Fragmentation research has traditionally focused on how patch-level attributes such as patch area and isolation affect communities, while ignoring the landscape context.  The nature of land-cover between primary habitat patches (termed the “matrix”), however, may ultimately drive colonization-extinction rates in fragmented landscapes more than by patch area or isolation alone. Matrix areas may potentially impact the movement of individuals among patches, the acquisition of resources, or the type and magnitude of edge effects.  Based on presence/absence data across three years (2005-07) in almost 100 forest patches embedded in four matrix habitat types (agriculture, bauxite mining, peri-urban development, and forest), we determined the extent to which the landscape matrix mediates patterns of occupancy in neotropical bird populations in central Jamaica.  Our analyses focused on insectivorous birds, because they are a guild disproportionately affected by forest fragmentation worldwide.  We employed multiseason patch-occupancy models to test a priori hypotheses about the relative influence of patch area, patch isolation, habitat structure, and matrix context on local colonization and local extinction dynamics.  This approach is novel in isolating effects of matrix composition by controlling for the spatial pattern of primary habitat (i.e., area and distance of forest patches) in fragmented landscapes, while incorporating species detection probabilities and testing alternative hypotheses via multi-model selection and model averaging. 

Results/Conclusions

Our results indicate that for the majority of insectivorous birds in Jamaica, the most important factors mediating local extinction probabilities were within-patch habitat structure mediated by matrix context, over and above patch-area.  Local extinction tended to drive differential population dynamics, over and above local colonization.  The effects of spatial isolation of patches on local colonization probabilities tended to be contingent upon matrix conditions, however, the effects of patch isolation and matrix context were less consistent across species.  Overall results suggest that avian communities were more dynamic and less stable in landscapes fragmented by bauxite mining and to a lesser extent peri-urban development.  These findings lend crucial empirical support that community stability within forest remnants depends greatly upon the landscape context within fragmented tropical systems.