Ecosystem service trade-offs and land use among smallholder farmers in eastern Paraguay

The trade-off between economically critical provisioning services and environmentally sustaining supporting services often seems absolute. Yet, when land use is inefficient, managers may be able to increase provision of both economically and ecologically sustaining services. To explore such sustainable "win-win" outcomes, I present a model of predicted trade-offs of provisioning and supporting services on smallholder farms in eastern Paraguay. The spatially implicit model simulates smallholder parcels as mosaics of subsistence agriculture, cattle pasture, eucalyptus plantations, and/or natural forest cover, and predicts provisioning and supporting service supply depending on the relative abundance of each land-use type per parcel. I represent provisioning services as the annual, per-ha proportion of a smallholder family's subsistence needs met by agriculture and forestry. I represent multidimensional supporting services as a composite index of forest bird biodiversity, soil organic carbon content, and aboveground annual net primary productivity (NPP) relative to what would be expected in a stand of high-quality Atlantic Forest. I use this model first to predict ecosystem-service supply for 38 actual smallholder parcels in rural eastern Paraguay, and then to generate an efficiency frontier that illustrates the optimal trade-offs between provisioning and supporting services that are biophysically possible for the system. Comparison of the empirical findings and the efficiency frontier indicates that current land use is inefficient relative to the biophysical optimum. All smallholder parcels included in the study but one lie far from the modeled efficiency frontier, indicating that for a given level of agricultural and forestry production, supporting services are not optimally conserved. If parcel owners were able to overcome constraints to sustainability by, for example, transitioning from cattle ranching to agroforestry production, they could protect high levels (often upward of 90%) of the supporting ecosystem services provided by natural forest without sacrificing economically valuable provisioning services. Pathways to such sustainable outcomes are discussed.