Countryside Biogeography of Neotropical Mammals: Conservation Opportunities in Agricultural Landscapes of Costa Rica

Abstract: The future of mammalian diversity in the tropics depends largely on the conservation value of human‐dominated lands. We investigated the distribution of non‐flying mammals in five habitats of southern Costa Rica: relatively extensive forest (227 ha), coffee plantation, pasture, coffee with adjacent forest remnant (<35 ha), and pasture with adjacent forest remnant (<35 ha). Of the 26 native species recorded in our study plots, 9 (35%) were restricted to forest habitat, 14 (54%) occurred in both forest and agricultural habitats, and 3 (11%) were found only in agricultural habitats. Species richness and composition varied significantly with habitat type but not with distance from the extensive forest. Interestingly, small forest remnants (<35 ha) contiguous with coffee plantations did not differ from more extensive forest in species richness and were richer than other agricultural habitat types. Small remnants contiguous with pasture were species‐poor. When clearing started, the study region likely supported about 60 species. Since then, at least 6 species (10%), one family (4%), and one order (11%) have gone extinct locally. The species that disappeared were the largest in their families and included carnivorous (e.g., jaguar [Panthera onca]), herbivorous (e.g., Baird's tapir , [Tapirus bairdii]), and arboreal (e.g., mantled howler monkey [Alouatta palliata]) species. Although there is no substitute for native forest habitat, the majority of native, nonflying mammal species use countryside habitats. The populations of many persist even >5 km from relatively extensive forest, at least over the 40 years since forest clearance. Moreover, if hunting ceased, we expect that at least one of the locally extinct species could be reestablished in the existing landscape. Thus, there is an important opportunity to maintain and restore the diversity, abundance, and ecosystem roles of mammals in at least some human‐dominated regions of the Neotropics.