Redistributed as a Service of the National Library for the Environment*
Harmful Non-Native Species: Issues for Congress II
April 8, 1999
Brown tree snakes from the western Pacific threaten power utilities and communications on Guam and the Northern Marianas, and seem ready to invade Hawaii and harm its enormous tourism industry. Zebra mussels from eastern Europe clog intakes for urban water supplies and nuclear power plants in the Great Lakes and the Mississippi basin. Fonnosan termites devastate living trees and historic buildings of New Orleans' French Quarter. Leafy spurge slashes the forage value of western grazing land, thereby creating precipitous drops in land value.
To continue with a full list of the damaging effects of harmful non-native plants and animals risks sounding like hyperbole. Only in fairly recent years have people realized that various areas of the country share problems that are similar in outline if not in detail. Impacts have been severe on agriculture particularly. The globalization of trade, increased speed of travel, and cargo shipments, plus rising tourism all combine to increase the chance of more accidental introductions. Moreover, trade in exotic plants and animals which would have been impractical in voyages that take days, now becomes practical when shipment times are only a fraction of that. Some of the species in the horticulture and exotic pet trades may be released in the wild by accident or when owners tire of them.
All 50 states and all of the territories have at least some non-native plants and animals. A few (e.g., Alaska, Maine, Minnesota) have relatively few non-natives, while others (e.g., Hawaii, Florida, Louisiana, California) have so many harmful non-natives as to cause major ecological and economic damage to a variety of locations and industries. Problems with non-native species tend to be more severe in the southern half of the country in terms of total numbers of non-native species.
Estimating the total economic impact of harmful non-native species is extremely difficult. No federal agency accumulates such statistics comprehensively. One estimate put damage at $123 billion annually. 1 Including cost of control, damage to property values, health costs, and other factors, the following are the costs of selected species (each covered individually in A Gallery of Harmful Non-native Plants and Animals at the end of this report):
Many impacts would be extremely difficult to measure in monetary terms. The introduction of lake trout into Yellowstone Lake (see Gallery; below), for example, is likely to have profound effects on populations of grizzly bears, bald eagles, and native cutthroat trout. The presence of honeybee mites (see Gallery, below) is equally problematic. On the one hand crops pollinated by honeybees (itself a non-native species) will be more difficult to raise. On the other, native species of bees may benefit from the absence of competition, and the presence of mites may be slowing the northward spread of Africanized honeybees, also a non-native species (see Gallery).
Because the problem of non-native species has continued to present itself as a series of seemingly disconnected crises and species, legislation has also become a patchwork, as each crisis was addressed. The laws addressing threats to agriculture (for centuries a well-developed North American industry whose risks from non-native invasions are relatively clear) tend to be more developed than laws protecting other industries, or protecting ecosystems. In consequence, agencies whose mission is to address those risks are also better-developed. Yet even there, responsibilities to protect agriculture from non-natives which are established in some regions but not others are diffuse, shared, or even lacking. Moreover, the volume of trade makes the burden on understaffed federal inspection systems so severe as to permit only cursory inspections, and force a strong reliance on self-reporting by shippers of living and non-living cargo.
But laws protecting industries such as tourism, the electric power industry, or city water supplies are far less developed. In some important instances, such laws scarcely exist at all. A state agency which wishes to bring in a sport fish from another continent to benefit its anglers may face few obstacles in doing so, much less a burden of proof to show that the action will not harm other economic interests, natural resources, or ecosystems.
No comprehensive U.S. law addresses imports of non-native species. No burden of proof lies generally with those importing living organisms (other than those known to threaten agriculture) to show that the imported species is safe. Indeed, some laws force the burden of proof in the other direction. an import is deemed safe unless it is on a list of organisms known to be harmful. Special laws to control imports of exotic aquarium fishes or pets, and the disposal of those pets once owners tire of them, are lacking, or may be focused on some other issues (e.g., effects on populations of wild birds in the exporting country rather than in the United States).
Non-native species introductions can be divided into those which were intentional, or at least known by the person bringing in the living organisms, and those whose arrival was probably not known to the persons involved. While there may be disagreement over which species should be excluded among the many species whose entry is sought, there appears to be no constituency for unintentional imports. Rather, opposition, if any, results from the effects of regulations on trade or travel generally that might arise from efforts to prevent introductions. Therefore research on which pathways pose the greatest risks, and on the least intrusive mechanisms to reduce those risks, could offer substantial benefits with reduced harm to trade and travel. With the possible exception of controls on ballast water, little has been done legislatively to identify or control high risk pathways. Experts suggest that Congress consider requiring studies to identify both high risk pathways and methods to reduce inconvenience of control measures to travelers and shippers using those pathways. Untreated wood, airline cargo holds, ship hulls, used tires, etc. are among possible targets for broader risk assessment or controls.
Executive Order 13112. In response to rising concern, especially in southern and western states plus Hawaii, President Clinton signed Executive Order 13112 on Invasive Species (64 Fed. Reg. 6183, Feb. 8, 1999), on February 3, 1999, revoking President Carter's 1977 Executive Order 11987 on exotic species. 2 The new Executive Order seeks to prevent the introduction of invasive species 3 and provide for their control and minimize their impacts through better coordination of federal agency efforts under a National Invasive Species Management Plan to be developed by an interagency Invasive Species Council. The Order directs all federal agencies to address invasive species concerns as well as refrain from actions likely to increase invasive species problems. The Invasive Species Council, supported by an advisory committee, is also to develop recommendations for international cooperation, promote a network to document and monitor invasive species impacts, and encourage development of an information-sharing system on invasive species. (See below for more information.)
S. 83 and S. 321 have been introduced in the 106th Congress to (1) permit the Animal and Plant Health Inspection Service (APHIS) to address all types of weed issues, not just new or recent introductions; (2) facilitate the listing of any weed that is of regulatory concern regardless of origin; (3) increase the maximum civil penalty to $50,000 per violation for individuals and to $250,000 for businesses; and (4) authorize APHIS to take both emergency and extraordinary emergency actions to address incursions of noxious weeds. The bills do not increase APHIS' responsibilities regarding invasive species harmful to fish and wildlife resources, nor do they cover introduction of non-native animal species, except insofar as these species are likely to be plant pests. 4 (See Coverage of Laws and Policy, below.)
1 David Pimentel, Lori Lach, Rodolfo Zuniga, and Doug Morrison. Environmental and Economic Costs Associated with Non-indigenous Species in the United States. Presentation at American Association for the Advancement of Science, Ananeim, CA, January, 1999. For text, see http://www.news.cornell.edu/releasesljan99/species_costs.html (Hereafter referred to as Pirnentel report.) Costs estimates in the study included weeds, crop disease, rats, insect pests, non-native diseases of humans, zebra mussels, and a variety of other species and categories. Domestic and feral cats and dogs were included, and accounted for 4.9% and 0.1% of the total, respectively.
2 For more information on the legal status of Executive Orders, see CRS Rept. 95-772 A, Executive Orders and Proclamations.
3 Invasive species are defined in § 1 of the Executive Order as "alien species whose introduction does or is likely to cause economic or environmental harm or harm to human health."
4 In the l05th Congress, a similar bill (H.R. 3766) was introduced by Rep. Canady, but it has not been re-introduced in the 106th Congress.
5 U.S. Congress Office of Technology Assessment. Harmful Non-Indigenous Species in the United States. OTA-F-565Washington, DC: U.S. Government Printing Office, September 1993. p. 3-5. (Hereafter referred to as "OTA Report."
6 Pimentel report.
|National Council for Science and the Environment
1725 K Street, Suite 212 - Washington, DC 20006
202-530-5810 - info@NCSEonline.org