Capybaras in an anthropogenic habitat in Southeastern Brazil.

Capybaras (Hydrochoerus hydrochaeris) are widely distributed in the Neotropics, living in both natural and anthropogenic habitats. In the present study, we monitored the fluctuating capybara population at the Campus "Luiz de Queiroz", University of São Paulo, in Piracicaba, Southeastern Brazil from 1998 to 2000. To assess population fluctuation and growth rates, we used an abundance index based on direct weekly daylight counts. Population monitoring was carried out in an anthropogenic wetland associated with an agroecosystem. The observers bias was established as directly related to their distance from the animals. The capybara population density and biomass in the anthropogenic wetland in question were found to be significantly higher than in pristine habitats. The species seems to present a seasonal pattern of fluctuation, with a peak in late spring (Oct to Dec). Unlike young capybaras, adults and juveniles present similar seasonal fluctuation patterns. In this anthropogenic wetland, the carrying capacity may be as high as 195 individuals/Km2. At a conservative exploitation rate (17%) in anthropogenic wetlands of Southeastern Brazil, capybara productivity may reach approximately 630 Kg/Km2/year.