CS17 Invasive Species
Date: Thursday, June 13, 2002
Time: 12:00:00 PM
Location: Sidney
 
KrauseAE, Michigan State University, East Lansing, USA, krausean@pilot.msu.edu
Mason, D, M, Great Lakes Environmental Research Laboratory-NOAA, Ann Arbor, USA, doran.mason@noaa.gov
 
DISRUPTION OF AN ECOSYSTEM: CHANGES IN ECOSYSTEM PROPERTIES FOLLOWING THE ESTABLISHMENT OF AN EXOTIC MUSSEL IN LAKE MICHIGAN
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The Laurentian Great Lakes make up a unique set of freshwater ecosystems that have been subjected to numerous disturbances in the twentieth century, one of which has been the establishment of exotic invertebrates from ballast water discharges. We examined how ecosystem properties of Lake Michigan changed following the establishment of the zebra mussel (Dreissena polymorpha). Ecosystem models of two time periods, pre-invasion and post-invasion, were developed and their ecosystem properties of structure and function were compared. Ecosystem properties were measured using indices from network analysis. Our results show that ecosystem properties have changed between the two time periods. The amount of energy dispersed through the food web and the organization of that energy within the food web decreased in the post-invasion period. In addition, the percentage of energy passed from one trophic level to the next decreased and recycling of energy through the benthos increased. Further examination showed that at least part of these changes could be attributed to the invasion by zebra mussels.