November 1 2012

5:00 pm BSRB 154

EcoEvoPub Series

Graduate Student Presentations


Greer Dolby
Dept of Ecology and Evolutionary Biology

"Modeling Glacial Refugia for Estuarine Taxa using GIS Remote Sensing and Genetic Data throughout Southern and Baja California"

Abstract: Much work has centered on terrestrial habitat shifts and accompanying adaptation during the Pleistocene’s (2.6-0.01 Ma) dominant glacial-interglacial cycles. Little work, however, has applied such methods and questions to arguably the most affected taxa--those living in estuarine and coastal environments. Using ArcGIS to process satellite imagery (ETOPO1) we model estuarine habitat during glacial lowstands and use these as a priori hypotheses to test genetic signatures of bottlenecking, refugia, and post-glacial secondary contact in mtDNA and microsatellite data across three estuarine fishes. This approach enables us to unite the biological history of these taxa with the geologic context under which they have recently evolved.

Jonathan Chang
Dept of Ecology and Evolutionary Biology

"Increased Future Loss of Biodiversity in Commercially Exploited Ray-Finned Fishes"

Abstract: Commercial harvesting of ray-finned fishes is both intense and widespread. The distribution of this pervasive exploitation and its attendant risk of extinction with respect to phylogeny is not currently well-understood. Previous studies have shown that clustered extinction increases the loss of trait diversity, which has both short-term (lower yield, reduced ecosystem services) and long-term effects (lost evolutionary history, biodiversity). Our earlier results showed a highly significant clustering of extinction risk and exploitation pressure among many ray-finned fish clades. Here we examine whether this pattern of clustered extinction risks increases the loss of evolutionary history compared to a pattern of random extinction. We also analyze the rate of body size evolution to test whether at-risk species tend to enjoy a significantly faster rate of body size evolution. These findings, in conjunction with a potentially high loss in evolutionary history, suggest that commercial harvesting may prune away particularly exceptional branches on the fish tree of life.

THURSDAY, November 1, 2012











































































































































































































































































































































































































































































































































































































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