Spatiotemporal microhabitat heterogeneity and dispersion patterns of two small mammals in a temperate forest

Abstract

One of the basics and fundamentals problems in ecology is understand the factors that shape the spatial patterns in the distribution of the species and the coexistence of close relatives species. Among the most important factors governing the distributions and the coexistence of species are the spatiotemporal changes occurring in the microhabitat heterogeneity. Here, we assessed the heterogeneity of microhabitats and how they have an effect in the spatial segregation of two species of small mammals (i. e., Peromyscus difficilis and P. melanotis), which coexist in a temperate, mixed forest. We evaluated the microhabitat heterogeneity through multivariate statistics, using onto 23 habitat variables for vertical-horizontal habitat structure along pluvial seasons. To detect specific microdistribution changes and habitat preferences by two species of small mammals, we used second order spatial statistics and general linear models. According to their respective morphology and locomotive adaptations, the middle sized, midscansorial P. difficilis was resident all year long and preferred microhabitats with a high log ground cover, while the opportunistic, small sized, cursorial P. melanotis changed its occupancy area, depending on density of herbaceous and woody plants cover. Under the more benign microhabitat conditions of rainy season (denser plant coverage, milder temperature), both species showed closer microdistribution patterns; while these became repulsive at the less benign conditions of dry season (scarcer plant cover, colder temperature). Thus, we could confirm that seasonal changes of microhabitat heterogeneity promoted Peromyscus coexistence, through dispersion patterns reflecting partition of microhabitat resources.