Landscape dynamics result from forestry and farming practices, both of which are expected to have diverse impacts on ecosystem services (ES). In this study, we investigated this general statement for regulating and supporting services via an assessment of ecosystem functions: climate regulation via carbon sequestration in soil and plant biomass, water cycle and soil erosion regulation via water infiltration in soil, and support for primary production via soil chemical quality and water storage. We tested the hypothesis that patterns of land-cover composition and structure significantly alter ES metrics at two different scales. We surveyed 54 farms in two Amazonian regions of Brazil and Colombia and assessed land-cover composition and structure from remote sensing data (farm scale) from 1990 to 2007. Simple and well-established methods were used to characterize soil and vegetation from five points in each farm (plot scale). Most ES metrics were significantly correlated with land-use (plot scale) and land-cover (farm scale) classifications; however, spatial variability in inherent soil properties, alone or in interaction with land-use or land-cover changes, contributed greatly to variability in ES metrics. Carbon stock in above-ground plant biomass and water infiltration rate decreased from forest to pasture land covers, whereas soil chemical quality and plant-available water storage capacity increased. Land-cover classifications based on structure metrics explained significantly less ES metric variation than those based on composition metrics. Land-cover composition dynamics explained 45 % (P < 0.001) of ES metric variance, 15 % by itself and 30 % in interaction with inherent soil properties. This study describes how ES evolve with landscape changes, specifying the contribution of spatial variability in the physical environment and highlighting trade-offs and synergies among ES. (Résumé d'auteur

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International audienceIn Argentina, the recent expansion of agriculture has turned into an extreme process almost completely dominated by soybean. The magnitude and speed of soybean expansion are believed to be the main drivers behind social, organizational and economic changes, including the displacement of small-scale producers out of agriculture. Under these transformations, land leasing is a critical management practice and constitutes a link among agricultural actors. This study analyzes changes in land tenancy patterns considering the recent agriculturization process but also older drivers of change. Our results indicate that the expansion of agriculture affects small-and large-scale farms differently, as land renting practices and productive orientation show clear differences by size. In the land leasing market, local producers are the main tenants while sowing pools rent about one quarter of the leased land. The competition for leasing farmland appears to operate within farm sizes. Small-and medium-scale producers compete among them for land, while large-scale local producers compete with sowing pools for the larger plots. Sowing pools do not appear to be the main drivers of land tenancy changes as they are no more relevant than local actors in the land leasing market. However, results suggest that small-scale landowners renting out their land for several years are the ones with higher probabilities of selling their lands. This segment of producers appears to be the one most negatively affected by soybeanization