also how those species and habitats will be affected by a host of invasive plants, animals, and pathogens. While we try to sort out the science, we must also lead by educating a public that may be indifferent. Most citizens probably have some idea of what invasive species are, but the concept may be more abstract than real. We need to change that. Many ranchers already get the “real”: They find leafy spurge and automatically understand that this invasive plant leads to degraded rangeland, less forage, and lost income. The person who watches a cat cross from farmhouse to pasture and makes the connection—dead meadowlark—also gets it. The sooner we get society to see such invaders and make ecological connections, the better. Aldo Leopold wrote, “A thing is right when it tends to preserve the integrity, stability and beauty of the biotic community. It is wrong when it tends otherwise.” This certainly applies to invasive species, because biological intrusions of non-native species tend otherwise. Wildlife biologists, now and in the future, may therefore need to spend inordinate amounts of time trying to eradicate, control, or manage what seems to be an ever-increasing number of invasive species. Many of us have been engaged with these efforts throughout our careers. A quick email poll of members of The Wildlife Society’s Wildlife Damage Management Working Group revealed that 91 percent of respondents now work with invasive species, spending an average of 26 percent of their time so

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engaged. They deal with any number of invasives— whether plants, invertebrates, or vertebrates—doing hands-on control, studying and teaching about invasives, or developing related policy. Likewise, members of TWS’s Invasive Species Working Group work with many invasive taxa. Some deal with mammals such as nutria, Gambian pouched rats, feral hogs, or commensal rodents. Others may work to control reptiles or amphibians (such as bullfrogs, spiny iguanas, and brown tree snakes), or avian species such as monk parakeets or starlings. The majority of working group members may direct their efforts toward invasive plants (such as phragmites, garlic mustard, reed canary grass, and kudzu), while some may work with pathogens (such as West Nile virus, chytrid fungus, or Geomyces destructans). It’s important for our working groups and for TWS in general to take leadership on the issue of invasives because of their high cost, both ecologically and economically. The public needs to understand that controlling invasive species costs U.S. taxpayers billions of dollars each year in prevention, management, eradication, and lost ecological services, and that it’s cheaper to prevent invasions than to turn them back. Fewer dollars could have been spent keeping constrictors out of the Everglades, for example, than it will cost to eradicate them now. We either pay now, or we will pay more later. In the fight against invasives, wildlife professionals are adapting a “One Health” philosophy that recognizes the ecological, economic, legal, and aesthetic interconnectedness of all life. Each ecosystem—with its unique assemblage of flora and fauna—also has a historic connection to the land in which it evolved. Allowing invasive species to degrade, denude, or destroy native species is tantamount to knocking over an ink well on our nation’s founding documents and not caring enough to wipe off the ink. We need to ensure that no one—citizen, policymaker, or politician— can remain blissfully ignorant of the connections between invasive species and the environmental health of each unique landscape.

Courtesy of Mark Pfost

Mark Pfost is Chair of The Wildlife Society’s Invasive Species Working Group and is a Partners for Fish and Wildlife Biologist at Necedah National Wildlife Refuge.

Credit: Justin Fischer

Kurt VerCauteren is Chair of The Wildlife Society’s Wildlife Damage Management Working Group and Leader of the Rabies Management and Ungulate Disease and Damage Projects at the National Wildlife Research Center of USDAAPHIS Wildlife Services.


Joining Forces to Fight an Invasion Erin Myers works with landowners to battle invasive species By Madeleine Thomas

Courtesy of Erin Myers

Erin Myers handles a Burmese python caught during a python patrol workshop at the National Wildlife Research Center in Gainesville, Florida. The workshop, which took place in April, was part of a joint conference between the Florida Chapter of TWS and the Florida Exotic Pest Plant Council. Myers is a member of both.



s a private lands biologist for the U.S. Fish and Wildlife Service’s Partners for Fish and Wildlife Program, Erin Myers has worked to get South Florida’s landowners, local government agencies, and NGOs to see eye to eye on the need for cooperative invasive species management. “It’s hard sometimes,” says Myers, “when a landowner says, ‘Why should I go along with this when the [Department of Transportation] isn’t working to combat invasives along the roadway?’ We’re trying to bridge that gap.”

The Partners for Fish and Wildlife Program is designed for just that purpose. It pairs local biologists with private landowners who voluntarily sign up for technical and financial assistance to fight invasive species as well as improve habitat for protected species. Since Myers joined the program in 2009, she has been helping Florida landowners manage invasive plants like the Brazilian pepper-tree (Schinus terebinthifolius) and wildlife species such as Burmese pythons (Python molurus bivittatus). “It’s hard for [landowners] to manage [invasive species] on their own,” Myers says. “Either they are [doing it] already, and it’s costly, or they haven’t started and they don’t realize how big of a feat it’s going to be.”

The Wildlife Professional, Summer 2012

Myers uses a combination of mechanical and chemical treatments in the field. Most are herbicidespecific for smaller species, and technique-specific for larger, more challenging species to tackle like melaleuca trees (Melaleuca quinquenervia), a species native to Australia. Just one melaleuca can multiply into a thick monoculture of trees, Myers says, which alters essential ecosytems like the Everglades by disturbing the hydrology and health of the overall system. Because melaleuca trees can grow up to 80 feet tall, Myers has to girdle the tree around its base before spraying the base with an herbicidal treatment. For other monoculture-producing species like Old World climbing fern (Lygodium microphyllum), Myers uses a technique called “poodle cut.” She cuts the plant to waist height, pulls the vines away from underlying native vegetation, and then prunes enough of the plant to leave a 10-12 inch gap between the upper and lower portions of the vine. The fern section left on the ground is then topically treated with an herbicide like Glypro.

Renaissance Woman

Myers is also president-elect of the Florida Chapter of The Wildlife Society (TWS), chair-elect of TWS’s Invasive Species Working Group, a member of the board of directors for the Florida Exotic Pest Plant Council, and co-chair of the Florida Invasive Species Partnership (FISP), a post held previously by her mentor, Kathy O’Reilly-Doyle. FISP, which focuses on combating invasives on both private and public lands, originated in 2006 as the Private Land Incentive Sub-Working Group. O’Reilly-Doyle, who served as the sub-group’s first co-chair, assisted private landowners with funding, training, and technical invasive species management as well as promoting partnerships between public and private land managers and state agencies working to help private landowners. O’Reilly-Doyle recruited Myers, who, at the time, was working with USDA’s Natural Resources Conservation Service as the agency’s Florida state biologist. “Basically, I called the busiest and most talented people I knew,” O’Reilly-Doyle says. “Erin was one of them.”

© The Wildlife Society

When O’Reilly-Doyle left Florida in 2008 to take a position at FWS’ headquarters in Virginia, Myers assumed her role as co-chair of FISP. Today, Myers continues to reach out to Florida’s landowners at landowner workshops. FISP has also expanded statewide with the creation of a network of almost 20 Cooperative Invasive Species Management Areas (CISMAs) throughout Florida. Each CISMA encompasses a defined, naturally diverse area— including the Everglades and Florida Keys—and has its own invasive species management and prevention plan tailored to the area and the types of invasive species established there.

“Some people feel that we are wasting money trying to [eradicate],” says Myers, “and again I come back and say, ‘You can’t eradicate, you can only manage.’ If we didn’t do what we’re doing, we’re going to lose our habitat altogether.” She cites areas like Arthur R. Marshall Loxahatchee National Wildlife Refuge, which contains over 145,000 acres of northern Everglades habitat and is at risk of depletion from invasive species encroachment. “I want my children to continue enjoying the native beauty of our unique ecosystems. As biologists, I think we need to continue fighting this battle so we can turn the tide of invasion.”

Madeleine Thomas is the Editorial Intern for The Wildlife Professional.

To find a mentor or mentee, go to http://mentor.

Mentor Kathy O’Reilly-Doyle Deputy Assistant Regional Director, U.S. Fish and Wildlife Service Office of Subsistence Management, Alaska

It was only after Kathy O’Reilly-Doyle noticed invasive species in the backyard of her new Florida home, after a move from Alaska, that she began to pay close attention to the problem. What she thought was property abundant with native flora turned out to be overgrown with invasive species like Brazilian pepper-tree (Schinus terebinthifolius) and melaleuca trees (Melaleuca quinquenervia). O’Reilly-Doyle moved to Florida in 2001 to become a private lands biologist with the U.S. Fish and Wildlife Service’s Partners for Fish and Wildlife Program. Like Erin Myers, O’Reilly-Doyle assisted private landowners with on-the-ground wetland and habitat restoration projects, and learned that invasive species were a common thread when it came to addressing habitat threats. “It was something I was encountering on almost every property and with every landowner in one way or another,” she says. At that time, invasive species management was more focused on individual sites, unlike today’s landscape-scale management approach. “If we treated up to our own fence lines ... it was pretty much all for naught, because those invasive species were going to keep going,” O’Reilly-Doyle says. A Land Ripe for Invasions According to the South Florida Water Management District, more than 150 exotic animal species have been found in the Greater Everglades alone. Invasive species management in Florida became a priority in the early 2000s with the creation of the Invasive Species Working Group—a partnership between federal and Florida state

© The Wildlife Society

agencies to develop a statewide plan to manage invasive species on public lands. In 2006, the Private Land Incentive Sub-Working Group was formed to represent private landowners.

Courtesy of Kathy O’Reilly-Doyle

In April, O’Reilly-Doyle visited habitat restoration projects When O’Reilly-Doyle chaired throughout West Virginia as part the Sub-Working Group, she of her training for the Partners for pioneered two pilot programs, Fish and Wildlife Program. now in most of Florida. The first was a database of all state financial and technical programs to treat invasives, available on The second was a pilot program to create Cooperative Invasive Species Management Areas (CISMAs), now active throughout the state.

According to her mentee, Erin Myers, O’Reilly-Doyle was crucial in launching FISP, which evolved out of the Private Land Incentive Sub-Working Group and offers tips for managing invasives on both private and public lands. “Through her, I’ve learned to facilitate between landowners and land managers,” Myers says. O’Reilly-Doyle believes that invasive species management is only as successful as the cooperation it garners. Now working in Alaska as deputy assistant regional director for FWS’s Office of Subsistence Management, O’Reilly-Doyle lauds Myers for keeping FISP going in Florida. “There’s a lot of energy that’s been built on this,” she says. “Collectively we can have more success if we help each other.”


A Clear and Present Danger The Spreading Threat of Invasive Species

By Michael Ielmini


The Wildlife Professional, Summer 2012

Š The Wildlife Society

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magine summer without fresh corn on the cob because a foreign fungus has wiped out pest-eating bats. Picture mountain streams devoid of native trout because exotic algae have choked the water. Imagine soils sterilized by exotic earthworms, wetlands gone silent as frogs die of foreign disease, shorelines exposed as coastal marshes succumb to voracious exotic mammals, red squirrels starving for hard mast destroyed by an alien tree pathogen. Imagine your land dominated by noxious plants from another continent. This is not a drill. Such transformations are occurring right now as invasions of harmful exotic plants, pathogens, animals, and algae silently and steadily find their way into new ecosystems across our continent. These invasive species represent a clear and present danger to the health, functionality, and sustainability of North America’s aquatic and terrestrial ecosystems and the native plants and animals they sustain. The proportional impacts are mounting daily, and human activity is largely to blame as people—intentionally or not—transport non-native species rapidly across the globe. The term “invasive species” has sometimes been misinterpreted and misused, even by some welleducated ecologists. The general consensus is that a species is “invasive” when it is both exotic to the place it invades and harmful—to the environment, human health, or the economy. By definition, then, not all exotic species are bad. Likewise, when some native species become overabundant they can become “native pests,” causing havoc in their native ecosystems. Some species that are native (endemic) to one region of the continent may invade other areas of the same continent where they are not subjected to the natural limiting factors present in their “home” ecosystems. These outsiders don’t play by the   Invasive Old World new ecosystem’s ‘rules’ and climbing fern enshrouds can disrupt the delicate cypress trees in Florida as entomologist Robert ecological balance. Native Pemberton surveys salt marsh cordgrass of the the scene. The weed’s southeastern U.S. coastal leafy skirts can funnel zone, for example, provides wildfire flames to the tops of trees that might important habitat along the otherwise survive a blaze. eastern Atlantic Flyway, but Credit: Peggy Greb/USDA is considered highly invasive © The Wildlife Society

in Pacific Northwestern coastal mudflats, which must remain weed-free for migrating shorebirds of the Pacific Flyway. The impacts of invaders aren’t always immediate. Exotics may lie quietly for years, even decades, seemingly invisible or without effect until, for whatever reason, these sleeper cells reach a threshold. In almost all such cases they blitz native species so quickly that there is no ability for natives to adapt, repel, or survive the threat. The same stunned surprise may befall resource managers when they wake up to find their guarded habitats being overrun, or their cherished wildlife populations dying by the thousands. Over the past century, our professional track record for meeting the challenge of invasive species has left much to be desired. Too often we wave the white flag of surrender. But the cost of such surrender is too high. An inadequate response against the invasive species threat could render a century of conservation laws, policy, and management actions irrelevant. As we struggle to plug the holes in our respective local, state, provincial, and national economic buckets and hold the ground we have gained for conservation in North America, it is critical for wildlife professionals and others in society to join together and provide science-based, long-term solutions to address the threat of aquatic and terrestrial invasive species. Now is not the time for wildlife professionals to play a marginal role. We need to move out in front of the invasive species issue and lead those who would rather follow. If not, just imagine: All the past political and financial battles you have fought to protect and restore native plants, animals, and habitats could be lost in a few seasons. Unimaginable.

Credit: Sofia Ielmini

Michael Ielmini, CWB, is the National Invasive Species Program Manager for the U.S. Forest Service.


A Call to Action The Scope of Invasive Impacts Demands Response By Michael Ielmini, Gail Wallin, and George Beck

W Credit: Sofia Ielmini

Michael Ielmini, CWB, is the National Invasive Species Program Manager for the U.S. Forest Service.

hen crude oil is washing up on our beaches, or a hurricane bears down on our community, or a wildfire is raging toward our homes, we act quickly and decisively to prevent or mitigate damage. So why do individuals, communities, and governments often stand idle against the onslaught of invasive species? Nonnative animals, plants, and pathogens that become harmful (invasive) in ecosystems are threatening to wipe out a century of conservation gains in North America, irreparably transforming our landscapes and costing our economies billions of dollars. The threat is at least as massive, fast-moving, and tangible as the global climate change crisis, with impacts mounting daily at every level. This is the age of the “homogocene,” a term coined by ecologist Gordon Orians to describe the current period of global history in which widespread and rapid mixing of species is occurring at rates never before known on the planet (Rosenzweig 2001). Research shows that about 42 percent of threatened or endangered species are at risk primarily because of invasive species (Wilcove et al. 1998), and we

Credit: Daniel Herms/The Ohio State University

humans have made their rapid spread possible through high-speed transportation and trade, deliberately or inadvertently moving species to new areas of the world literally overnight. The influx, combined with shifting climates and inaction, creates potential for the perfect storm of invasive species impacts across the planet. Scientists and conservationists are aware of the issues. Now, awareness must yield to action.

Laying the Foundation

Warnings and calls to action against the spread of invasive species are not new. For decades, wildlife and fisheries professionals, ranchers, farmers, foresters, and others have recognized that invasive species pose a major environmental and economic threat demanding management and policy action. Concerns about invasive species accelerated in the latter part of the 20th century, resulting in several broad-based efforts to help lay the foundation for a coordinated response. In the early 1990s, for example, the Aquatic Nuisance Species Task Force (ANSTF) and the Federal

Credit: Daniel Herms/The Ohio State University

Once lush with leaves that shaded a street in Toledo, Ohio, in 2006 (left), ash trees along the same street stood denuded and dying by 2009 (right), victims of the invasive emerald ash borer (Agrilus planipennis; see adult on facing page). In a nearby forest, ash tree death rates rose from 30 percent to 99 percent from 2005 to 2008 as ash borer populations climbed. Such massive tree die-offs can create forest gaps, which encourage the further spread of exotic species.


The Wildlife Professional, Summer 2012

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Interagency Committee for the Management of Noxious and Exotic Weeds (FICMNEW) were established in the U.S. to help provide a coordinated structure to identify problems, recommend policy and management practices, foster partnerships with state and local governments and the private sector, and identify needs for research, technology, and public education about harmful exotic species. In 1992, Canada was the first industrialized country to ratify the United Nations Convention on Biological Diversity, developed at the multinational Rio Earth Summit earlier that year. The convention called on all parties to prevent the introduction of invasive species and to “control or eradicate those alien species which threaten ecosystems, habitats, or species.” Soon after, the U.S. Office of Technology Assessment (OTA) published a landmark report titled “Harmful Non-Indigenous Species in the United States” (OTA 1993)—at that time the most comprehensive review of the invasive species issue ever undertaken by the U.S. government. The OTA report left no doubt regarding the magnitude of the threat and the need for enlightened policies, reliable information, and adequate resources to effectively safeguard “our national interests.” A few years later, in 1996, 80 nations met in Norway for the UN Conference on Alien Species, the first major international conference on the invasive species issue, highlighting the implications to conservation, sustainable development, and world trade. After FICMNEW released “Pulling Together—A National Strategy for Invasive Plant Management” in 1997—supported by more than 100 conservation organizations—roughly 500 scientists and conservationists (including such notables as E.O. Wilson, Don Schmitz, and Peter Vitousek) sent a letter to Vice President Al Gore with a compelling request to increase the nation’s response to the global invasive species problem. Gore directed the departments of Agriculture, Commerce, and the Interior to plan a coordinated attack on the problem. In 1999, that effort was formalized when President Clinton signed Executive Order 13112, establishing the National Invasive Species Council (NISC) and outlining U.S. federal agency responsibilities to address the invasive species problem. Recent years have seen additional infrastructure advancements against invasives. States have been

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actively creating invasive species councils and passing relevant legislation and, in 2003, the U.S. established the National Environmental Coalition on Invasive Species (NECIS), a coalition of environmental groups—now including The Wildlife Society—that provides scientific expertise to influence invasive species policy. Likewise, in 2004 Canada released “An Invasive Alien Species Strategy for Canada” calling for a coordinated national response. Today, Canada has a National Invasive Species Council in place and almost every prov-

Aptly named for its green gleam, the emerald ash borer is projected to kill most of the nearly eight billion ash trees (Fraxinus spp.) throughout North America, causing damage at a scale greater than that from chestnut blight or Dutch elm disease. Credit: Daniel Herms/The Ohio State University

ince has a non-profit council involved in the effort. More recently, in early 2011, NECIS sent Congress and President Obama An Action Plan on Invasive Species requesting adequate funding for specific actions to combat invasives, such as tougher regulations and screening of non-native plant and animal imports.

Moving from Talk to Action

All the coalitions, agencies, conferences, and action plans in the world can’t solve the invasive species problem if we don’t take meaningful action. Ultimately, effective action against invasives will require changing human behavior across the broad spectrum of our society, a major challenge in itself. Intentional human actions—such as importing exotic pets and plants, moving bug-infested firewood from one forest to another, or dumping bilge water filled with invasive mussels—must be curbed. Such human-accelerated biological invasions are a widespread and significant component of anthropogenic global environmental change, and represent a breakdown of the regional distinctiveness of Earth’s flora and fauna, thereby

Co-author Affiliations Gail Wallin is Executive Director of the Invasive Species Council of British Columbia. George Beck, Ph.D., is Professor of Weed Science at Colorado State University.


Laurel Wilt Fungus Not Just a Threat to Avocados The Asian redbay ambrosia beetle (Xyleborus glabratus) is half the length of an eyelash and resembles an armor-plated, flying coffee bean (right). It bores into the trunks of trees, leaving telltale strips of frass (below), and begins to cultivate fungal spores that females transport inside their head. The fungus provides food for the beetle but also cuts off the tree’s food and water transport system, killing a healthy tree within months. This disease, called “laurel wilt,” attacks at least eight Laurel family species, including avocado. Likely arriving in a shipment from abroad, the beetle was first detected in 2002 in a survey trap near a Savannah, Georgia port. This year, the Florida Department of Agriculture and Consumer Services and the University of Florida Institute of Food and Agriculture Sciences announced that laurel wilt had reached a commercial avocado orchard in Florida. Though the crops have not yet suffered, the fungus kills more than 92 percent of related host species in infested areas. Replacement of the state’s avocado trees could cost more than $400 million (Evans 2009)—not to mention the costs of pest management, lost jobs and avocado sales, and reduced property values.

Credit: Michael C. Thomas/Florida Department of Agriculture and Consumer Services

Credit: Bud Mayfield/U.S. Forest Service Environmental costs are more difficult to quantify. Before the disease reached the Florida avocado orchard, it raced through Georgia, North and South Carolina, Mississippi, and other parts of Florida, devastating native redbay tree populations. It also kills native sassafrass, and has been found in dying pondspice and pondberry trees, which are federal and state endangered species, respectively (U.S. Forest Service 2011). “If this invader had been addressed when it first started killing trees near Savannah, the Florida avocado industry wouldn’t be at such high risk now,” says Michael Ielmini, National Invasive Species Program Manager for the U.S. Forest Service. No effective fungicidal treatment for laurel wilt in avocado exists, and several insecticides are still under development. The best strategy is to destroy infected trees and prevent the transport of beetle-infested wood. “Too bad we don’t make guacamole out of redbay fruit,” Ielmini says.

—By Jessica P. Johnson

degrading human health and threatening native biodiversity (Vitousek et al. 1997). By adapting programs that have successfully changed human behaviors in the past—such as those regarding seat-belt safety, smoking, littering, and recycling—we can encourage the public to adopt “social norms” that decry the introduction of invasives and support their removal.


The Wildlife Professional, Summer 2012

A few such efforts are already underway. For example, a U.S.-based group called Protect Your Waters offers the “Stop Aquatic Hitchhikers” program to teach recreational boaters how to prevent the spread of non-native plants, animals, and organisms that may be transported on boating equipment. Canada’s Clean, Drain, Dry program offers similar education and outreach. The Don’t Move Firewood campaign teaches campers about tree-destroying pests and how to avoid transporting them in bundles of firewood. Wildlife Forever’s Threat Campaign teaches hunters, anglers, boaters, and others about the need to combat the spread of invasives. And Australia and Canada offer the Grow Me Instead campaign to teach gardeners about which plant species are non-native for their particular regions. Success against the grasp of an invader is usually achieved at relatively small scales, at a community or watershed level. But persistence is necessary, and those small victories are vital: Once established, an infestation creates exponentially increasing losses and management costs. Being proactive is therefore critical, but the concept of “pay now, or pay a lot more later” seems to be hard for some to accept. When we procrastinate, the rates of invasive species establishment and spread almost always outpace control and containment efforts. Those efforts, however, may be stymied by debates over the methods of control (such as applying pesticides or using biological controls), particularly regarding short-term risks of collateral damage to native species. Repelling an entrenched invasive ‘enemy’ may result in the killing of some ‘civilian’ natives. Conservation professionals need to understand that the invasive species battle will be hard, bloody, and unpleasant, and they should be willing to use whatever integrated tools are necessary to achieve the desired conditions on the landscape. Sometimes, a few of the innocent will be harmed for the sake of the long-term protection of the broader ecosystem. Those in our society who want a guarantee that there will be no casualties to individual non-target native species probably don’t fully understand that invasive species pose a much greater danger to the long-term survival of those native species.

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The Cost-Benefit Equation

Deciding what action to take may be easier than deciding how much to take—or to spend. “Every delay adds costs and lowers our chances of success,” says the National Wildlife Federation’s Corry Westbrook as quoted in the NECIS action plan. Calculating what is cost effective is itself a massive challenge, however, because although the price for any management action can be high, the cost for inaction may be far worse. Consider: • The Nature Conservancy estimates that damage from invasive species worldwide in 2010 totaled more than $1.4 trillion—5 percent of the global economy (TNC 2011). • Researchers from Cornell University have estimated that the economic impact from invasive species in the U.S. exceeds $120 billion annually (Pimentel et al. 2005). Such damages include en-


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vironmental impacts (loss of ecosystem services) as well as economic losses in property values, tourism, and infrastructure. • Preliminary research on the Great Lakes region suggests that the annual cost from invasive species introduced by shipping may exceed $200 million a year, in part because invasions limit the ability of the natural ecosystem to support fisheries, raw-water uses, and wildlife watching (Lodge and Finnoff 2008). • A study of invasive weeds on public lands in Nevada estimated lost wildlife-related recreation values from $5 million to $17 million per year, with as much as $34 million lost over a five-year period (Eiswerth et al. 2010). No matter how we measure the impacts, dealing effectively with invasive species is economically

Snakehead Fish The Stuff of Horror Films Some call it Frankenfish. Others, Fishzilla. With a snake-like head and sharp teeth for impaling prey, the invasive snakehead fish (Channa spp.) is a voracious predator that eats whatever crosses its path—especially other fish, even its own species. It can also out-compete native species in poor habitats because it survives on low oxygen, enabling it to live under ice or mud for months. It can even breathe air and survive on land as long as it stays moist—a trait that has inspired a string of B movies about killer fish walking the Earth. In 2000, the first breeding population of snakehead (C. argus, below) was discovered on the U.S. mainland in Florida, and just two years later it appeared in Maryland. Native to Asia, the snakehead has been available through the pet trade since at least 1912 (Courtenay and Williams 2004), but sightings in the wild increased only recently. The snakehead has most likely spread through intentional release by humans (FWS 2003) to create wild breeding populations that can support increasing demand for the fish, a delicacy in Asian cuisine. “Snakehead fish have a high potential for being invasive,” says Joseph Love, a tidal bass specialist with the Maryland Department of Natural Resources (MDNR). Today, the fish is known to be breeding throughout the Potomac River watershed and in parts of Arkansas, New York, Delaware, New Jersey, and Pennsylvania. It has also been sighted in Massachusetts, Illinois, California, and North Carolina. The MDNR is now focusing on curbing the snakehead’s spread rather than complete eradication. In 2002, trade in four species of invasive snakehead fish (C. argus, C. marulius, C. micropeltes, C. maculata) was banned under the injurious wildlife provision of the federal Lacey Act, and it is now illegal to possess the fish in 23 states. But the snakehead has few barriers to establishment in the wild, so there’s a high probability that it will continue to spread (USGS 2004). “We’re concerned about it,” Love says. “Not only are they a tolerant beastie, but they’re also one that’s good at colonizing new habitats.” For North America’s native fish, that’s the real horror story. —By Jessica P. Johnson

Credit: Joshua Newhard/USFWS

© The Wildlife Society


Phragmites (Common Reed) Success Through Collaboration Since at least the 1960s, a European species of common reed (Phragmites australis) has hidden, seemingly benign, among native reed species in Nebraska’s Platte River Basin. But a drought in the early 2000s left many channels dry, and the exotic species began to thrive (above left) before channels were cleared (below) by herbicides. “We were kind of asleep on this one,” says Rich Walters, coordinator of Nebraska’s Platte Valley Weed Management Area (PVWMA) and Implementation and Evaluation Coordinator for The Nature Conservancy. “In six years we went from barely noticing it to it dominating the channels.” The plant spreads as quickly as five feet per year and grows up to 19 feet tall, forming dense stands that crowd native plants, repel wildlife, and clog river flow. After Phragmites was removed from the nearby Republican River, its flow rate increased 400 percent, according to Mitch Coffin, manager of the Nebraska Department of Agriculture’s (NDA) Animal and Plant Health Protection Noxious Weed Program.

Credit: Rich Walters/The Nature Conservancy

In 2008, armed with NDA funding, Walters led a multi-agency effort to reclaim 336 miles of the Platte River. He built partnerships and coordinated Phragmites removal by some 700 landowners plus state and federal weed management and natural resource agencies. Between 2008 and 2011, they used helicopters to locate and spray nearly 19,000 acres of monotypic Phragmites stands with Imazapyr, an herbicide deemed safe for aquatic habitats. The spraying is so precise that “we can kill a Phragmites stand and not affect a willow a foot away,” Walters says. Some 90 percent of the $2.5 million project budget has been spent on herbicide application and removal of dead Phragmites stems. Now the effort is transitioning into long-term monitoring and maintenance, with landowners playing a key role. Walters considers Phragmites on the Platte River to be under control, though he believes it will never be eradicated. Before treatment, the only wildlife he saw using Phragmites stands were white-tailed deer in search of a hiding place. “The birds wouldn’t even nest in it,” he says. Because the Platte is a major migratory staging area for the Central Flyway, that was a big concern. But now, Walters has seen wildlife return to treated areas, and native annual plants growing on sandbars and riverbanks. “It’s a good story because we got on top of it,” he says. “But it’s a sad story because we let it get that bad.”

Credit: Rich Walters/The Nature Conservancy

vital. Management treatments need to surpass an invader’s ability to spread, but with limited budgets, resource managers must evaluate the economic and environmental costs of doing a little (and perhaps wasting money) versus doing enough to make a difference. That calculation often leads to sticker shock. For example, a report by the Maine Department of Environmental Protection (MDEP) notes that all New England states as well as 41 other states and six Canadian provinces are battling Eurasian watermilfoil, water chestnut, zebra mussels, and other waterborne invasives at a cost ranging from $200 to $2,000 per lake acre per year—with no end in sight. Vermont alone spends more than $200,000 annually


The Wildlife Professional, Summer 2012

—By Jessica P. Johnson

just on the staff who manage invasives at 46 of the state’s 285 larger lakes. In their book Fading Forests II: Trading Away North America’s Natural Heritage, authors Faith Campbell and Scott Schlarbaum note that “public agencies have already spent tens of millions of dollars attempting to eradicate just one of several recently introduced pests—the Asian long-horned beetle.” But if that beetle thwarts containment efforts, they write, “it will cost an estimated $600 billion to replace city trees killed” by the bug, along with additional losses from declines in tourism, maple syrup sales, and timber production (Campbell and Schlarbaum 2002).

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Clearly invasive species are draining our economy on many levels. The solution, then, may lie in simultaneously addressing both the economic and environmental problem by using the fight against invasives to stimulate new jobs, not just in eradication and control but in research, technology, education, marketing, and other fields. President Obama recently took a step in that direction when, in February 2012, he announced a new Veterans Job Corps program that would include $1 billion in conservation funds, some of which would go toward employing veterans to eradicate invasive species.

Getting off the Dime

Such programs may help plug the holes in our economic buckets, but they aren’t enough, and the broader conservation community—particularly the fish and wildlife management profession—appears to be significantly overwhelmed by the scale and complexity of the invasive species problem. Declining government capacity to fund conservation programs also limits our ability for proactive action. Like many other conservation issues, there are too few resources and too many priorities to address, particularly on public lands. Private landowners (who control the majority of the landscape) are in even worse shape, having little capacity to protect themselves or their neighbors against harmful aquatic or terrestrial invasions. In addition to the significant lack of investments, our conservation profession seems to be devolving into bureaucracy, with our traditional “get-erdone” genes transitioning to a recessive trait. With relatively porous borders and the global expansion of trade and transportation, thousands of invasive species are storming the gates while we fumble about with more bureaucracy and search for silverbullet solutions that are politically neutral and often hamper the immediate response needed to repel the onslaught. When environmental contaminants poison our children, society is usually quick to call for stronger regulatory protections for the environment and human health. When our economic stability is under assault, we respond with massive amounts of money and policy revisions to patch the holes. Likewise, success against invasive species may be found by showing that this is as much a human-health and economic issue as an environmental one, thereby broadening the set of supportive stakeholders.

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Credit: Billy Higginbotham/Texas AgriLife Extension Service/

Feral pigs root over a patch of Texas land. Having up to four litters per year, non-native feral pigs spread fast. They have reached at least 37 U.S. states and cost the country some $1.5 billion a year in damages. Hoping to prevent the spread of Asian long-horned beetles, Canadian authorities posted a sign in Toronto warning about the risks of transporting firewood. Credit: GTD Aquitaine/Wikimedia

The agriculture, fisheries, forestry, ecology, and wildlife management professions need to reinvigorate their collective energies against aquatic and terrestrial invasive species and take a leadership position on this issue—or risk losing the ground we have gained for conservation. We must join with the public and private sectors to address the clear and present danger of invasive species. The call to action is now! The solution is working together to stop the spread. This article has been reviewed by subject-matter experts.

For additional resources about the scope and impacts of invasive species (including yellow starthistle), go to


Tackling an Invasion Wildlife professionals grapple with invasive species By Divya Abhat


rizona has an American bullfrog (Lithobates catesbeiana) problem. These voracious predators—native to the central and eastern U.S. but not to the West—have been chomping their way through the state, preying on almost anything, including turtles, snakes, and other frogs. So, in the early 1990s, when biologists learned that a population of now federally threatened Chiricahua leopard frogs (Lithobates chiricahuensis) existed on Arizona’s Buenos Aires National Wildlife Refuge— also home to thousands of invasive bullfrogs—it was time to sound the alarm.

Divya Abhat is the Managing Editor of The Wildlife Professional.

The U.S. Geological Survey, the U.S. Fish and Wildlife Service, and the University of Arizona joined forces and began to survey the refuge for bullfrogs. Once you know where the bullfrogs are, you can plan a systematic attack to get rid of them, says USGS ecologist Cecil Schwalbe, who was involved in the effort. Using funds from the Amphibian Research and Monitoring Initiative (ARMI), a federal program created to determine the status and distribution of amphibians on federal lands, Schwalbe and colleagues launched an unforgiving attack.

They captured bullfrogs by hand and also fenced off bullfrog-infested ponds and pumped them dry. After they had captured most of the bullfrogs, they mopped up the rest by shooting them at night, using 22-caliber rifles with telescopic sights. Because bullfrogs can move as far as seven miles in less than a week (Suhre 2009), it was especially critical to get to the very last one. Over the next decade, biologists used ARMI funding to monitor the region for bullfrogs, making sure they steered clear of all leopard frog sites. “As of now, bullfrogs no longer occur near leopard frog sites on Buenos Aires National Wildlife Refuge,” Schwalbe says. “It’s the first good news we’ve had on bullfrog control in the last 20 years.” Such good-news stories are relatively rare. Invasive species haven’t spared a single ecosystem across North America. In Hawaii alone, more than 4,500 invasive plants and animals have become established in the wild. Local, state, and federal agencies and organizations are doing their best to address this growing problem. Several legislative policies are in place (see page 70), such as the National Invasive Species Act, which helps prevent the spread of invasive species in U.S. waters, and the Lacey Act, which monitors import of injurious species. In February 1999, President Bill Clinton issued an Executive Order that called for the creation of the National Invasive Species Council to ensure that federal programs and projects to manage invasive species are coordinated and efficient. The order tasked the council with creating an Invasive Species Management Plan that would serve as a blueprint for all federal action on invasive species. The most recent plan, released in August 2008 and valid through the end of this year, highlights the need for management defenses, such as prevention (the first line of defense), early detection and rapid response, control, restoration, and collaboration (National Invasive Species Management Plan 2008).

Credit: South Florida Water Management District

Jim Creber (left) and Wade Harper of Applied Aquatic Management, Inc., got a surprise while treating Old World climbing fern at a Water Conservation Area in Miami: They found and removed an engorged Burmese python with an adult white-tailed deer in its belly.


The Wildlife Professional, Summer 2012

Controlling the Invaders

Most species aren’t regulated or controlled federally, so states have passed a number of laws to address the problem at a local, state, or regional © The Wildlife Society

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level. In 2002, the Environmental Law Institute released an extensive report that, among several other issues, explored how states can approach invasive species policy by enforcing permits to own certain potentially invasive species and enhancing invasive monitoring systems. Although it’s no easy feat, wildlife professionals are tackling the issue head-on through policy and hands-on management. Consider the Nile monitor lizard (Varanus niloticus). This aggressive, intelligent, hefty reptile species came to the U.S. from Africa as part of the exotic pet trade and was likely released into the wild. First observed in Florida’s Cape Coral area in the 1990s, these reptiles are now all over the state, feasting on a diverse diet of fish, alligators, snakes, and turtles, with an affinity for egg-filled nests and newborn young. After several attempts to eradicate these destructive invasives, researchers may have finally found just the thing to choke their growth: Acetaminophen (Mauldin and Savarie 2010). Researchers with the U.S. Department of Agriculture’s (USDA) National Wildlife Research Center inserted acetaminophen tablets deep into the esophagus of dead baby mice and fed them to the lizards. The results were successful: A 40-mg dose of acetaminophen guaranteed a lizard’s death, while a smaller dose of 20 mg resulted in 50 percent mortality. Elsewhere in the South, Gary Witmer and colleagues at the National Wildlife Research Center are exploring methods to control Louisiana’s 20 million nutria (Myocastor coypus)—extremely prolific invasive rodents that have damaged hundreds of thousands of acres of wetlands, especially in Louisiana and Maryland (Witmer 2008). In a field trial, researchers placed 25 cage traps on the marshes of Louisiana’s Mandalay Wildlife Refuge. Each trap had a one-way door, so a nutria could enter the trap by itself, but couldn’t leave. In an effort to understand the effectiveness of certain foods in luring nutria, researchers lined the traps with treats like fertilized marsh plants, corn, and chopped carrots. “They worked very effectively,” Witmer says. In a later study, Witmer analyzed the effects of semiochemicals (chemicals such as urine released by animals to attract other animals of the same species) and found that the chemicals increased trapping success by two to 2.5 times (Jojola 2009). Although these methods haven’t been adopted at the state level, researchers in the Pacific Northwest are exploring similar studies with hopes of implementing them in the region. © The Wildlife Society

Captured and sedated in Oregon, a nutria receives a health exam before being tagged and released. By tagging and recapturing these invasive rodents, biologists can estimate populations and determine how fast and far they spread. Credit: Tess McBride/USFWS

When it comes to dealing with rogue nutria, Maryland is a close second to Louisiana. “We have a much smaller population, but the damage is significant,” says Steve Kendrot, biologist with the USDA’s Wildlife Services in Maryland. In 2002, Wildlife Services launched an integrated eradication campaign with FWS, the Maryland Department of Natural Resources, and private landowners throughout the region with the goal of eradicating the species from the Delmarva Peninsula. “To date we’ve trapped about 13,000 nutria from 150,000 acres of coastal marsh, spread across five counties in Maryland’s lower eastern shore,” Kendrot says. USDA researchers are also exploring new approaches to manage the species. A few years ago, they used “Judas” nutria— animals that have been surgically sterilized, outfitted with tracking devices, and released—to find residual populations by following the sterilized nutria back to their pack. Kendrot believes Maryland is in the homestretch for eradication. “We think that with another four to five years of hard work, we can claim to have caught the last nutria on Delmarva.” Maryland is also plagued with a far lovelier invader: mute swans (Cygnus olor), which can destroy aquatic plant beds and compete for habitat with native wildlife. The initial public perception of mute-swan management, however, can be very different from the


perception of rodent control. The beautiful white birds have a small but emotional fan following, especially in the animal-rights community, which has complicated the state’s control efforts to an extent. Still, Maryland biologists have removed 95 percent of the state’s mute swans by lethal control, and are working to further reduce their numbers as much as possible.

Credit: Stephen Ausmus/USDA

Contractors for land management agencies spray herbicides to control invasive melaleuca trees in the Everglades. If left alone, the melaleuca visible in the foreground would take over the sawgrass area in the background, which is more representative of the natural state of the Everglades before a melaleuca invasion.

As part of a U.S Forest Service video on preventing invasive species, an angler scrubs his waders with a cleaning solution and water to wash off any invasive species, including New Zealand mud snails, that might have latched on while he was fishing in Colorado’s Upper Arkansas River Basin.

The California Department of Fish and Game (CDFG) also dealt with a fair share of public opposition over its efforts to kill a population of invasive northern pike in Lake Davis. Biologists planned to kill the fish by applying rotenone, a plant-based chemical. But because the lake also served as a backup source of water supply for California’s Portola City, residents were concerned about health impacts. “For years … we worked closely with the Lake Davis Steering Committee,” says Katherine Hill, environmental program manager with the CDFG. “We wanted to bring the public along every step of the way.” The department tried detonation, gillnetting, electroshocking, and eventually applying rotenone—with apparent success. For now, Lake Davis appears to be free of northern pike. Control and eradication efforts come with other challenges besides public perception. Most biologists know that even if invasive species numbers have been slashed, it’s nearly impossible to get the final few without long-term vigilance. There may also be risk that invasive species treatments will impact non-target native plants or animals. “Willingness (or unwillingness) to accept short-term losses and collateral damage to achieve long-term restoration success across the landscape is a major factor that separates success and failure,” says Michael Ielmini, National Invasive Species Program Manager with the U.S. Forest Service. “Using integrated pest management approaches, resource managers should set thresholds and assess the potential risks to non-target native species before implementing treatments.” When invasive weeds are intermingled with native species, there may be options to use selective herbicides to reduce the risk to non-target native plants, or to time herbicide applications so they are offset from critical growth and developmental periods of native plants or animals. According to George Beck, weed science professor at Colorado State University, there is growing evidence to show that impacts to non-target native plant populations in the treatment area may not be

Credit: Bob Nichols/USDA


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nearly as significant as was once thought. “University research is finding that herbicide treatment effects on native plant populations are largely transient and usually disappear after two to three years, and few, if any, native species in the application area are completely eliminated,” Beck says. For biologists, all that is usually necessary to restore most of these sites is to remove the competing invaders and allow the native species to regain their dominance.

When Prevention is Better than Cure Generally, invasive species management is more reactive than proactive. “If you look at the USDA or even a multi-agency budget that’s trying to address these species, most of the funding goes directly toward response to address ongoing invasions,” says Read Porter, who directs the Environmental Law Institute’s (ELI) Invasive Species Program. “A little more investment in identifying and proactively preventing [invasive species] could save us a lot.” To remedy that, ELI, The Wildlife Society, the National Wildlife Federation, and other organizations—all part of the National Environmental Coalition on Invasive Species (NECIS), which works on invasive species policy—have been identifying the costs and benefits of a more proactive approach to managing invasive species.

For example, risk assessment studies that identify the potential threat of a particular species can cost a lot less than subsequent eradication efforts. A recent study on the value of risk assessments of non-native animals in international trade estimated that the long-term net benefits from risk screenings can range from approximately $54,000 to $141,000 per assessed species (Springborn et al. 2011). The study helps inform an ongoing debate in the U.S. over whether federal agencies should require a risk assessment before allowing import of a species. Once a species has been identified as potentially risky, a speedy response (by way of eliminating it from the region or imposing strict regulations) also helps keep invasive species in check. “There’s no real [national] system set up that allows a quick response when a species does invade and looks like it’s going to be a

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How to Become an Invasive Species Manager By Madeleine Thomas

There is no official federal job titled “Invasive Species Manager,” yet the need for expertise in spotting, containing, and removing invasives is steadily on the rise. In such a young industry, how do you learn the ropes? According to Steven Manning, president of Invasive Plant Control, Inc. (IPC), a private firm in Tennessee, those interested in a career in invasive species management need to “get out in the field” to gain first-hand experience battling alien species. Opportunities include volunteering with habitat restoration crews or joining state task forces and councils working on invasive species control. Aside from field work, says Manning, “it’s a matter of training and education.” All of Manning’s permanent staff members must have an undergraduate degree in a natural resource management-related field, mainly so they can differentiate between native and non-native plant species and understand the effects of seasonal and regional management techniques. If a university or agency doesn’t offer such courses, there are other options. For example, Randy Westbrooks—a longtime veteran of invasive species management with USDA-APHIS and the USGS, and now an Associate with IPC—has developed an online Invasive Species Management Training Program for those seeking to learn the basics. His six-course program covers prevention and exclusion (federal/state regulatory programs), early detection and rapid response (reporting, assessment, and eradication), and general control methods—a “foundation,” he says, “that would otherwise take 15 years in the field to learn.” Open to all, the online course is available through the Environmental Science Technology Program at Southeastern Community College in Whiteville, North Carolina. It is generally offered at one course per semester to fit the schedule of working professionals.

Credit: Bob Nichols/USDA

Volunteers with the Sonoran Desert Weedwackers dig invasive buffelgrass in the Saguaro National Park near Tucson, Arizona, as part of a U.S. Forest Service video, “Playing Smart against Invasive Species.”

Shauna Lehmann, an environmental engineer with the provincial government of Saskatchewan’s Ministry of Highways and Infrastructure, is a student in Westbrooks’ program. She found herself challenged when tasked with developing legislative policy and practices for weed management along Saskatchewan highways, so she enrolled in the course to learn about invasive weed impacts, regulations, and management options. “I really needed to familiarize myself with a new provincial weed control act,” Lehmann says. “I could read [it,] but not knowing the background … made it difficult.”

Westbrooks says that many of his students enroll in his courses because, like Lehmann, they enter the workforce without any prior background in invasive species management, only to face a related task down the line. “I think that’s one of the reasons we’ve been so supportive of Randy’s program,” says Steven Manning. “We need to fill these jobs with people that have that training. … Having these courses will allow people just coming out of college and those that have been in the industry for 30 years to gain those skills.” Madeleine Thomas is the Editorial Intern for The Wildlife Professional.


problem,” Porter says. According to a Defenders of Wildlife report, it can typically take the government four years to prohibit one non-native species under the Lacey Act (Defenders of Wildlife 2007).

See previous issues of The Wildlife Professional for in-depth coverage of non-native feral horses (winter 2010), feral cats (spring 2011), and feral swine (summer 2011).

Monitoring for invasive species is critical, too. Most states have inspection stations set up to check boats coming in from other states and keep a potentially destructive species from making its way into the state in the first place. In Oregon, Rick Boatner, biologist with the Oregon Department of Fish and Wildlife, oversees the state’s invasive species program and manages its four stations set up to check boats for invasive zebra and quagga mussels, weeds, New Zealand mud snails, and other invasives. A few years ago, the department introduced a trailermounted pressure washer that shoots 140-degree water at 3,000 pounds per square inch out of a 225 gallon tank onto boats with weeds and other invasive critters. The idea is to blow them right off so there’s no risk of them making it into state waters. States are also closely monitoring the pet trade, which can be a source of illegal invasive introduc-

tions. Often people will buy a reptile as a pet, not knowing whether it’s native to the state or not, and later release the unwanted pet into the wild. “It’s a difficult side of enforcement,” Boatner says. “A lot of it you can get off the Internet and … it’s hard to monitor.” According to Boatner, it’s easier to monitor things coming from outside the U.S. because they have to go through a port of entry. Educating the public and raising awareness about invasive species is clearly an important strategy in the war on invasives. In some cases, that requires educating the educators. Crayfish, for example, are often used in middle-school curricula so students can learn about their physiology and biology. “They’re an easy animal for the classroom,” Boatner says. But instead of euthanizing them when they’re done with their study, classes will often release them into the nearest water body. “We know for sure that the rusty crayfish was introduced into Oregon that way,” Boatner says. It’s what he refers to as the Free Willy Syndrome. “They must be released to be free because that makes them happy.”

Future of Invasives Management

Awareness of the problem does appear to be growing. Most states have an online reporting system that allows citizens to notify agencies if they spot a suspicious-looking creature. Some states also support smart phone apps with the same purpose. The “What’s Invasive!” app, which started in California but has since expanded, displays lists of local invasive weeds and pests along with their images and descriptions, while the “California Observer” app describes more than 10,000 California plants. Similarly, Early Detection and Distribution Mapping System, or EDDMapS, developed by the University of Georgia’s Center for Invasive Species and Ecosystem Health, has both weband mobile-based mapping tools to track and report invasive species across the U.S. Every day, invasive species jump, crawl, swim, fly, or otherwise latch themselves onto a new habitat. Researchers and wildlife managers are trying to rein in the problem by introducing new technologies, adaptive management measures, and innovative policies. The ultimate key, however, is information. “Know thy enemy,” says the USGS’ Cecil Schwalbe. “The more you know about the enemy, the more likely you are to be able to combat it.” This article has been reviewed by subject-matter experts.


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Freeing Islands from Rodents Broadcast Rodenticides Help Native Species Recover By William Pitt, Daniel Vice, Dana Lujan, Diane Vice, and Gary Witmer

To protect natural resources from rodents, biologists and landowners have typically applied anticoagulant rodenticides through bait stations. Though such stations can effectively eradicate rodents in small areas, they have not been feasible or effective in larger areas or on inaccessible islands. In 2005, USDA-APHIS Wildlife Services, in collaboration with the U.S. Fish and Wildlife Service (FWS) and two private companies, achieved a breakthrough in large-scale rodent eradication by developing and registering three new anticoagulant rodenticide products for broadcast application, either by hand or by air. To date, these products— Diphacinone 50 Conservation, Brodifacoum 25W Conservation, and Brodifacoum 25D Conservation— have helped successfully eradicate rodents from numerous islands in California, Florida, Alaska, Hawaii, and through the Virgin Islands, American Samoa, and the Pribilof Islands. Once the rodents were gone, the recovery and restoration of wildlife on these islands has been dramatic.

minutus) and Micronesian starlings (Aplonis opaca). Rats were also limiting the ability of wildlife managers to detect and eliminate a potential population of brown tree snakes (Boiga irregularis) on the island. The reason: When there is an ample supply of rodent prey in the environment, foodbased control tools are less effective against snakes. It was believed that if brown tree snakes became established on Cocos, this would ultimately lead to the loss of all nesting birds on the island. Rodent eradication and prevention of snake establishment on Cocos were especially critical because, in 2006, the Guam Department of Agriculture’s Division of Aquatic and Wildlife Resources initiated the Ko'ko' for Cocos Project, an ecosystem restoration effort aimed at establishing a breeding population of endemic Guam rails (Gallirallus owstoni)—locally known as the ko'ko'—on Cocos Island. The project included the release of captive-bred Guam rails, which are federally listed as endangered and are extinct in the wild on Guam. Partners in the rodent eradication included the Cocos Island Resort, USDA-APHIS Wildlife Services, FWS, and the U.S. Department of the Interior’s Office of Insular Affairs.

Credit: Avra Miller

William Pitt is the Field Station Leader and Project Leader with USDA-APHIS Wildlife Services’ National Wildlife Research Center Hawaii Field Station in Hilo, Hawaii.

Courtesy of Dana Lujan/USDA-APHIS-WS


nvasive rodent species occupy more than 80 percent of island groups worldwide, with devastating impacts to native flora and fauna. Rodents prey on birds, mammals, reptiles, amphibians, and invertebrates, and indirectly affect native wildlife by destroying plants, competing for food, and transmitting disease. Species such as Norway rats (Rattus norvegicus), black rats (R. rattus), and Polynesian rats (R. exulans) have caused the extinction of several species of native birds, mammals, and lizards (Atkinson 1985). For example, less than a decade after black rats were accidentally introduced to Big South Cape Island in New Zealand in the early 1960s, one bat species— the greater short-tailed bat (Mystacina robusta)—and five bird species, including the South Island snipe (Coenocorypha iredalei), went extinct (Bell 1978).

Victory on Cocos Island

One of the most-notable recent success stories in rodent eradication has occurred on tiny Cocos Island, a 34-hectare island immediately south of Guam. There, superabundant invasive Polynesian rats had been impacting native birds and other island species, including nesting black noddies (Anous © The Wildlife Society

Credit: Daniel Vice/USDA-APHIS-WS

Polynesian rats clog a brown tree snake trap on Cocos Island, Guam. Though the rats were abundant and the snakes were rare on Cocos, both posed a significant threat to island birds. Crab-proof bait stations (inset) and other measures have helped rid the island of rats.


Credit: Daniel Vice/USDA-APHIS-WS

Credit: Daniel Vice/USDA-APHIS-WS

A project technician hand broadcasts diphacinone rodenticide as part of a successful multi-year effort to rid Cocos Island of rats in preparation to release captive-bred endangered Guam rails (above), which had gone extinct in the wild. The birds are now breeding successfully.

Eradicating rodents from Cocos presented a technically challenging situation for several reasons. Terrestrial crabs and native forest birds consumed broadcast rodenticide baits. In addition, daily ferries between mainland Guam and Cocos Island created the risk of rodent re-introduction, and a day-use resort on the island created substantial manmade rodent habitat (such as trash stations) that required specialized control approaches. Finally, control activities in close proximity to visitors posed a potential health risk.

Co-author Affiliations Daniel Vice is the Assistant State Director with USDA-APHIS Wildlife Services in Barrigada, Guam. Dana Lujan is a Wildlife Biologist with USDA-APHIS Wildlife Services in Barrigada, Guam. Diane Vice is a Wildlife Biologist with the Guam Division of Aquatic and Wildlife Resources in Mangilao, Guam. Gary Witmer is a Project Leader with USDA-APHIS Wildlife Services’ National Wildlife Research Center in Fort Collins, Colorado.


To help address these issues, project partners identified key needs in the eradication effort and developed an integrated eradication plan, which involved the following steps: Biosecurity. The team drafted and implemented a comprehensive biosecurity plan for the island. This plan involved improving waste management processes; educating resort staff, visitors, and the boating public about the risks of invasive species; installing rodent bait stations on ferry and vendor boats servicing Cocos Island; and inspecting resortbound commodities for rodents and snakes. Trapping. Intensive rat trapping was conducted in and around all trash areas and resort buildings including offices, restrooms, locker rooms, and maintenance buildings. Trapping was also conducted in kitchen and dining areas—where rodenticide baits were not allowed—thereby providing a safe alternative to the use of toxicants in areas where people were cooking and eating. Crab-proof bait stations. We began to distribute the anticoagulant rodenticide containing brodifacoum via crab-resistant bait stations throughout the resort

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settings of the island. The bait stations were made crab-proof simply by affixing a commercially available, tamper-resistant bait station to a five-liter plastic pail, which crabs couldn’t climb. These stations were placed on a 10m-by-10m grid across the resort facility. Each morning, the stations were gathered and stored out of sight, then after the departure of the last tourist ferry, they were set out again. Bait broadcasting. Project managers made two hand-broadcast applications of the anticoagulant Diphacinone 50 Conservation across the forested areas of the island, an area covering approximately 25 square hectares. A rodenticide bait containing diphacinone was chosen because it represented less risk to non-target species. Baits containing other ingredients would likely result in bird mortality. In addition, a hand broadcast was used to place baits more accurately and prevent bait from entering the marine environment. Two one-day broadcast applications were completed seven days apart, placing adequate biat—12.98 kilograms per hectare during the first application and 10.36 kilograms per hectare during the second—throughout the island to target all rodents. Monitoring. Throughout the project, researchers conducted environmental residue testing and intensive monitoring for environmental impacts—including non-target mortality. Monitoring indicated the eradication was completed successfully with no non-target species losses and minimal environmental persistence of anticoagulants. After completion of the baiting program, we conducted post-eradication monitoring using non-toxic baited tracking stations situated around the island. In March 2011—after two years with no sign of rodents—Cocos Island was officially declared rodent-free. This victory enabled the release of captive-bred Guam rails onto Cocos Island, and has allowed the ko'ko' to thrive and reproduce in an environment free of rodents and snakes for the first time since humans colonized Guam. In addition, native forest and seabirds continue thriving across the island, a sure sign that rodent eradication on Cocos Island represents a great step forward for conservation, and a great hope for island ecosystems everywhere.

To see a video about efforts to protect the Guam rail on Cocos Island, go to

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Breaking New Ground The U.S. Forest Service’s New Directive on Invasives By Laura Bies


n December 5, 2011, the U. S. Forest Service (USFS) published the final new National Forest System invasive species management policy (the “directive”), a comprehensive approach to dealing with terrestrial and aquatic invasive species on all 193 million acres in the National Forest System (NFS), which includes national forests and grasslands from Alaska to Puerto Rico. The new directive—Forest Service Manual Chapter 2900: Invasive Species Management—marks the first time that USFS has a policy that addresses all taxa of invasives. It’s also one of the most comprehensive policy documents dealing with invasives that the government has ever produced. The effort took root nearly a decade ago, when then-USFS Chief Dale Bosworth identified invasive species as one of the four key issues facing the NFS. “Public lands—especially federal lands—have become the last refuge for endangered species, the last place where they can find the habitat they need to survive,” said Bosworth. “If invasives take over, imperiled [native] animals and plants will have nowhere else to go.” That pronouncement launched a massive effort within the USFS to craft a strategic response to the invasive species threat. The work began in 2004 with the launch of the National Strategy and Implementation Plan for Invasive Species Management, and culminated with the new directive.

harm or harm to human health.” USFS uses this definition in its directive, meaning that species to be managed under the policy must be both non-native and causing or likely to cause harm, such as impacting the environment through disruption of natural communities and ecological processes, or out-competing native species for food and habitats, thereby leading to less diverse ecosystems. The USFS is unique among federal agencies in having such a detailed policy for dealing with invasive species. It clearly defines roles and assigns responsibility for USFS personnel at all levels of the agency, from the head of the agency through deputy chiefs, program directors, regional foresters, and district rangers. (For a breakdown of responsibilities, go to It also lays out the principles for invasive management within the NFS.

The product of nearly nine years of development, the policy will become part of the agency’s series of directives forming the core of how the NFS is managed. “They’re what we rely on when we make decisions on the ground,” says Michael Ielmini, National Invasive Species Program Manager with USFS. “That’s why it is so important to have a directive dealing with invasive species management.”

Countless Asian lady beetles (Harmonia axyridis) overrun a pine tree in Colorado’s Pike National Forest. Originally from eastern Asia, lady beetles were brought to North America to control aphids.

Weeding Out the Problem

The invasives directive builds off of Executive Order 13112, issued in February 1999, which defines invasive species as “an alien species whose introduction does or is likely to cause economic or environmental

© The Wildlife Society

Courtesy of Laura Bies

Laura Bies is Director of Government Affairs for The Wildlife Society.

Credit: Joe Maskasky/Colorado Parks and Wildlife


The Forest Service directive calls for an integrated pest management (IPM) approach to achieve five overarching objectives: prevention, early detection and rapid response, control and management, restoration, and organizational collaboration. “The focus of the directive on prevention is encouraging,” says Peter Jenkins, Executive Director of the Center for Invasive Species Prevention. “This should mean that the agency can dedicate more resources to preventing the establishment of invasive species in the first place, rather than simply fighting whatever the current invasion is. Once invasive species are established, in our national forests or elsewhere, removal and restoration is costly and time-consuming. Adequate prevention is key.” The directive elucidates 18 policy requirements for achieving these five broad invasive-species management objectives within the NFS. These requirements form the core of the directive and include the following key provisions: • Determine the vectors, environmental factors, and pathways that favor the establishment and spread of invasives in the NSF and design management practices for mitigation. • Determine the risk of introducing, establishing, or spreading invasive species associated with any proposed action, and provide for alternatives or mitigation measures where necessary. • Make every effort to prevent the accidental spread of invasive species carried by contaminated vehicles, equipment, personnel, or materials. • Monitor all management activities for potential spread or establishment of invasive species in aquatic and terrestrial areas of the National Forest System. • Develop and use site-based and species-based risk assessments to prioritize the management of invasives. • Establish and maintain a national record-keeping database system for the collection and reporting of information related to invasive species infestations and management activities. • Collaborate and coordinate with adjacent landowners and other stakeholders to improve invasive species management effectiveness across the landscape.

Next Steps

Now that the basics have been outlined, USFS is developing a handbook that will accompany the directive, which will be a supplemental policy guide articulating the specific standards, guidelines, 36

The Wildlife Professional, Summer 2012

criteria, procedures, and other tactical requirements for implementing the provisions of the new directive. “The handbook is in development now,” says Ielmini. “Once an early draft is ready, we will work closely with tribal government interests to gain their input, and then a proposed draft will be made available for broader public review and comment.” The proposed handbook will likely be ready for review in late 2013. The new USFS directive has broad-based support among the conservation community. In early 2012, the National Environmental Coalition for Invasive Species—a group of environmental and conservation groups (including The Wildlife Society) concerned about the effects of invasive species—wrote a letter to USFS Chief Tom Tidwell in support of the directive. “We thank you again for your leadership on addressing invasive species that threaten our natural heritage,” stated the coalition. “We hope that adoption of the USFS Policy will inspire other federal resource-management agencies to consider adoption of similar policies.” This new directive is not the first federal document dealing with invasive species, however. In 2001, a National Management Plan was prepared by the National Invasive Species Council, established by Executive Order 13112 to provide high-level coordination on invasive species. That council is made up of the secretaries and administrators of 13 federal departments and agencies and co-chaired by the secretaries of Commerce, Agriculture, and the Interior. In addition, the USFS itself has created other documents to offer guidance on invasives beyond the National Forest System, such as its National Strategy and Implementation Plan for Invasive Species, developed in 2004. This plan will soon be revised to reflect changes in USFS policy resulting from the new directive. While other federal agencies have programs and staff assigned to invasives, or at least offer some guidance on their management, USFS is the first to have such a comprehensive, nationwide approach that deals with prevention, detection, and control of all aquatic and terrestrial invasive species. This directive may therefore serve as a blueprint for other land management agencies willing to establish a comprehensive policy to prevent and control the spread of destructive invasive species on the lands and waters they manage. This article has been reviewed by subject-matter experts.

© The Wildlife Society

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Reframing the Concept of ‘Invasives’ By Mark Davis


Courtesy of Mark Davis

Mark Davis is a DeWitt Wallace Professor of Biology at Macalester College in St. Paul, Minnesota.

he persistent negative view of non-native species that has dominated conservation and ecological restoration activities in the United States in recent decades has its roots in the early 1980s, when a group of ecologists interested in species introductions developed a new subdiscipline of ecology now known as invasion biology. For the next 10 to 15 years, most ecologists referred to all nonnative species as “invaders” (Mack 1985, Mooney and Drake 1989). But by framing the redistribution of species as biological pollution by invasives, ecologists presented more than just scientific findings to the public and policymakers: They also promoted a valuebased and prescriptive conservation agenda—stating, in effect, that all non-native species should be eradicated (Temple 1990). That agenda still dominates many conservation initiatives today. I believe the use of invasion terminology has created a bias against non-native species in general. The introduction of new species to a geographic area could be thought of as “species additions” or the “global mixing of species,” terms that are unaccompanied by any value-laden message. Framed this way, the issue of non-native species might elicit management approaches and policies beyond control and eradication. Without question, some non-native pathogens, insects, plants, and animals are “invasive” in that they cause great harm. Most non-native species, however, are not invasive or harmful, but are simply species additions to a particular region without substantial undesirable effects, despite common belief to the contrary. For example, non-native plants growing in eastern North American forests such as garlic mustard, buckthorn, and honeysuckle are commonly described as the cause for declines of native forest wildflowers. However, increasing numbers of recent scientific studies are concluding that the new plant species are not responsible for these declines (Nuzzo et al. 2009, Rooney and Rogers 2011). Instead, the declines are believed to be more often caused by other factors, including the introduction of earthworms (which alter the litter-soil environment) and exploding abundances of white-tailed deer (which eat many native wildflowers) (Nuzzo et al. 2009). Why were non-native plants so quickly declared invasive and the enemy of native plants? One reason was


The Wildlife Professional, Summer 2012

mistakenly assuming a causal relationship between two events happening at the same time (the decline of native plants and the increase in non-native plants). Another was that messages from invasion biologists had led land managers and the public to expect negative effects of non-native species.

A Shift in Perceptions

The general public has never had much of a say as to whether non-native plants should be declared harmful or not. Rather, they have been told at the outset that these plants (e.g., garlic mustard, buckthorn, etc.) are invaders “infesting” our forests and threatening native biodiversity, and that control and eradication efforts—often requiring public tax dollars—need to be undertaken to reduce their abundance. Times are changing, however. More citizens are beginning to question the value-based messages regarding non-native species and the costs associated with eradication. One example: In October 2012, a conference titled “Rethinking ‘invasive species’: Environmentalism gone awry?” will occur in Washington, D.C. I’ve been invited to speak at this event, which is sponsored by Fearless Fund, an organization formed to encourage environmental activism and advance the education and physical, social, cultural, health, and economic well-being of local communities. By reexamining the underlying assumptions and motivations behind the broad campaign against non-native species, the conference hopes to explore creative rather than destructive responses to changes in our environment. By doing so, it will help citizens gain some say in how to assess the harm or worth of newly introduced species, and the strategies developed to manage them. Some public interest groups are already active in this respect. East Bay Pesticide Alert, for example, is an organization in California formed to contest the extensive use of pesticides to control non-native plant and insect species. Public participation in the valuation of and response to non-native species could ultimately result in more effective land management and conservation policy by ensuring that society’s scarce financial and human resources are allocated to projects and programs that best embody and promote the values and priorities of the citizens. © The Wildlife Society

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There’s Nothing Benign about Invasions By Daniel Simberloff


ntroduced predators catch the public’s eye when they devastate native species. The Burmese python in South Florida, for example, has caused greater than a 90 percent decline in prey species such as raccoons and opossums (Dorcas et al. 2012), and the brown tree snake has eliminated 15 of 16 native bird species on Guam (Lockwood et al. 2007). In North America, one of the most damaging invasives is the common carp, introduced as a sport fish in 1887. Carp uproot vegetation, releasing great amounts of sediment (Sorensen and Bergstedt 2011), which transforms clear lakes and wetlands into turbid messes, devastating native fishes and thousands of acres of waterfowl habitat.

More often it is plants that change entire habitats. The toxic “killer alga” Caulerpa taxifolia and its congener C. racemosa have transformed more than 15,000 hectares of seagrass meadows off the coasts of Spain, France, Italy, Croatia, and Tunisia into sterile monocultures, devastating local fisheries (Meinesz 2001, Klein and Verlaque 2008). Likewise, in Florida, forests of Brazilian pepper and Australian paperbark trees have replaced some 200,000 hectares of native sawgrass and muhly grass prairies (Schmitz et al. 1997). Some introduced species appear to benefit conservation by providing habitat or food for rare species (Schlaepfer et al. 2011). However, what looks benign can often turn out to be harmful. In Spain, for example, the Louisiana red swamp crayfish was lauded for enhancing populations of kites and other predatory birds (Tablado et al. 2010), yet roosts of these birds have now killed hundreds of ancient oaks (García et al. 2011). Native species occasionally cause problems, but this happens far less frequently. In the United States, an introduced plant species is 40 times more likely to become problematic than a native species, and the few natives that do become harmful are almost always associated with some human activity, such as overgrazing or fire suppression (Simberloff et al. 2012). To paraphrase Aldo Leopold, eons of evolution adapt native species to their environment, while newly introduced species lacking this coevolutionary history are likely to disrupt the ecosystem (Leopold 1942). © The Wildlife Society

Troubling Time Bombs

The long presence of an apparently innocuous introduced species gives no assurance that it is risk free. Many non-native populations remain small and restricted for decades or longer before exploding across the landscape with devastating impact (Crooks 2005). Introduced plants in Europe, for example, take 150 to 400 years to reach a stable geographical limit (Williamson et al. 2009, Gassó et al. 2010). Such time lags can generate an “invasion debt,” a burden of damage that introduced species may cause far into the future (Essl et al. 2011). In addition, some formerly innocuous non-natives become invasive because of subtle environmental changes (e.g., in climate or hydrology), or upon introduction of another species that facilitates the invader’s spread—the phenomenon of invasional meltdown (Simberloff 2006). In South Florida, for example, the long-harmless Chinese banyan (Ficus microcarpa) became invasive after introduction of its host-specific pollinating wasp (Parapristina verticillata) (Kauffman et al. 1991). Recent molecular genetic research shows that several invaders, such as common reed and reed canarygrass, were innocuous for long periods, only to become highly damaging upon subsequent introduction of new genotypes (Saltonstall 2002, Lavergne and Molofsky 2007).

Courtesy of Daniel Simberloff

Daniel Simberloff is the Gore Hunger Professor of Environmental Science, Ecology, and Evolutionary Biology at the University of Tennessee in Knoxville.

Biologists who study non-native invasions have also detected many ecosystem-wide impacts that are subtle and gradual but nonetheless harmful. For example, some invasive plants increase concentrations of nitrogen (Yelenik et al. 2004) or phosphorus (Turner et al. 2008) in soils, impacting belowground species such as microorganisms and small invertebrates (Loo 2009), and fostering invasion by other introduced species previously restricted by nutrient-poor soil (Vitousek 1986). In sum, any new introduction warrants concern. Proposals for deliberate introductions should be intensely scrutinized, and strong action should be taken to stem newly detected invasions. Success is certainly possible. Dramatic new technologies are leading the way, such as pheromones to control carp (Fine and Sorensen 2008) and microbeads to manage zebra mussels (Aldridge et al. 2006). There is every reason to expect more successes if we continue to take the threat seriously. The precautionary principle mandates no less.


Invasives Package, TWP Summer 2012  

Invasives package from The Wildlife Professional

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