October 18 2012

5:00 pm BSRB 154

EcoEvoPub Series

Graduate Student Presentations


Pam Thompson
Dept of Ecology and Evolutionary Biology

"Does Forest Fragmentation Matter for Bats? Data from Bat Pollinators and the Bat-Pollinated Tree, Crescentia alata"

Abstract: The impact of forest fragmentation on the connectivity of plant populations, and their animal pollinators, is a key question in conservation biology. Highly mobile animals, such as bats, can transport pollen long distances, and may mitigate the impacts of fragmentation if these animals are not inhibited by landscape change. This study evaluates the impact of the landscape type (fragmented or intact forest) on bat pollinator abundance, and whether bat pollinator presence enhances plant reproductive success in the tree species, Crescentia alata, in a tropical dry forest in Mexico. A total of 366 nectarivorous bats were mist-netted near flowering C. alata trees in different landscape types, over the month-long flowering period of this tree species. The number of nectarivorous bats caught was significantly and positively correlated with the number of open flowers, demonstrating that bat pollinators are able to track this resource. The number of bats caught did not differ significantly between landscape types, except for the species Choeroniscus godmani, which was only found in intact forest, suggesting that the other two nectarivore species are not negatively impacted by forest fragmentation. Reproductive success of C. alata was measured by the ratio of fruit to flowers produced, and was significantly higher in fragmented forest sites. The most abundant nectarivorous bat caught, Glossophaga sp., had a significant effect on reproductive success. However, Leptonycteris yerbabuenae, the second most abundant nectarivore, appears to be a more effective pollen transporter than the Glossophaga species, based on pollen presence data. These findings highlight the complex species interactions at work in this pollination system, and suggest that bat pollinator behavior may exhibit some degree of resilience to forest fragmentation.

Sarah Ratay
Dept of Ecology and Evolutionary Biology

"Deciphering the Baja California Contributions to the Flora of the Channel Islands"

Abstract: A subset of plant species occurring on the Channel Islands of California have native occurrences on the islands or mainland of Baja California, without representation on the adjacent Southern California mainland. What is precluding these species from occurring on the mainland of California? To identify these species, a composite of published species lists from each island group (California and Baja California) was compiled, and these lists were compared to the mainland California flora to generate a list of plant species exhibiting this unusual pattern. We have identified twenty species with this intriguing distributional pattern, including some species with special protection in the state of California. This list of exemplar species will be presented alongside the complied species lists for all islands occurring in the California Floristic Province. Further work will address emergent species traits and ecological patterns in these shared insular taxa, to better resolve the roles of geologic history, dispersal patterns, and plant evolutionary processes. Emphasis will also be placed on the international conservation significance of these unique species found on both sides of the geopolitical border.

THURSDAY, October 18, 2012











































































































































































































































































































































































































































































































































































































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