Doctor of Philosophy (PhD)


Biological Sciences

Document Type



The Amazon rainforest encompasses over one billion acres of South America and sustains remarkable biodiversity. Despite the large body of research stemming from this region, little is known about the effects of geomorphology and primary productivity on the fauna of Amazonia, and on reptiles and amphibians in particular. In my dissertation, I examine differences in the abundance, biomass and species richness of secondary consumers in the leaf litter herpetofauna communities on young and ancient soils. Herein, I develop methods to utilize existing data sets and museum collections in new studies involving community biomass. I found that, although the process of preservation does change the size of specimens, for most species the differences are less than 4%. Furthermore, these changes can be quantified and taken into account when applying measurements made on preserved specimens to studies of living individuals. I also derive equations which can be used to calculate mass from length in anurans. Snout-vent length (SVL) has been measured on thousands of herps, some released in the field and many housed in research collections. Estimated using SVL measurements, mass of individuals can now be used to determine community biomass of populations that were initially sampled for other purposes. In the second half of this dissertation, I assess the effects of geomorphology on leaf litter herpetofauna in Neotropical lowland rainforests. At sites with similar latitude, elevation and climate, litter herpetofauna abundance, biomass and species richness are twice as high on younger soils. Using methodology developed in the first chapters, this comparison is expanded to include forests differing in latitude and climate. In this study, the trend of increased density, biomass and diversity on younger soils holds, lending further support to the hypothesis that geomorphology and primary productivity drive leaf litter herpetofauna community dynamics. These studies taken together provide the basis for a change in Amazonian management strategies. The prevailing notion that a few large reserves within the Amazon will be able to sustain Amazonian biodiversity is unfounded. Reserves and conservation policy must be designed around the local geologic history and forest dynamics of forest regions within the Basin.



Document Availability at the Time of Submission

Student has submitted appropriate documentation to restrict access to LSU for 365 days after which the document will be released for worldwide access.

Committee Chair

G. Bruce Williamson