Working with experts to quantify changes in the abundance of furbearers following rapid and large-scale forest harvesting

Across western Canada, furbearers are being subjected to the cumulative impacts of industrial development. This region has witnessed unprecedented levels of anthropogenic change, primarily in the form of increased forest harvesting. We used trapping records to investigate the relationship between habitat and the abundance of Canada lynx (Lynx canadensis) and American marten (Martes americana). We applied expert-based habitat models to ten reference landscapes (i.e., traplines) in two distinct study areas to serve as measures of habitat change from 1990 to 2013. We elicited fur harvest records from trapper experts and then used negative binomial count models to relate capture success to habitat availability and quality. We controlled for factors that were hypothesized to influence capture success, including effort and weather conditions, allowing us to model the effects of habitat availability and quality on population abundance. Expert-based habitat models revealed that the area and quality of habitat declined significantly as a result of increased forest harvesting. The top-ranked count models identified combinations of habitat availability and quality, trapping effort, and trapline area as factors positively influencing the capture success of lynx and marten. Results suggested that the reduction in high-quality habitat negatively affected the abundance of marten in the study area. Methods and findings also illustrated the utility of harvest records for investigating population abundance of furbearer species. A precise measure of trapping effort, however, is necessary to relate environmental covariates, including habitat, to harvest at the scale of individual traplines.