Uso do habitat por três espécies simpátricas de crocodilianos (Crocodylia, Alligatoridae) na Reserva Extrativista do Rio Ouro Preto, Amazônia

Abstract

The habitat use by sympatric species depends of the different utilization of specific habitat according to the behavior and preference of each species. For caimans, hydrodynamic characteristics, temperature variation, and the landscape around aquatic ecosystems can influence the difference in spatial distribution. In addition, particular characteristics of each species, such as body size and life stage are related to the use of specific habitats. In this context, we investigate how habitat characteristics influence the spatial distribution of three species of caiman: Caiman crocodilus, Melanosuchus niger and Paleosuchus palpebrosus, in the western Amazon, and whether there is a difference in the spatial distribution of different life stages of these species. In addition, we analyzed factors that affect the detectability of crocodilians and propose an index for monitoring the density of crocodilians based on environmental characteristics. For this, we related hydrodynamic characteristics of the water body (lotic and lentic), the landscape (forest, grasses and sandbar), temperature variation, period and water level, with the densities of the species and their size classes. We found that species respond differently to variations in the environment, which are being determined by different behaviors and morphologies between species. We also observed intraspecific differences that may be related to the type of aquatic environment. In addition, ours findings about P. palpebrosus nest ecology and the biometry of captured animals, emphasize the importance of knowledge of basic information about species, such as nesting areas, hatching size, biometrics and species coexistence. This information is important to support short-term and long-term conservation and management of caiman in Conservation Units.