Soil ecosystem services in Amazonian pioneer fronts: searching for socioeconomic, landscape and biodiversity determinants.

In two Amazonian regions of Brazil and Colombia that represent most of the diversity of the pioneer front landscapes, we searched for relationships among socioeconomic environments, landscape composition and structure, biodiversity, and production of goods and ecosystem services. An original sampling protocol was applied to collect fully compatible socioeconomic, landscape, agronomic and ecological datasets allowing rigorous statistical analyses. In each country, 153 farms belonging to three different kinds of land use and practices were characterized on the basis of socioeconomic and landscape variables. Biodiversity, goods and ecosystem services were measured on a selection of 27 (26 in Colombia) farms most representative of the whole diversity in each country. Among the groups chosen for biodiversity survey, plants, earthworms, termites and ants were major ecosystem engineers that play a critical role in the provision of goods (agrosilvipastoral products) and ecosystem services (ES). The investigated ES were climate regulation through carbon sequestration in soil and biomass, soil conservation and water cycle regulation through infiltration, and finally indices of soil quality. Covariations among the different sets of variables assessed by multiple co-inertia analysis were highly significant. Significance of these results are discussed.