Geographic variation in densities and diversities of non-flying mammals in Amazonia
Biotropica
1984
Journal Article
16
3
210-222
Parque Nacional del Manu Cocha Cashu Reserva Nacional Tambopata animals mammals inventories abundance community structure diversity large spatial scales ecology Brazil Ecuador soils climate competition territorial behavior diet hunting Madre de Dios Bibliography
The results of the evaluation of non-flying mammals at seven localities of Ecuador, Brazil and Peru (Cocha Cashu, Yanamono, Mishana and Tambopata) are presented. Trapping and transect census were made during day and night, in localities of mature ever green tropical forest. The objective was to compare the relative number of individuals and species of mammals of the studied localities. The relative number of individuals from small species varies substantially from one locality to another, while the large species remain constant. The variation pattern of the number of species oberved is reflected in the differences of species richness between the western Amazonia and the Guiana Shield region of Brazil, suggesting that similar environmental facts will regulate the number of species and of individuals in one locality. Soil fertility and undergrowth density are positively correlated with the density and species richness of mammals in a locality, but pattern of rainfall does not seem to account for any of the observed differences. Competition, home range size and diet are discussed as possible causes of differential reduction in density and species richness of small, compared to large species in unfavorable habitats. It is also observed that in the studied localities, hunting has exterminated or severely reduced populations of large mammals, especially primates.