PARENT SESSION
Poster Session # 21: Biogeography, Biodiversity, Populations, and Genetics.

Thursday, August 7 Presentation from 5:00 PM to 6:30 PM. SITCC Exhibit Hall B.

From coast to highlands: An elevation gradient survey of rodent communities in southwestern Peru.

Gladwell, Randi^*,1, Ihue-Umire, Yenny², ¹ University of New Mexico, Albuquerque, NM, USA² Universidad de San Augustin, Arequipa, Arequipa, Peru

ABSTRACT- A small-scale survey of rodent communities was conducted during July 2002 in three locations (Camana, 60 masl; Aplao, 650 masl; and Chuquibamba, 2700 masl) in the department of Arequipa on the western flanks of the Andes Mountains in Southern Peru. The goal was to explore ecological and historical impacts on plant and animal species by humans and human associated activities. We documented the species diversity within rodent and plant communities present in the narrow river valleys of the Majes Drainage System; an area highly modified by humans practicing agriculture for more than 1500 years. With the exception of El ino events, there was no significant precipitation on the west coast of Peru due to geographic and climatic factors that involved the combination of the Humboldt Current and rapid ascent of the Andes Mountains. As a result, these western slope river valleys are ecologically constrained due to this limited access to water and the biota depends on water originating from the highlands. Vegetation is limited only to the bottom of narrow river valleys and rarely grows on valley slopes. With supporting archaeological evidence, our findings suggest that commensal rodents (e.g., Mus musculus and Rattus rattus) that arrived with Europeans have aggressively replaced endemic rodent communities from these low elevation valley bottoms. Higher elevation rodent communities have greater species diversity and no commensal rodents were encountered, possibly due to geographic barriers. The hypothesis that climatic change is an agent and factor of ecological changes suggested here has not been falsified.

Key words: Rodent Communities, Human Impact, Peru, Elevation Gradient