Gatos domésticos em ambiente insular de Mata Atlântica: potenciais impactos sobre mamíferos silvestres e a castração como estratégia para conservação

Abstract

Anthropic changes in the landscape provide potential threats to several mammal species. The introduction of domestic species is a strong pressure, by either the predation, competition, or placement of domestic diseases to wild lives. The domestic cat has biological and behavioral characteristics that allow to it a great adaptability to natural areas, promoting thus the exploitation and occupation of these environments, increasing risks to native species. Because of this, its action is one of the main reasons for the loss of species, especially on islands. It is therefore imperative the need to verify these potential threats and the evaluation of strategies aimed to mitigate them. In this study, the interference of female presence was observed as an important factor for determining the dimensions of the males home range. It has been found the predation on all kinds of small non-flying mammals, sampled on collection campaigns in an Islander Atlantic Environmental Protection Area. However, it was possible to detect opposite values expected for wealth, abundance and species diversity among different areas, considering the presence or absence and the density of these felines. It was also found that for semi-domiciled cats, the availability of preys was not decisive for the consumption of these species, which reinforces its generalist and opportunistic behavior of predation. In addition to this, there was a superimposition among four species of Neotropical felines in relation to areas used by domestic cats living in this Protection Area. In regards to the strategies to mitigate the impacts by the presence of cats, the intervention through castration of males significantly reduces both the home range (75.89%), and the pattern of activity (73.59%) of these cats under semi-domiciled conditions. However, even with the reduction of this activity area after the castration procedure, it was expected the same effect for the prey consumption of, but it was found that castration did not interfere on the consumption nor on the estimates of small non-flying mammals, sampled in natural areas where there is sympathy with cats. The presence of exotic species of small mammals with close association with anthropic environments, registered only in fecal samples analyzed both in the previous period and the post-castration period, and the small variation in the number of preys consumed indicate that this predation possibly occurs in the vicinity of the properties where these cats reside. The results indicate that, although it should be encouraged in order to avoid a disorderly growth of the cat population in these areas, castration should not be the only strategy used to minimize possible impacts caused by the presence of these felines in natural areas.