Morpho-ecological structure of desert rodent communities in Central Asia and southwestern North America: a multivariate approach

Abstract

The principal components analysis and the cluster analysis were used tostudy the morpho-ecological organization of four desert rodentcommunities from Mongolia (Trans-Altai Gobi and Gobi-Altai) and Mexico(Central Chihuahua and Sonora). Twenty characters of external morphologyof 41 species (representatives of 54 populations) were put intoanalysis. Results demonstrate a relatively low level of convergencebetween Mongolian and Mexican species. Rodent species of Mongoliancommunities occupy a bigger volume of the factorial space than rodentspecies of Mexican communities, although the number of species in bothtypes of communities is similar. The comparison of Euclidean distancesto the nearest neighbour and their coefficients of variation in realgroups of coexisting species (at the level of habitat) and inhypothetical groups formed by random combination of species points tothe pattern of regularity in species packing. At the same time there aredifferences in species distribution in morphological space of Mongolianand Mexican communities. The significant positive correlation ofEuclidean distances in morphological and in ecological space (distancesbetween centers of spatial niches) was shown in the community ofMongolian rodents. There is no such correlation in the Mexican rodentcommunity. Predators and environmental conditions could be expectedinfluencing community formation in deserts of Central Asia whereas indeserts of North America the role of interspecific competition is moreprobable.