The Home Range and Population Biology of the Oregon Salamander, Ensatina eschscholtzii oregonensis, in the Reed College Canyon
author: Nathalie Jeanne Etienne Jacqmotte
advisor: Robert Kaplan
ABSTRACT: The population biology and home range of the Oregon salamander, Ensatina eschscholtzii oregonensis, were studied in the Reed College canyon. Animals were individually marked and their path lengths were measured. Path lengths were obtained from dusting animals with fluorescent pigment and tracing the path with ultraviolet light after 24 hours. Home range size, measured by path length and distance between recapture points, was studied in relation to age, sex, secondary sexual characteristics, size, weight, tail autotomies and density. Juveniles had significantly shorter path lengths than adults, which is indicative of their minimizing risks of desiccation and predation to which they are more vulnerable. Males and females with secondary sexual characteristics had significantly shorter path lengths than those animals without secondary sexual characteristics. This reflects the reduced mobility of gravid females and increased territoriality among males with secondary sexual characteristics. Path lengths were not related to weight or adult size, so the energetic model of home range developed by McNab (1963) relating home range size to weight can be rejected. Calculated home ranges ranged from 0.038-2.60 m2. These were considerably smaller than those found in another population of Ensatina by Stebbins (1954). This study resulted in the characterization of the population biology of a previously unstudied population.