Marcus Atkins

Thompson Rivers University
Periodic assessments on the status of wildlife populations rely on the best available science, however, long-term datasets that utilize historical, comparative data are limited. Additionally, the ways that various land management regimes, including parks and protected areas, impact species are poorly understood. Robust historical comparisons allow for the quantification of long-term impacts and can help prevent the phenomenon of shifting baselines. This study represents the first comparison of long-term population changes of Western Rattlesnakes (Crotalus o. oreganus) in Canada.  Temporal comparisons of the population are being conducted through a rigorous mark-recapture to compare and assess baseline demographic data with a detailed historical dataset from the early 1980s. Since this data was collected, the study site has been divided into a ‘natural experiment’ of contrasting land-use patterns; half of the area within the boundaries of a provincial park and half within an active cattle ranch. Spatial comparisons between sites aim to determine how long-term, divergent land management regimes influence populations and whether provincial park lands offer population scale protection. This project is still in preliminary stages, with one full field season of data and limited results thus far. We have observed, among adult males, a significant disparity (P=0.034) in average SVL, and near-significant disparity (P=0.055) in average weight with longer and heavier snakes skewed towards ranchlands. Continuing research aims to bolster mark-recapture at den sites, use radio telemetry to improve movement, feeding ecology, and reproductive data, and quantify the impacts of differential land use on habitat structure and demography.