Community Counting Carnivores: Discrepancies between volunteer and DNR winter gray wolf counts in Wisconsin 2003-2011

Large carnivores are threatened globally, with most extant taxa having suffered significant historical range contractions. Due to this imperiled status, as well as increased scientific interest in top-down ecological processes, ecologists and conservationists have dedicated renewed efforts towards large carnivore preservation and management. As part of these efforts, reliable and transparent population monitoring is critical both to evaluating population dynamics as well as to detecting policy and management effects on large carnivore populations. Therefore, it is imperative to evaluate how methodological changes to monitoring regimes may affect the bias and uncertainty of estimates, especially with cryptic and politically contentious taxa like large carnivores. We describe methodological changes in Wisconsin gray wolf (Canis lupus) censusing techniques by the Wisconsin Department of Natural Resources (DNR), paying particular attention to a citizen science program where volunteers conducted winter wolf track surveys separately from DNR trackers. We hypothesize how changes to volunteer training and participation in winter wolf counts may have resulted in several methodologically distinct time series of wolf population estimates. To investigate this hypothesis, we use a Bayesian mixed effects model to analyze how volunteer and DNR trackers counted wolves during a relatively methodologically consistent period from 2003 to 2011 and find that volunteers counted 83% (95% CI: [74%-92%]) as many wolves as DNR trackers. Therefore, we conclude that changes in relative volunteer involvement before and after that period must necessarily affect the bias and precision of wolf population estimates. We hypothesize possible reasons for this discrepancy between volunteer and DNR trackers, including differences in tracking aptitude, potential biases among trackers, and differences in survey timing. We also simulate volunteer and DNR wolf counts as if both tracker types had surveyed all blocks across all years to compare our reproducible wolf count uncertainties to DNR-reported uncertainties. We end with recommendations for more transparent and reproducible wolf counting by the DNR and broader recommendations for ecological citizen science initiatives.