Habitat Discrimination between Sympatric Populations of Peromyscus attwateri and Peromyscus pectoralis in West-Central Texas

Abstract

Habitat discrimination between sympatric populations of Peromyscus attwateri and P. pectoralis was examined through live trapping, observations of escape cover, and fluorescent tracking. Discriminant-function analysis of live-trapping data defined the position of each species along a habitat gradient ranging from sloping limestone ledges with leaf litter under a live oak (Quercus fusiformis) canopy to more open grassy areas with scattered rocks and young mesquite (Prosopis glandulosa). P. attwateri was a generalist using the full range of available microhabitats. P. pectoralis specialized on areas of limestone ledges and leaf litter, and its microhabitat niche was included entirely within that of P. attwateri. Results of analysis of escape cover and fluorescent tracking for P. pectoralis confirmed the association of this species with limestone ledges. Both discriminant-function analysis and fluorescent tracking indicated that immature P. pectoralis used marginal habitats in addition to limestone ledges, therefore had a broader microhabitat niche than adults. Observation of escape cover and tracking revealed that on the study site, P. attwateri is at least semiarboreal and travels primarily in trees.