Population Estimate and Spatial Distribution of Capybaras in Lake Paranoá, Brasília, Brazil

Abstract

The capybara is the largest living rodent, attracting attention due to its large size, its formation of large herds, and because it is commonly seen in urban environments. Thus, understanding the dynamics of capybara populations living in urban environments is relevant, especially given the conflicts observed between the species and humans in these environments. Here, we investigated the hypothesis of overpopulation of the capybara in Lago Paranoá, a lake in a large neotropical city, Brasília, Brazil. To do this, we investigated their spatial distribution at the site and estimated the capybara population using a variation of the mark-recapture method and compared it to known population estimates for the species. We found that the capybaras in our study area mainly form small flocks of 1 to 9 animals and occupy almost the entire shore of Lake Paranoá. We estimated the occurrence of 0.30 to 0.52 ind./ha (average = 0.41 ind./ha), demonstrating that the number of capybaras in our region is small when compared to capybara counts in other regions (range 0.075–6.44 ind./ha). Furthermore, we found that although the capybara population fluctuates throughout the year, it appears to be stable, not supporting our initial hypothesis. Urban areas can provide habitat for some species, which may help offset negative effects of losses of unmanaged habitats; however, this raises the possibility of wildlife–human conflicts.