Liberação ecológica em lagartos em uma área de mata atlântica e brejo de altitude do nordeste brasileiro

Abstract

The assemblages of lizards from an area of “Brejo de Altitude Nordestino” (isolated area) and a remnant area of Atlantic Coastal Forest (non-isolated area) were compared in order to test the ecological release hypothesis, which predicts that in case of ecological release, the amplitude of niche and abundance of species should be higher in the isolated area when compared to the non-isolated area. The average of the dietary niche breadth of the lizards was calculated using numerical and volumetric values of the diet of 148 individuals from 10 different species for the individual and grouped stomachs. The abundance data were estimated using the mean number of lizards collected in the pitfall traps in 4 expeditions of 5 days, totaling 20 days of sampling per area. In order to verify if the phenomenon of ecological release occurs for the assemblages of lizards, Generalized Linear Mixed Models were used, which allow the insertion of random variables, correcting the calculation of the degrees of freedom of the sample. As expected, species richness was higher in the non-isolated area when compared to the isolated area, however, the abundance of lizards was not higher in the isolated area, indicating that it is not increasing in compensation for the lower species richness in the isolated area, as is expected in the hypothesis of density compensation. Also, no significant difference was found in the values of the dietary niche breath between the areas, indicating that the species are not expanding their niche. Thus, no evidence of ecological release was found in the study, suggesting that the assemblage studied has a fairly conserved ecology and that historical factors may better explain dietary patterns for this assemblage than ecological factors.