Caracterização da comunidade de mamíferos de médio e grande porte em paisagem agrícola fragmentada / Characterization of the mid and large bodied mammal community in a fragmented agricultural landscape

AUTOR(ES)
FONTE

IBICT

DATA DE PUBLICAÇÃO

22/06/2012

RESUMO

Agricultural expansion is a major cause of habitat fragmentation, leading to a reduction and isolation of natural areas. It is therefore important to understand the role of agricultural landscape structure and dynamics in maintaining local biodiversity. We aimed to describe how the structure and dynamics of an agricultural landscape influenced the community of mid and large bodied mammals in the south of Brazil. From May to October 2010 we studied the mammal community in five 16 km2 landscape units located within the Corumbatai river basin, São Paulo. Landscape units contained a matrix of predominantly pasture (n = 2) and cane sugar (n = 3). We used track surveys along 15 transects (200m each) to sample the mammal community along river banks. To calculate indices of habitat structure and dynamics we generated buffers (250, 500, 1000 and 2000 m radius) around each of the transects. Within each of these distance buffers we calculated habitat structure indices (percentage of land use, drainage density, road density and proximity of fragments) and indices of habitat dynamics (annual rate of change and profile of the forest change curve) for five years (1962, 1978, 1995, 2000 and 2008). The relationship between landscape indices and species richness was analyzed through a PCA (Principal Component Analysis) and associated Biplot. Subsequently, multiple linear regression was performed to analyze the influence of landscape structure and dynamics on species richness and frequency of records. We recorded 19 species, 17 in cane sugar units and 13 in pasture units. The community of mid and large bodied mammals present in the habitat matrices of the Corumbataí river basin was represented mostly by generalist species tolerant of environmental changes. The most frequently recorded species was Procyon cancrivorus, a habit generalist. The PCA Biplot showed that the 1000m buffer was the one that best distinguished the sampling sites in relation to the sugar cane and pasture matrices. Species richness was positively related with the percentage of forested areas and drainage density. In contrast, richness was negatively related with the percentage of pasture. The richness and frequency of records showed no statistically significant difference between the two matrix types and there was no significant relationship between landscape indices and the dependent variables. The similarity between the species composition of the sampled communities in the matrices was 57%. Understanding the relationships between the composition of this community and the landscape structure and dynamics requires more efforts, as the survey method used in this study, and the spatiotemporal scale, do not permit the description of these relationships.

ASSUNTO(S)

agricultural ecosystem animal populations biological conservation conservação biológica ecologia da paisagem ecossistemas agrícolas environmental protection landscape ecology mamíferos mammals populações animais proteção ambiental

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