The dynamics of the spatial organization of communities of small mammals (exemplified by rodents of the trans-Altai Gobi of Mongolia)

Between-year variation of rodent population densities was studied in the central part of trans-Altai Gobi, Mongolia, in summers of a nine year period. Variation in spatial structure of the desert rodent community in 1982-84 and in 1992 was examined by the use of discriminant function analysis. Although population densities, breadth and positions of niches of many species tended to vary independently, the positive conjunct variation was found for the most ecologically distinctive species. This can be explained by limitations of the climate. Although a guild structure of the community was pronounced each year, there were significant between year shifts in niche breadth and niche centres along certain axes of ecological space. Within year nearest neighbours in niche overlap (high seasonal overlap) differed in between year variation in abundance. It is supposed that interspecific competition could contribute to development of community structure.