PARENT SESSION
Oral Session # 71: Trophic Structure I: Theory; Aquatic Systems.
Presiding: D Chalcraft
Thursday, August 7. 8:00 AM to 11:30 AM, SITCC Meeting Room 202.

Evaluation of Crayfish as a Keystone Species.

Brinkman, Robert ^*,1, Burton, Willodean ¹, Hamilton, Steve¹, ¹ Center for Field Biology, Clarksville, Tennessee, United States

ABSTRACT- ABSTRACT A keystone species is critical to a community and has the ability to affect more than one trophic level. Crayfish are ecologically important to small stream ecosystems and have been described as keystone species. They occupy numerous trophic levels and are instrumental in making coarse particulate organic material (CPOM) into fine particulate organic material (FPOM) and available for other macroinvertebrates in streams. Two enclosure/exclosure experiments were conducted in 2002 to test the role of Orconectes placidus as a keystone species. An experiment to determine the impact crayfish have on processing leaf litter was started in February and lasted 28 days. A second experiment, lasting 21 days, to study possible impacts crayfish have on the abundance of other macroinvertebrates was started in May. Orconected placidus significantly reduced the weights of leaf packets they were enclosed with. There were no significant differences in the abundances or richness of macroinvertebrates between crayfish enclosure channels and exclosure channels, used as controls.

Key words: keystone, Orconectes, enclosure, exclosure