Structural complexity characterizes fine‐scale forest conditions used by Pacific martens

Abstract

When wildlife species exhibit unexpected associations with vegetation, replication of studies in different locales can illuminate whether patterns of use are consistent or divergent. Our objective was to describe fine-scale forest conditions used by Pacific martens (Martes caurina) at 2 study sites in northern California that differed in forest composition and past timber harvest. We identified denning and resting locations of radio-marked martens and sampled structure-and plot-level vegetation using standardized forest inventory methods between 2009-2021. Woody structures used by martens were significantly larger than randomly available structures across types (e.g., live tree, snag, log) and at both study sites. Den and rest structures occurred in areas characterized by higher numbers of logs and snags, lower numbers of live trees and stumps, larger diameter live trees and logs, and

Functional responses in American marten habitat selection indicate cumulative effects of progressive habitat change

“…The two species are extremely similar in their life histories and habitat selection behaviors, displaying a strong association with structural conditions typically found in mature forest. High canopy cover and basal area, an abundance of large trees and snags, large amounts of coarse woody debris, and vertical forest complexity have all been positively associated with marten habitat selection (Delheimer et al, 2023; Fuller & Harrison, 2005; Hodgman et al, 1994; Moriarty et al, 2016; Payer & Harrison, 1999; Thompson, 1994; Tweedy et al, 2019) as these structural forest attributes provide marten with escape cover from predators, an abundance of prey and high predation success rates, and ample resting and denning sites. Young (<6 m mean tree height) regenerating clearcuts and heavily thinned forests lack the structural complexity of mature forest, and research indicates such habitat types are consistently avoided by marten (Buskirk & Powell, 1994; Cushman et al, 2011; Moriarty et al, 2016; Payer & Harrison, 1999).…”