Characterizing land-use change over space and time: applying principal components analysis in the Brazilian Legal Amazon

We apply a principal component analysis to characterize the dimensions of spatio-temporal change in agriculture within the Brazilian Legal Amazon for the period 1996–2006. Around 80% of spatio-temporal variation across a broad set of descriptors could be explained by four trajectories well observed in the region: large-scale ranching, inactive forested property, small-scale farming, and mechanized agriculture. Spatial clustering based on these trajectories reveals a shift in the characteristics of the agricultural frontier, and provides quantitative method for distinguishing functional sub-regions previously suggested in the literature. Our analysis suggests a marked growth in agriculture over the decade between 1996 and 2006, with agricultural development encroaching toward the interior of the Brazilian Amazon not only from the south and southeast, but also from the west.