Ecologia da paisagem de remanescentes florestais na bacia hidrográfica do ribeirão das pedras - Campinas-SP

Abstract

Due to the fragmentation of forest extracts and land use, often without necessary care to mitigate the impacts resulting from activities performed on it, they are being weakened by a phenomenon such as the effect of edge, which consists of localized changes in the contact areas between the matrix and the disturbed forest fragment. The edge effects cause disruption, which is reflected in changes in the physical environment (abiotic). Those changes consist on the modification of microclimate in the edge zones, wind incidence, humidity and solar radiation, and the biota, and cause direct consequences on the variation of the distribution and individuals density of a specie. In this context, the present study aimed to assess the fragility of the fragments found in Ribeirao das Pedras watershed, Campinas, Brazil. We evaluated the fragment size and the tendency of elongated or circular using GIS techniques, and the existing cartographic base in town. According to the 1962, 1972 and 2006 cartographic database, was observed a decrease in quantity and quality of the fragments. Due to the unplanned urbanization of the municipality, the smaller fragments were deforested area. These, although not ecological capable to sustain higher trophic levels, serve as "stepping stones", contributing to the biological flow. Similarly, the largest fragments were also cleared and its area reduced. In general, the size of the fragments passed to tend to elongate shape, which suggests greater contact between the fragment and the anthropogenic matrix, thereby increasing the vulnerability of the fragments. We highlight the case of the Cerrado remnant found in the extreme northeast of the basin that has a tendency of elongated shape (CI = 0.62) and small area (0.38 ha), thus proving to be very vulnerable to human pressures.