With a population of 391 million (2010) and growing at a rate of 1.2% per year (Population Reference Bureau 2010), South America is yet another variation on the theme of rapid population growth and economic expansion. The situation in South America is one of shifting priorities in terms of land use. Clearing of tropical forests in order to create pasture for cattle has long been in practice, but mechanized agriculture gained a foothold in the Amazon in the early 21st century. This trend has been fueled by international interest, particularly soybean and biofuels industries. Clearing forests to make way for mechanized agriculture is now second to clearing for pasture in terms of land use change in South America (Morton et al. 2006).