COMMUNITY STRUCTURE OF DESERT SMALL MAMMALS - COMPARISONS ACROSS 4 CONTINENTS

Presence/absence data for the small-mammal species at sites in seven d eserts were analyzed for evidence of similarity in community structure . The deserts studied were located in North and South America (268 and 118 sites, respectively), Australia (245 sites), Israel (54 sites), a nd greater Eurasia (Thar, 15 sites; Turkestan, 36 sites; Gobi, 98 site s). Patterns observed in all deserts included: (1) low alpha diversity (2-4 species per site); (2) high beta diversity (species turnover bet ween sites); and (3) local coexistence of 20-30% of the species in the regional pool. Additionally, the number of species with which a speci es co-occurred increased with the number of sites at which that specie s occurred. Although these results suggested that some features of com munity structure were similar across deserts, other aspects, especiall y trophic structure, differed widely. Deserts in the northern hemisphe re possessed more granivores, and the Turkestan Desert more folivores, than other deserts. Carnivorous small mammals were most strongly repr esented in Australia, and omnivores in South America, Australia, and t he Thar. The structure of desert small-mammal communities is strongly influenced by historical factors; different taxonomic groups with dist inctive trophic adaptations proliferate in different desert regions wh ere they are subject to some common structuring processes of community assembly.