We propose studies in two theme areas of LBA Ecology: land use and land cover change (LULC), and Carbon Storage and Exchange. This will involve examining the human and biophysical dimensions of LULC in the Ecuadorian Amazon associated with high rates of spontaneous colonization (land clearing) by agricultural settlers migrating into the region since the early 1970s. A satellite time series from the 1970s through 1998, along with GIS thematic coverage's of biophysical gradients and geographical accessibility, will be linked to data collected on the ground from a unique scientific sample of georeferenced farm household plots and nearby communities. Data will be collected from the latter in 1998-99 on the same settler plots surveyed in 1990 to measure LULC over time in detail, and to relate it to population and socioeconomic characteristics of settler households. Image processing to characterize LULC and spatial analyses of landscape structure will be used to assess the rate and nature of LULC and to model the effects of LULC, secondary plant succession, and land fragmentation on carbon budgets and assimilation rates for landscape strata and the study area as a whole. Statistical models will be used to estimate the demographic, socioeconomic, biophysical, and geographic determinants of LULC at the farm and community levels. Agricultural extensification and intensification will be documented at the three spatial scales of the farm plot, the sector or community of which it is a part, and the region. The project will be carried out in an area which is in the Amazon headwaters, one characterized by extraordinary biodiversity, undergoing more rapid colonization and deforestation than elsewhere in the Western Amazon due to its being opened following the discovery of large oil deposits. A scientifically representative sample of 480 household settler plots interviewed in 1990 will be re-visited in 1998 to provide a unique, representative assessment of changes in LULC over time, including land extensification, land intensification (and sustainability of agricultural technology), land abandonment, and secondary succession, with implications for the carbon budget. Lessons will be learned about the process of LULC and its implications for carbon budgets as well as policies to promote to improve sustainability of methods and forest preservation.