Publication Date


Document Type


Committee Members

Volker Bahn (Committee Member), Lynn Hartzler (Committee Member), Thomas Rooney (Advisor)

Degree Name

Master of Science (MS)


The Pacaya-Samiria National Reserve of Peru is one of the largest protected areas of the Amazon rainforest, yet it has hosted only a few studies of frogs and toads (anurans). The primary goals of my study are: 1) To conduct an inventory of the local anuran species, 2) to quantify richness among habitats, 3) to compare differences in beta diversity across a river versus a continuous landscape, and 4) to compare difference in body size between nocturnal and diurnal individuals. After eight weeks of daytime and nighttime surveys during the dry season, a total of 601 individuals were identified across 28 species and 6 families. Of these 601 individuals, 50% were found on aquatic vegetation, 29% were found in the forest during the nighttime, and 21% were found in the forest during the daytime. Beyond describing the community composition and species richness, I also quantified the overall diversity and found a difference of body size between diurnal and nocturnal anurans. The overall diversity of the region seems to be mostly from local alpha diversity, but beta diversity was slightly higher than expected when considering populations on opposite sides of the river. This might indicate that the wide rivers of this region are weak barriers of dispersal for anurans. Furthermore, a Wilcoxon rank-sum test showed with great significance that there is a difference of body size between diurnal and nocturnal anurans in this region. This might support theories that anuran species are driven apart by interspecific competition and intraguild predation, or that only larger species can tolerate the cooler temperatures during the nighttime. In conclusion, it would help future studies to spend a greater length of time in the region, to be performed during the wet season as well as the dry season, and to collect data more relevant to explaining any underlying forces influencing the community.

Page Count


Department or Program

Department of Biological Sciences

Year Degree Awarded


Included in

Biology Commons