Clubshell (Pleurobema clava) from the Tippecanoe River in Fultpn County, Indiana.
(Photo by Kevin Cummings)
Most Illinoisans are familiar with such endangered species as bald eagles, bobcats, or river otters, but they are probably not as familiar with less "charismatic" endangered species like salamanders, dragonflies, crayfishes, or mussels. Also, many people are aware that certain types of ecosystems-- tallgrass prairie, oak savanna, or wetlands like bogs or fens--are disappearing. While these are important ecosystems that certainly should receive protection, INHS scientists and others across North America have found that aquatic ecosystems, particularly streams, continue to be degraded and are in need of stronger conservation measures.
The decline in aquatic organisms is much greater than that documented for terrestrial species and attests to both the magnitude of the problem and the inadequacy of water protection measures in Illinois and across the United States. Over 22 percent of the threatened and endangered species in Illinois are associated with aquatic habitats, including more than 67 percent of all state-listed animals.
The Illinois Natural Areas Inventory and Illinois Nature Preserves system have been highly successful in identifying and protecting representative examples of nearly all major terrestrial habitat types and communities in Illinois. As of August 1995, 236 sites totaling over 30,350 acres have been dedicated as Illinois Nature Preserves. These dedicated lands provide habitat for many rare terrestrial species. However, only one stream segment has been designated as an Illinois Nature Preserve, and less than 6 percent of all known occurrences of threatened or endangered aquatic species in Illinois occur within waters flowing through Illinois Nature Preserves.
The plight of freshwater mussels is a prime example of the decline of aquatic habitats and the species that inhabit them. North America has the most diverse freshwater mussel fauna in the world. Nearly 300 species of mussels are known from the U.S., and over 90 percent of these are found east of the Rocky Mountains. Recent stream surveys throughout the U.S. have documented drastic declines in mussel populations; indeed, mussels may be the most endangered group of animals in North America.
Clubshell (Pleurobema clava) from the Tippecanoe River in Fultpn County,
Indiana.
(Photo by Kevin Cummings)
Through examination of over 61,000 specimens in mollusk collections in museums across the U.S. and by compiling data from scientific literature, INHS biologists have documented that 80 species of mussels were once present in Illinois waters. The streams of Illinois have been severely affected by pollution and siltation, and since 1970, only 59 mussel species have been found in the state. Eleven of the remaining 59 species are now known from a single river system or population. There is some evidence that some of these endangered mussels may not be reproducing and could be lost by the end of the century.
A grant to INHS biologists Kevin Cummings and Christine Mayer from money donated to the Wildlife Preservation Check-off Program of the Illinois Department of Natural Resources (DNR) is providing funds to help determine the status of the clubshell (Pleurobema clava). This mussel, which was listed as a federally endangered species on 22 January 1993, now occurs in only a few streams in the Midwest. In Illinois the clubshell was once a common species in the Vermilion and Wabash rivers. A review of specimens collected as part of a survey conducted on the Vermilion River by INHS biologists in 1980 suggested that this species may still occur in the North Fork of the Vermilion River in Vermilion County. A preliminary search was conducted last summer with the help of DNR Natural Heritage biologist Bob Szafoni. Although no living clubshells were found, a few valves in relatively good condition provided hope of finding it when we return this summer. The results of the search were not all negative because we verified the presence of four other Illinois endangered mussels living in the river.
Kevin Cummings and Christine Mayer, Center for Biodiversity
Next Article
Index
to This Issue
Index to
Survey Reports
INHS Home Page
Please report any problems with or suggestions about this page to:
inhspubs@mail.inhs.uiuc.edu
Subject: INHSPUB-00414
Last Modified 4/24/96