Thursday, August 5, 2010: 2:10 PM
411, David L Lawrence Convention Center
Travis C. Haas1, Michael J. Blum2 and David C. Heins1, (1)Ecology & Evolutionary Biology, Tulane University, New Orleans, LA, (2)Ecology and Evolutionary Biology, Tulane University, New Orleans, LA
Background/Question/Methods Water impoundment imposes fundamental changes to natural landscapes by transforming rivers into reservoirs. The dramatic shift in physical conditions accompanying the loss of flow imposes novel ecological and evolutionary challenges to native species. In this study, we used geometric morphometric analysis to compare the body shape of Cyprinella venusta, a cyprinid generalist, collected from eight pairs of river and reservoir sites across the Mobile River Basin (USA).
Results/Conclusions
Individuals inhabiting rivers are more shallow-bodied and have larger heads, more posterior dorsal fins, a longer dorsal fin base, and a more anterior-dorsal position of the eye than C. venusta in reservoirs. The direction of shape divergence within reservoir-river pairs was consistent among pairs of sites, and the shape of C. venusta in reservoirs is strongly correlated with reservoir size. These findings show that physical characteristics of reservoirs drive changes in the morphological attributes of native fish populations, demonstrating that water impoundment may be an important, yet largely unrecognized, evolutionary driver acting on aquatic biodiversity worldwide.
