Linking Spatial Pattern and Ecological Responses in Human-Modified Landscapes: The Effects of Deforestation and Forest Fragmentation on Biodiversity



Studies of forest loss and fragmentation provide clear examples of the linkages between ecological pattern and process. Reductions in forest area lead to higher within-patch extinction rates, the eventual loss of area-sensitive species, and declines in species richness and diversity. Forest loss also results in increased isolation of remnants, lower among-patch immigration rates, and less ‘rescue’ from surrounding populations. Specific responses, however, are sometimes counterintuitive because they depend on life-history tradeoffs that influence population dynamics and species co-existence in heterogeneous landscapes, not just forest remnants. Thus, while fragmentation generally favours r-selected, generalist strategies, such as high dispersal and a wide niche breadth, ecological outcomes may be confounded by species-specific responses to conditions in the human-dominated matrix and the ways in which forest edges shape cross-landscape movements. Given that pressures on global forestlands continue to intensify due to growing population sizes, economic pressures, and needs for space and resources, successfully maintaining or restoring species will necessitate a combination of short- and long-term actions that address both habitat protection and restoration. Doing so will require an interdisciplinary approach that gives adequate attention to the manners by which forest loss and fragmentation affect population dynamics through changes in forest area, isolation, habitat quality, matrix properties, and edge effects as well as the synergistic interactions of fragmentation with climate change, human-altered disturbance regimes, species interactions and other drivers of species population declines.