Habitat structure and small mammals abundances in one semiarid landscape in the Brazilian Caatinga

Studies conducted under a major project sponsored by the Brazilian Academy of Sciences in the 1970’s concluded that the small mammal fauna of the semiarid Caatinga region of Brazil is impoverished and highly restricted to mesic granite outcroppings due to the lack of water conserving physiological capabilities in its species. This work focuses the abundance of small mammals in five typical Caatinga habitats. Indirect gradient analysis shows that three theoretical environmental variables explain most of the variance present in the community abundance matrix. Direct analysis of gradients show that none of these variables is highly correlated to availability of granite outcroppings. Our data also suggest that the abundances in Caatinga are not particularly low when compared to neighbor biomes and that underlying factors of habitat use by Caatinga small mammals are more complex than previously supposed.