Not all ponds are created equal: long-term beaver (Castor canadensis) lodge occupancy in a heterogeneous landscape

Abstract

Modeling habitat selection often represents single spatial scales and short time periods. However, for species that dramatically modify environments upon initial colonization, non-linear interactions change original habitat to one where habitat selection is confounded by subsequent modifications by the organism itself. The ability of beavers (Castor canadensis Kuhl, 1820) to dramatically alter habitat components over time makes them a model species for examining habitat selection spatially and temporally. This study identified habitat features selected by a relatively long-lived, colonial species, and how selection influenced site occupancy over varying spatial scales. Remote sensing and field data provided spatial and temporal coverage of four measures of occupancy. Models of occupancy over an 11-year period, combined with environmental variables, identified features influencing occupancy, abandonment, and recolonization at 30, 50, and 100 m scales. Unlike many studies, % deciduous was a poor predictor of occupancy. Instead, pond area, % grassland, distance to a pond that was active at least once, and standard deviation (SD) of slope were important variables. SD of slope was the only variable not influenced by beavers. Examining species–habitat relationships over broader spatial and temporal scales, particularly for ecosystem engineers, enhances understanding of non-linear effects and how they influence perceptions of habitat selection.