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Quantifying the effects of spatial configuration on Newfoundland marten (Martes americana atrata) habitat quality.
ADAIR, WILLIAM1, BISSONETTE, JOHN1, 1
ABSTRACT- Ecologists have long recognized that for many wildlife species, habitat quality depends on both the quantity of resources and their spatial configuration. While wildlife habitat models often address resource dispersion, very few models have attempted a spatially explicit approach to assessing habitat quality. Because Newfoundland marten favor old-growth forests and avoid openings, they provide an ideal case study for examining the costs and benefits associated with spatially explicit habitat models. We developed a suite of models that assess habitat quality by linking den sites to foraging patches, thereby mimicking the marten's habitat selection process. To quantify the effects of spatial configuration on habitat quality, we compared models that assume that marten travel freely across the landscape (no restrictions) with models that assume that marten avoid openings up to 50 meters and 100 meters wide. Not surprisingly, movement barriers had an adverse effect on habitat quality and this effect depended on the proportional abundance of these barriers. However, this effect was nonlinear and imperfectly explained by conventional landscape configuration metrics. We conclude that for species that encounter movement barriers, accurate habitat assessment may depend on models that quantify resource configuration directly, and that indirect approaches may be inadequate.
KEY WORDS: Martes americana, habitat models, spatial configuration