Pelt color serves many functions from signaling to crypsis to thermoregulation and its purpose has been a lively source of debate in biology for over a century. Determining the effects of both ...habitat and human influences on pelt color patterns can be difficult. We made novel use of a multispecies occupancy model by defining “pelt color” as “species.” We then used this model to test predictions and estimate pelt color patterns concurrently for three carnivore species in Idaho, United States. We predicted pelt patterns of all three carnivores would be affected by environmental variables as well as human disturbance. Areas of Idaho where baiting was allowed and preferential harvest possible did not explain pelt patterns in black bears and neither did forest cover. Road density was positively associated with detection probability but negatively associated with occupancy of both black and brown pelt bears, however. Gray pelt wolves were found more often in areas with higher road densities than black wolves. As predicted, black, but not gray, wolves were positively associated with forest cover. Both red and black pelt foxes were positively associated with increasing elevation and road density. Black pelt foxes were negatively associated with forest cover, mirroring the habitat use described for native black pelt foxes. We demonstrate how using noninvasively collected data and extending multispecies occupancy models can allow biologists to study the distribution of different pelt colors in wild populations.
Monitoring rare and elusive carnivores is inherently challenging because they often occur at low densities and require more resources to effectively assess status and trend. The fisher (Pekania ...pennanti) is an elusive mesocarnivore endemic to North America; in its western populations it is classified as a species of greatest conservation need. During winter of 2018–2019, we deployed remotely triggered cameras in randomly selected, spatially balanced 7.5‐km × 7.5‐km grid cells across a broad study area in western Montana, Idaho, and eastern Washington, USA. As part of this large‐scale, multi‐state monitoring effort, we conducted an occupancy assessment of the Northern Rocky Mountain fisher population at a range‐wide scale. We used non‐spatial occupancy models to determine the current extent of fisher occurrence in the Northern Rocky Mountains and to provide baseline occupancy estimates across a broad study area and a refined sampling frame for future monitoring. We used a spatial occupancy model to determine patterns in fisher occurrence across their Northern Rocky Mountain range while explicitly correcting for spatially induced overdispersion. Additionally, we assessed factors that influenced fisher occurrence through covariate occupancy modeling that considered predicted fisher habitat, site‐level environmental characteristics, and the influence of available harvest records (incidental and regulated). We detected fishers in 32 out of 318 (10%) of our surveyed cells, and estimated that overall, 160 (14%; 95% CI = 115–218) of 1,143 grid cells were occupied by fishers. Fisher occupancy was positively associated with our stratum that contained cells with a greater proportion of predicted fisher habitat and with proximity to nearest 2000–2015 harvest location. Fisher occupancy was weakly and positively associated with increased canopy cover. Our spatial model identified 2 areas with higher predicted occupancy: a large area across the Idaho Nez Perce‐Clearwater National Forest, and a smaller area in the Cabinet Mountain Range crossing the northern border of Idaho and Montana. We used spatial occupancy results from our original sampling frame to create a biologically derived refined sampling frame for future monitoring. Within the bounds of our refined sampling frame, we estimated that 155 (22%; 95% CI = 110–209) of 700 grid cells were occupied by fishers. By incorporating our increasing understanding of fisher habitat with contemporary analytical techniques, we defined current range‐wide occupancy of the Northern Rocky Mountain fisher population, identified core areas of fisher occurrence for future conservation efforts, and used our model results to create a refined sampling frame for future fisher monitoring in the Northern Rocky Mountains.
We provide occupancy and detection probability data from the first multi‐state, range‐wide study of the Northern Rocky Mountain fisher population. We provide baseline data for comparison against future fisher surveys as well as a study design and protocol to conduct future surveys.
Coexistence between sympatric predators is achieved through a variety of behaviors that reduce competitive interactions. We examined fine-scale co-occurrence between sympatric apex predators across a ...large and highly variable landscape characterized by anthropogenic presence and related mortality in Idaho, USA. We analyzed data from 201 camera traps across 130,000 km
2
to examine spatiotemporal associations between four apex predators: humans (
Homo sapiens
), wolves (
Canis lupus
), black bears (
Ursus americanus
), and cougars (
Puma concolor
). We hypothesized that the dominant competitors in our system would be associated with reduced detections of subordinate competitors (i.e., humans > wolves > black bears > cougars). Such a hierarchy proved true only when examining spatial associations between humans and wolves. We found a positive spatial association between black bear and cougars, suggesting that cougar kills may provide scavenging opportunities for bears. Although we found a slight positive spatial association between black bears and wolves, we found strong differences in temporal activity patterns between them. Mesic forest yielded higher detections of all predators (except humans) compared to xeric habitat. Cougars in particular appeared to be better predicted by habitat than presence of sympatric predators with more detections in mesic compared to mountain and xeric habitats. Understanding the co-occurrence of apex predators in a system is not a simple measure of their relative dominance cascading from one level to the next.
