Geographic gradients of deforestation and mammalian communities in a fragmented, temperate rain forest landscape


Mark V. Lomolino, Department of Environmental and Forest Biology, SUNY College of Environmental Science and Forestry, Syracuse, NY 13210, USA. E-mail:


Aim  We studied the temporal and spatial patterns in deforestation and community structure of mammals in a fragmented old-growth, temperate rain forest to test the hypothesis that anthropogenic habitat conversion advances in a nonrandom manner across native landscapes, and that its effects on ecological communities are both persistent and predictable.

Location  The location is the Hood Canal district of Olympic National Forest, Washington, USA.

Results  Deforestation followed the apparently general pattern observed for deforestation of tropical rain forests and other native landscapes, advancing first along low and relatively level valleys, then to areas at higher elevations and along steeper slopes, and eventually to sites more distant from those of initial land conversion and transportation centres. Mammal surveys within this area indicated that this nonrandom advance of deforestation has created relatively steep geographical and topographic gradients in both local and landscape-level factors and, ultimately, in the structure of mammalian communities.

Conclusion  The close and likely causal relationship between anthropogenic habitat loss and the ecological dynamics of mammalian communities and dependent species (e.g. spotted owls) indicates that our abilities to understand and eventually reduce the current extinction crisis may rely heavily on our understanding of, and abilities to modify, the manner in which we expand across and transform native landscapes.