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Protected areas are important in species conservation, but high rates of human-caused mortality outside their borders and increasing popularity for recreation can negatively affect wildlife populations. We quantified wolverine (Gulo gulo) population trends from 2011 to 2020 in > 14,000 km2 protected and non-protected habitat in southwestern Canada. We conducted wolverine and multi-species surveys using non-invasive DNA and remote camera-based methods. We developed Bayesian integrated models combining spatial capture-recapture data of marked and unmarked individuals with occupancy data. Wolverine density and occupancy declined by 39%, with an annual population growth rate of 0.925. Density within protected areas was 3 times higher than outside and declined between 2011 (3.6 wolverines/1000 km2) and 2020 (2.1 wolverines/1000 km2). Wolverine density and detection probability increased with snow cover and decreased near development. Detection probability also decreased with human recreational activity. The annual harvest rate of ≥ 13% was above the maximum sustainable rate. We conclude that humans negatively affected the population through direct mortality, sub-lethal effects and habitat impacts. Our study exemplifies the need to monitor population trends for species at risk—within and between protected areas—as steep declines can occur unnoticed if key conservation concerns are not identified and addressed.

Global populations of wildlife are affected by human activity, land cover change, and climate change. Long-term monitoring programs across large spatial scales are required to understand how these and other factors affect wildlife populations. Occupancy models are frequently used to monitor changes in species distribution while accounting for imperfect detection. Occupancy surveys can be expensive because they typically require multiple surveys to estimate the probability of detection. Time-to-detection models provide a promising approach for estimating occupancy because they require just one visit; however, few studies have tested or applied these models to wildlife data. We ran a simulation study to assess biases of time-to-event occupancy models for standardized avian point-count surveys and then applied the models to 10 yr of data. Time to first detection occupancy models had minimal bias and almost nominal coverage for species with a mean time to first detection <8 min on surveys with 10 min of sampling. Biases and root mean squared error increased with increasing time to first detection. We applied a single species, multiyear occupancy model to 34,665 detections of 77 landbird species collected across 500 km of latitude in five protected areas along the Rocky Mountains. Models from 64 species converged and had mean times to first detection <8 min. Average time to first detections was 3.2 min, which reflected a cumulative probability of detection of 0.96. Occupancy rates increased, decreased, and remained unchanged for 53%, 9%, and 38% of species, respectively. Overall, occupancy rates increased in 2015 and 2016 for short-and long-distance migrants and decreased slightly for winter residents. Average decadal temperature and precipitation were important predictors for almost half of the species, while annual changes in spring temperature and precipitation affected 23% of species. Our studies demonstrate that time to first event occupancy models provide an efficient method for monitoring changes in distribution so long as encounter rates are much shorter than the survey duration. Our stable to increasing trends and strong responses to spring temperature and precipitation highlight the value of long-term monitoring for understanding how changing climatic conditions affect wildlife.

Railways are a major source of direct mortality for many populations of large mammals, but they have been less studied or mitigated than roads. We evaluated temporal and spatial factors affecting mortality risk using 646 railway mortality incidents for 11 mammal species collected over 24 years throughout Banff and Yoho National Parks, Canada. We divided species into three guilds (bears, other carnivores, and ungulates), compared site attributes of topography, land cover, and train operation between mortality and paired random locations at four spatial scales, and described temporal patterns or mortality. Mortality risk increased across multiple guilds and spatial scales with maximum train speed and higher track curvature, both suggesting problems with train detection, and in areas with high proximity to and amount of water, both suggesting limitations to animal movement. Mortality risk was also correlated, but more varied among guilds and spatial scales, with shrub cover, topographic complexity, and proximity to sidings and roads. Seasonally, mortality rates were highest in winter for ungulates and other carnivores, and in late spring for bears, respectively. Our results suggest that effective mitigation could address train speed or detectability by wildlife, especially at sites with high track curvature that are near water or attractive habitat.

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