Ecologia populacional e alimentar do jacaré-paguá Paleosuchus palpebrosus (Crocodylia: Alligatoridae) em córregos urbanos

Abstract

Urbanization may cause biodiversity declines and even local extinctions, with most severe effects occurring on aquatic fauna, due to pollution, riverbed changes and removal of riparian vegetation. Worldwide, habitat alteration and habitat loss are the main threats to the conservation of crocodilians. In urban areas, these changes may lead, for example, to changes in sex ratios, diet, and age structure of the populations. Paleosuchus palpebrosus is a small crocodilian usually found in oligotrophic streams in several Brazilian ecoregions. In this study, we evaluated the effects of urbanization on some population parameters (sex ratio, size structure, body condition), as well as on the diet of P. palpebrosus from urban streams in Central Brazil. We conducted the study in 45 streams in the urban area of Cuiabá, state of Mato Grosso. We evaluated landscape, water quality, and physical aspects of each stream in order to infer on their level of urbanization. Urbanization did not influence the presence and the diet of P. palpebrosus, but had an effect on density and body condition. This latter was not influenced by diet composition. The population size structure did not differ in the urban area of Cuiabá and in natural environments previously evaluated. The population of P. palpebrosus studied in the urban area of Cuiabá showed negative responses to urbanization, suggesting the possibility of long-term effects.