Rapid agriculture developments in the Neotropics have caused substantial decline in the biodiversity of the region primarily through habitat loss and degradation. However, the traditional framework of establishing reserves around forested areas is insufficient to conserve biodiversity in light of the rate of agriculture expansion. Instead, attention should be placed on managing for biodiversity-friendly production. To assess how agriculture practices affect local biodiversity, we surveyed terrestrial small mammal communities in two tropical coffee farms under differing management regimes. The first farm is a shaded organic system resembling traditional polycultures with multiple native shade trees forming a dense overstory. In comparison, the second farm is a sparsely shaded monoculture with highly pruned vegetation. Small mammals were chosen as study subjects due to their importance as seed dispersers and potential sensitivity to landscape changes. Live-trapping at eight different sites provided comparisons of diversity between the two farms. The second part of the study aims to address the question of what microhabitat characteristics affect small mammal distribution. Ten microhabitat variables were recorded at each plot and regressed with diversity data to identify underlying patterns of diversity and the environment.
Results/Conclusions
Species richness across farms was identical, constituting of members from the order Rodentia. Surprisingly abundance was significantly higher in the more intensified farm, although species evenness was higher in the organic farm. The only forest specialist in the system – Heteromys desmarestianus – was found in low numbers in either site, but constituted over 80% of the individuals captured in the forest remnant between the farms. Landscape level variables such as the distance to a ravine demonstrated strong negative correlation with species diversity. This suggests the importance of ravines as pockets of refuge within human-modified landscape. On a local level, microhabitat factors such as coffee density and herbaceous ground cover were found to have significant positive impacts on overall species diversity. In conclusion, while many small rodents are tolerant of disturbance, forest patches remain as primary reservoirs for forest specialists. Likewise, certain landscape and vegetation characteristics are crucial for small rodents and cannot be overlooked in management plans.