Ecologia do jacaré de papo amarelo (Caiman latirostris, Daudin 1802) em ambiente urbano no município do Rio de Janeiro

Abstract

The knowledge about of crocodilians' natural history in urban enviroments is scarce and is becoming more necessary due to the urban advancement over the natural habitats in lagunar environments near urban areas in Brazil. Ecological studies in urban areas serve as subsidies to conservation strategies, management motions, and/or adaptations of urban planning. In this study, I analyzed Broad-snouted Caiman's ecology in Rio de Janeiro's urban environent. This study was conducted in a lagoon complex inserted in the city of Rio de Janeiro. The Jacarepaguá Lagoon Complex is located amongst the neighborhoods that most developed in the last ten years, such as: Barra da Tijuca, recreio dos Bandeirantes and all the region of Jacarepaguá. I reseached Broad-snouted Caiman's body growth and its development until sexual maturation age. The process of individual growth is fundamental for all organisms and its respective researches have been a matter of concern to the management and conservation of species. Data for individual growth rate is comprised of recaptures of different animals after known intervals (date of recapture - date of capture). I realized 20 recaptures among 352 captures. The majority of caiman growth studies were accomplished in colder, lower latitude regions, therefore the climatic effects may be an important factor to the development of these animals, demonstrating an adaptive plasticity of the species in responding their development according to environmental factors. After determining caiman's age, I used it to analyze age class distribution, and sexual ratio to understand population dynamics through it's age and sexual structure. It was made a distribution by age group and sex ratio of the individuals of the population and the age stage distribution provided support for a life table for C. latirostris in urban environment. Captured animals totaled 68 (19,3%) juvenile caimans, 180 (51,1%) sub-adults, and 104 (29,6%) adults. Sexual ratio for the captured caimans at the Jacarepaguá Lagoon Complex was 3,3:1 (male:female), where I captured 213 (78,7) males, 65 (21,3%) females, and 90 juvenile caimans whose gender ins not possible to identify. Liquid growth rate of the population resulted in a negative value, which corroborates the alternative hypothesis that the population is diminishing. I concluded that in accordance to sampled data, the population of Broad-snouted caimans in Jacarepaguá Lagoon Complex is not growing, presenting few reproduction and/or survival of juveniles. Due to interaction with the urban environment being increasingly intensified, I realized a socio-environmental research to comprehend what is the relation of human population to the coexistence with caimans in their everyday life in the city of Rio de Janeiro. So, a study was conducted with the intent to identify environmental perceptions and people's (inhabitants and visitors) conceptions of different socio-cultural realities related to the familiarity with caimans in the aforementioned neighborhoods. The approach methodology consisted of the elaboration of open and closed questions. Collected data represented negative-positive conceptions showed by the interviewees about their relation with caimans in Rio's urban environments. throug this study it can be concluded that there is a lack of elaboration proposals of development, environmental education strategies, and better disclosure on ecological notions for the conservation of caimans and their environments. This failure to prepare proposals extends both to the population as to technicians responsible for socio-environmental programs of the city.