Resource use by marten at fine spatial extents

Abstract

Martens (Martes spp.) occupy areas with complex forest structure that can exhibit patchy distribution, particularly in managed forest landscapes. These structures (e.g., downed wood) are often difficult to reliably sample so more easily acquired surrogates may better describe marten habitat. Recent advances in global positioning system (GPS) collars combined with integrated (i.e., imagery with geospatial modeling), resolute, remotely sensed maps offer a potentially efficient means of understanding marten space use. We placed GPS collars on 13 American marten (M. americana), attempted to acquire a locational fix every 15 min, and calculated adaptive kernel home ranges from successful locations. We modeled probability of marten use as a function of covariates derived from remotely sensed data that included proportion of vegetation cover types, and distances to maintained roads and hydrographic features at 2.5, 4.5, and 7.1 ha extents. Average cover type values varied minimally across spatial extents we evaluated, indicating fine-scale homogenization. Amount of tall (> 10 m) deciduous forest, tall and short conifer forests, and riparian forests had positive effects on marten use, whereas distance to maintained roads had a weak negative effect. Broad riparian areas (e.g., scrub–shrub swamps that occur in broad topographic depressions), not necessarily associated with mapped hydrographic lines, were heavily used by marten. We found that core use areas for marten could reliably be predicted from 30 m remotely sensed maps summarized at relatively small extents (2.4–7.1 ha).