Análise da ocorrência do javali (sus scrofa linnaeus, 1758) em unidades de conservação e seus efeitos sobre a comunidade de mamíferos de médio e grande porte

Abstract

The insertion of exotic species into an ecosystem can leave to serious consequences for native biodiversity. The wild boar is an example of invasive alien species that has been introduced in several places of the world and its presence has been linked to the decrease of biodiversity. In Brazil, the species has been recorded for more than two decades and few studies have tried understand the impacts on Brazilian biodiversity and the relationship of this invader with other mammals. Could the boar be impacting the community of medium and large mammals in preserved environments? From this questioning, the two studies presented in this dissertation aimed to evaluate possible impacts of the presence of wild boars in preserved environments. We describe its occurrence in three Conservation Units located in the northeast of Rio Grande do Sul, analyzing if its presence changes the richness and the diversity of other mammals and if its presence is negatively related to particular species (Chapter I and II). We also investigated if their presence cause possible changes in the patterns of activity of the species recorded (Chapter II). Moreover, we evaluated the environmental variables that may favor its occurrence in the studied region (Chapter I). The results obtained in these two studies showed that the wild boars seem to be well adapted to the studied regions, since they used the all conservation units analyzed in a wide and constant way. The environmental variables that seem to favor their occurrence are the amount of forest and the size of the forest fragments. The presence of wild boars does not appear to be influencing the occurrence or altering the richness and diversity of native mammal species. The wild boar also did not appear to significantly change patterns of activity of the most common species, which occurred both in wild boar samples and in those in which this exotic species was not present maintaining its characteristic patterns of activity. Some species of medium-sized mammals to be more sensitive to the presence of boar, but no clear evidence of a negative effect on recorded species has been found. Thus, we may suggest that: the boar may not occur in sufficient abundance in the region to cause impact on the other recorded species; the use by wild boar of the same environments of other mammals may be causing the impression that it does not cause impacts on the richness and diversity of mammals and/or that; access to different resources may be mitigating their impact and allowing the boar to coexist with other species; forest conservation and species diversity may be acting as a xii "protective shield" against the impact of the boar. Although we have not observed negative relationships of the species to the boar, we know that wild boars can affect the biota in varied ways. So, long-term studies are needed and could better elucidate the interactions and effects that boar presence has on native biodiversity.