An analysis of deforestation patterns in the extractive reserves of Acre, Amazonia from satellite imagery: a landscape ecological approach

Classified multi-temporal Landsat satellite imagery for one of the extractive reserves in Acre, Amazonia was classified into forest and cleared forest patches. Three indices of landscape structure were applied to the classified satellite imagery to characterize the impact of social and economic processes on the development of the forest landscape. The :Lacunarity Index was used to measure landscape homogeneity, the Korcak Patchiness Index to measure the distribution of patches according to their size and the Area-Perimeter Fractal Exponent to measure change in the shape of cleared forest patches. The changing shape, size and spatial frequency of patches in the forest landscape showed that major changes in the forest landscape occurred between 1975-1989. Pre-1975 the region was mainly exploited by family groups who formed an extractive economy based on natural resources. By 1985 the economy had changed, with larger more regular patches indicating a transformed economy based on a settled and well developed farming economy. The techniques are important for measuring the human impact on fragile tropical ecosystems.