Ecological and socioeconomic aspects of restoring forest in a tropical agricultural landscape, southern Costa Rica

Agricultural landscapes have replaced vast areas of land once under tropical forests. Improving the conservation value of these lands through restoration and reforestation has emerged as a significant focus of global strategies to maintain essential environmental services. This publication presents the results of three studies exploring ecological and socioeconomic aspects of restoration in an agricultural landscape in southern Costa Rica. The first study tested the relative importance of local restoration approach vs. landscape-scale factors to forest recovery by comparing how different restoration tree planting designs, as well as spatial characteristics of the surrounding landscape, influence the arrival of forest seeds. The results showed that areas experimentally planted with native tree seedlings significantly increase the arrival of early-successional tree seeds compared to unplanted areas and that larger planted tree patches or 'islands' (>64m2) receive more seed rain than smaller tree islands. Local tree planting design was also more important to patterns of seed rain than amount of forest in the surrounding landscape. The second study examined how forest fragmentation and habitat degradation influenced causes of post-dispersal seed mortality and the incidence of secondary dispersal (seed caching) by mammals in abandoned pastures, young secondary forests, and small forest fragments. This study showed that scatterhoarding (seed catching in small depots) is a key step in the successful dispersal of some larger-seeded tree species. This dispersal mechanism appears to be disrupted in all but larger forest fragments with potential negative consequences for the persistence of the plant species adapted for secondary dispersal. The results of these two studies suggest that more intensive restoration approaches, such as direct seeding or outplanting seedlings, may be necessary in order to include larger-seeded plant species in early-mid stages of forest succession. Finally, the third study examined how a new Payment for Environmental Services (PES) program for agroforestry on small-scale farms affected tree planting practices and farmer livelihoods. This study suggests that whereas PES significantly increased reforestation practices and overcame initial economic and technical obstacles to agroforestry adoption, investment in short/medium-term support is likely to be necessary for retention of these practices beyond the life of the PES contracts.