Document: STE-3-50-8

The effect of habitat and behavior on burrow structure of two species of pocket gopher.

ROMAŅACH, S.* ¹, E.SEABLOOM ² and O.J.REICHMAN ^1,2

University of California, Santa Barbara, CA 93106, USA ¹
National Center for Ecological Analysis and Synthesis; Santa Barbara, CA ²

Abstract:
In many animal species, the densities and abundances of individuals are determined by (1) resource abundance, (2) body size, and (3) social interactions. Subterranean animals should be particularly affected by resources and body size because of their energetically expensive lifestyle. For example, the cost of constructing burrows for pocket gophers is 360-3400 times as costly as moving on the surface. The energetic expense is highly variable and dependent on soil characteristics and body size, but less is known about the influence of social interactions. Existing data for a single species suggest that pocket gophers maintain uniform between-burrow spacing as well as within-burrow geometry across wide ranges of resource and habitat features. This consistency implies that burrow spatial patterns may be mediated through social interactions. To test this hypothesis, we examined physical characteristics of previously excavated burrow systems distributed across sites in Arizona, Kansas, and Minnesota. The burrows were constructed by two species of gopher (Thomomys bottae and Geomys bursarius) that differ greatly in body size. To determine burrow configurations, we measured several metrics of burrow geometry such as total burrow length and branching angles. We found few differences among burrow systems of the two species across locations. This finding supports the suggestion that gophers maintain burrow features independent of habitat and species characteristics.

Keywords: pocket gopher; burrows; burrow geometry; spatial pattern; social interactions

This abstract is being presented at: 8:45 AM in session:
Oral Session #21: Small Mammal Population Ecology.