In its review of the status of the Illinois cave amphipod, the Service found that the number of cave systems known to be inhabited by the animal has decreased from six to three. In addition, the water quality in the cave streams where the amphipod lives is threatened by pollution from a number of sources, including pesticides, fertilizers, animal waste, and septic systems.
The Illinois cave amphipod is a tiny creature, but its role in cave ecosystems is large, said Service Regional Director Bill Hartwig. Because it is so tied to the aquatic environment, it is an excellent indicator of how healthy the water is that supports wildlife, livestock, and people in this area.
The listing action triggers the development of a recovery plan to guide conservation actions and the restoration of populations of the Illinois cave amphipod. The Endangered Species Act provides protection of listed species from take, which includes killing, harming or harassing. In addition, Federal agencies whose actions may affect the amphipod will consult the Service before undertaking activities that might harm the species.
The Illinois cave amphipod is a small, gray-blue crustacean measuring less than an inch long. It inhabits streams which run through caves, living in dark zones and feeding on dead animal and plant matter, and bacterial film covering submerged surfaces. It was historically known to occur in six cave streams in Monroe and St. Clair counties in Illinois, but is now known to inhabit only three of these streams. It may also be present in a fourth, but the cave is not accessible for surveys. Main entrances to two of the caves are in state ownership; other entrances are privately owned, with one a dedicated nature preserve.
The area in southwestern Illinois where the cave amphipod is found is characterized by karst, a geological formation featuring sinkholes, underground streams and caves. Such areas are extremely vulnerable to groundwater pollution and changes in water runoff, as contaminants enter the system through sinkholes and are quickly dispersed through underground streams. The area inhabited by the Illinois cave amphipod is just across the Mississippi River from metropolitan St. Louis, a region that is experiencing increased development of residential areas using septic systems.
The primary mechanism leading to the decline of the species may be a reduction in dissolved oxygen in the cave streams. While rainfall events naturally reduce dissolved oxygen levels in cave streams, human activities on the land surface result in more rapid surface runoff, faster and more precipitous drops in dissolved oxygen, and the additional simultaneous stresses from pesticides and the biological oxygen demands of nitrogen-based fertilizers and organic wastes. Agricultural chemicals may either be lethal in themselves at certain concentrations, have chronic effects (e.g., reproductive impairment), or can leave the amphipods in a weakened condition and less able to cope with short-term depressions of dissolved oxygen.
While the Service acknowledges that these are complex and potentially controversial threats to the amphipod, the agency expects that impacts can be reduced through modest land treatments. They include creating buffer strips around sinkholes, ensuring chemicals are not dumped in sinkholes, and that livestock waste is not allowed to leak into sinkholes. The Service also anticipates improved guidance from other Federal agencies on pesticides use near caves. The Service will work with the Department of Agricultures Natural Resource Conservation Service, local agricultural representatives, and landowners to develop voluntary conservation agreements designed to protect surface and groundwater quality. Likewise, the Service will work with local developers, planning and zoning boards, and health departments to ensure that effluent from residential septic systems is not directed into sinkholes.
The Services final rule listing the Illinois cave amphipod as endangered appears in todays Federal Register. For more information on the Illinois cave amphipod, or information on how to safeguard water quality and conserve cave species such as the amphipod, contact the U.S. Fish and Wildlife Service, 4469 48th Avenue Court, Rock Island, Illinois 61201, or call 309-793-5800 ext. 520. Information is also available at the Illinois cave amphipod website at http://www.fws.gov/r3pao/rock_is/activity/endangrd/ilca.html.
The U.S. Fish and Wildlife Service is the principal Federal agency responsible for conserving, protecting and enhancing fish, wildlife and plants and their habitats for the continuing benefit of the American people. The Service manages the 93-million-acre National Wildlife Refuge System which encompasses more than 530 national wildlife refuges, thousands of small wetlands and other special management areas. It also operates 66 national fish hatcheries, 64 fishery resource offices and 78 ecological services field stations. The agency enforces Federal wildlife laws, administers the Endangered Species Act, manages migratory bird populations, restores nationally significant fisheries, conserves and restores wildlife habitat such as wetlands, and helps foreign governments with their conservation efforts. It also oversees the Federal Aid program that distributes hundreds of millions of dollars in excise taxes on fishing and hunting equipment to state fish and wildlife agencies. For further information about the programs and activities of the U.S. Fish and Wildlife Service in the Great Lakes-Big Rivers Region, please visit our home page at: http://midwest.fws.gov
