Analysis of Spatial Organization of a Desert Rodent Community in Bolson de Mapimi, Mexico

Abstract

We studied the distribution of niches in resource space and niche patterns of a 12-species community of desert rodents by use of canonical-variate and principal-component analyses. Fourteen characters of the environment, measured at 475 sample plots within 19 1-ha grid areas (474 captures of rodents on plots), and eight morphological indicators of niches were used. The first three canonical axes of resource space accounted for 81% of the variance; each of the axes is identified by one of the characteristics of the substrate and one to two characteristics of the vegetation. There was a high level of continuity in distribution of species in the resource space. The lowest values of coefficients of variation of niche overlap and of distances between niche centers characterize a group of the nearest-neighbor species. There was a marked negative correlation of morphological distances to the nearest neighbor with the distances between the same species in the resource space. This evidence indicates certain limitations of ecological similarity of cohabitating species. Negative correlations between niche breadth and the position of the niche in resource space, and between the maximal density of population and niche breadth, are demonstrated.