Assessing The Demography And Conservation Genetics Of Asian Vultures Using Non-Invasive Molecular Techniques
Asian vultures are undergoing widespread population declines and several species are listed as critically endangered. In spite of this conservation crisis, there is little information on the demography and genetics of any species. This is largely because vultures are very difficult to study using conventional methods: individuals breed irregularly, non-breeders are itinerant, and all vultures can travel hundreds of kilometers to forage. To overcome the challenges of studying vultures using traditional methods, I obtained genotypes derived from non-invasively collected feather samples as an alternative means to 'capture' individual vultures for demographic and genetic analyses. I analyzed samples from three species in Southeast Asia, Gyps bengalensis, G. tenuirostris, and Sarcogyps calvus, whose populations have been greatly reduced and geographically restricted in Cambodia. I also collected feathers from two species in Kazakhstan, Gyps himalayensis and Gyps fulvus. In my first dissertation chapter, I described a restriction endonuclease digest assay that distinguishes the visually similar feathers of the five vulture species, and I described a panel of 8 polymorphic microsatellite loci that I used for subsequent analyses. In my second chapter, I analyzed microsatellite loci and mitochondrial DNA to assess the genetic diversity of the three species found in Cambodia. I found that G. bengalensis, despite having a small population size, showed relatively high levels of genetic diversity, whereas G. tenuirostris and S. calvus had lower levels of genetic variation. In addition, I compared the genetic structuring of G. bengalensis in Cambodia with samples collected from individuals in Pakistan in 2000/01 and found that the two populations have significant levels of population differentiation. For my third chapter, I used DNA from feathers for genetic capture-mark-recapture analyses for the three vulture species in Cambodia and for G. himalayensis G. fulvus in Kazakhstan. I used closed capture models to generate abundance estimates for G. bengalensis and G. himalayensis but lacked the requisite statistical power for the remaining three species due to low resampling rates. Overall, my research identified aspects of vulture biology previously not studied and provides the methods that can be used to further investigate the biology of these threatened avian scavengers.
vulture; mark-recapture; conservation genetics
Lovette, John I
Cooch, Evan G.; Winkler, David Ward; Clum, Nancy Joan; Katzner, Todd
Ph.D. of Evolutionary Biology
Doctor of Philosophy
dissertation or thesis