Flood mitigation ecosystem service in landscapes of Argentina's Pampas: identifying winning and losing farmers.

Ecosystem services are only able to make a contribution to human well-being if they reach the users or beneficiaries. Therefore, it is important to differentiate the potential contributions of ecosystems (ecosystem service supply) from the fraction of the supply that is captured or used. This is even more relevant when the supply and capture of the service occur in different locations. In this case, propagation models are needed to identify who wins and who loses when land-use policies are applied. In this study, we developed an integrated approach for the analysis of supply, propagation and capture patterns of flood-mitigation ecosystem service in rural landscapes and we illustrated how to apply it for the identification of winning and losing farmers under alternative land-use scenarios. The proposed approach allowed us to differentiate farms according to their flood mitigation capacity and to estimate how that capacity could be affected by changes in land use. It also highlights the importance of considering the propagation and capture of ecosystem services in evaluations. Reliable methodological developments are scarce. Therefore, flexible tools such as this proposal are necessary to fit the available information and the context to be analyzed.

Direct effects of habitat area on interaction diversity in pollination webs.

Island biogeography theory predicts that species richness increases with habitat area and declines with isolation. We expand this framework to address changes in the number of links and species in pollination webs from 12 isolated hills, ranging in area from tens to thousands of hectares, immersed in the agriculture matrix of the Argentine Pampas. We also studied whether total interaction frequency is partitioned more evenly among individual links in richer webs. Our results reveal a direct effect of area on the number of links and species present in each pollination web. However, link richness increased twofold faster than species richness with area. These area effects were not confounded by sampling effort or correlated incidence of exotic species, despite widespread habitat disturbance. Habitat proximity, an inverse measure of isolation, had a marginally significant influence on link but not on species richness. Increased link number was associated with decreasing dominance by any particular interaction and increasing interaction evenness. Despite the strong area effect, a rich pollination web sampled from a small, protected sierra suggests that simple conservation measures, such as reduced grazing and fire suppression, may effectively preserve much local interaction diversity.