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Roadside mineral licks form when road salt used to de-ice highways in winter runs off road surfaces and accumulates in roadside ditches. Some ungulates are attracted to these roadside licks [...]

Climate change is predicted to increase the frequency and size of wildfires. Wildfire burns can influence wildlife space use, but prior to understanding the relationship between wildlife and burns, the extent of wildfires and the regrowth of burned areas must be determined. We used remotely sensed, multispectral satellite imagery to calculate differenced normalized burn ratios (NBRs) to define areas burned by wildfire and assess temporal trends in burn frequency and extent in central British Columbia. We then used NBRs as an index of vegetation regrowth to model regrowth trajectories within burns. Next, we examined spatial responses to burns by a moose (Alces alces) population that recently declined in abundance. We utilized locations used by and available to collared moose to determine spatial responses as a function of years since wildfire and vegetation regrowth. We also assessed functional responses to burns by moose, dependent upon the proportion of burned areas available to each individual. We hypothesized that (h1) wildfire burns within our study area increased from 1985 to 2017, (h2) that moose increase their use of burns in comparison with availability as burns age as a result of vegetation regrowth, and (h3) that moose demonstrate functional responses to burns (i.e., selection of burns by individual moose declines as the amount of burned areas increases). We observed that the frequency and extent of burns are increasing within our study area. In contrast to h2, moose in summer and fall decreased the selection of burns as burns aged. We, however, observed that moose responded most positively to locations with intermediate vegetation regrowth (i.e., NBR values), which according to burn regrowth trajectories were most likely to be achieved 13 or more years post‐wildfire; given that most burns within our study area were ≤13 years of age, we predict that the use of burns will likely increase as vegetation regrows. Moose only selected for burns in fall, and we did not find support for the presence of a functional response. Our research demonstrated the utility of remotely sensed imagery and NBRs to define burn locations and to reveal current and probable future spatial responses to burns by a wildlife population of concern. [ABSTRACT FROM AUTHOR]

Gray wolves (Canis lupus) were reintroduced to Idaho, USA, in 1995–1996. The removal of Endangered Species Act protections in 2011 transferred wolf management to the state where wolves were subsequently classified as a harvested (i.e., hunted, trapped) big game species. We implemented a camera‐based survey across Idaho from 2016–2021 as part of a population monitoring program. We used the resulting camera images in multi‐year, dynamic and single‐season occupancy models to examine potential changes in the asymptotic proportion of area occupied by wolves and assess the effect of cumulative wolf harvest from 2016–2021 on occupancy in the last year of the study, 2021. We also wanted to understand how habitat, prey, humans, harvest, livestock, and prey‐related wolf removals affected wolf occupancy through their effects on colonization and extinction of occupancy cells through time. Statewide wolf occupancy did not change appreciably over the course of our study, with the proportion of survey cells occupied at an estimated high of 0.44 ± 0.03 (SE) in 2018 and a low of 0.39 ± 0.03 in 2020. Wolf colonization (i.e., probability that a cell switched from unoccupied to occupied between years) was positively associated with forest cover, images of humans, and the percent of neighboring cells that were occupied. Cell extinction (i.e., probability of switching from occupied to unoccupied between years) was negatively associated with neighboring cell occupancy. There were non‐linear relationships between wolf harvest, colonization, and extinction. The single‐season occupancy model demonstrated a positive relationship between harvest and occupancy at low to moderate levels of harvest (10–30%), but there was also evidence that high levels of harvest (>30%) reduce occupancy. Our results indicate that although harvest might influence wolf occupancy at local scales, wolf occupancy remained relatively constant across the state and wolves remained well distributed across Idaho during the study. [ABSTRACT FROM AUTHOR]

Generalist predators typically have broad diets, but their diets may become constrained when one species of prey becomes disproportionately available. Yet there is poor understanding regarding whether generalist predators exhibit stereotypic relationships with pulsed prey resources. We used telemetry data from 959 woodland caribou (Rangifer tarandus caribou (Gmelin, 1788); 146 adult females, 813 calves), 61 coyotes (Canis latrans Say, 1823), and 55 black bears (Ursus americanus Pallas, 1780) to investigate how two generalist predators interacted with caribou neonates on the island of Newfoundland. We examined the similarity of patterns of habitat use between caribou and their predators across time and related this similarity to interspecific spatiotemporal co-occurrence and mortality risk for caribou neonates. The similarity in habitat use between coyotes and caribou mirrored variation in juvenile hazard risk, but had weak association with actual co-occurrence with caribou. Bears and caribou exhibited less similarity in habitat use during the calving season than coyotes and caribou. The relationship between habitat use of bear and caribou did not correspond with either co-occurrence patterns or overall risk for caribou neonates. Our work illustrates how risk for a prey species can be shaped differently based upon differences between the behavioural strategies of generalist predator species. Key words: black bear, Ursus americanus, woodland caribou, Rangifer tarandus caribou, coyote, Canis latrans, neonates, Newfoundland, predator-prey interactions, specialist-generalist predators. Les predateurs generalistes presentent typiquement des regimes alimentaires varies, mais ces derniers peuvent devenir restreints quand la disponibilite d'une espece de proie devient disproportionnement grande. Cela dit, la possibilite qu'il existe des relations stereotypees de predateurs avec des ressources de proies pulsees est mal comprise. Nous avons utilise des donnees de telemetrie sur 959 caribous des bois (Rangifer tarandus caribou (Gmelin, 1788), 146 femelles adultes, 813 veaux), 61 coyotes (Canis latrans Say, 1823) et 55 ours noirs (Ursus americanus Pallas, 1780) pour etudier les interactions de deux predateurs generalistes avec des caribous nouveau-nes dans Pile de Terre-Neuve. Nous avons examine la similitude des motifs d'utilisation de l'habitat entre les caribous et leurs predateurs dans le temps et relie cette similitude a la cooccurrence spatiotemporelle interspecifique et au risque de mortalite pour les caribous nouveau-nes. La similitude de l'utilisation de l'habitat entre les coyotes et les caribous reflete les variations du risque de dangers pour les jeunes, mais n'est que faiblement associee a la cooccurrence avec les caribous. Les ours et les caribous presentent une moins grande similitude sur le plan de l'utilisation de l'habitat durant la saison de mise bas que les coyotes et les caribous. La relation entre l'utilisation de l'habitat par les ours et les caribous ne correspond pas avec les motifs de cooccurrence, ni avec le risque global pour les caribous nouveau-nes. Nos travaux illustrent les differentes incidences sur les risques pour une espece de proie de differentes strategies comportementales d'especes de predateurs generalistes. [Traduit par la Redaction] Mots-cles: ours noir, Ursus americanus, caribou des bois, Rangifer tarandus caribou, coyote, Canis latrans, nouveau-nes, Terre-Neuve, interactions predateur-proie, predateurs specialistes-generalistes., Introduction Predation is a key force shaping most ecosystems (Getz 2011) and one of the key drivers of animal evolution (Roff 1996). Predator-prey interactions are generally conceptualized as complex games [...]

Individuals in substandard physical condition are predicted to be more vulnerable to predation. Support for this prediction is inconsistent partly as a result of differences across systems in the life histories of predator and prey species. Our objective was to examine the physical condition of woodland caribou Rangifer tarandus caribou calves depredated by two predators with different life histories in Newfoundland, Canada. Black bears Ursus americanus are capable of chasing calves at high speeds over short distances and primarily prey on calves <1 month of age. Coyotes Canis latrans are cursorial predators that pursue prey over longer distances, which is expected to result in the selection of substandard individuals. We hypothesized that 1) black bears will kill calves in substandard physical condition, while 2) coyotes will kill calves from across the distribution of individual conditions. We used mitochondrial DNA species identification tests to assign predator species to calf mortalities. We then used molecular identifications and field observations to build a predictive model using generalized boosted trees to predict the predator species where a molecular identification was unavailable. We tested our hypotheses using Cox proportional hazards models under a competing risks framework. Bears killed younger calves and lighter calves, while coyotes killed heavier calves. Coyotes also killed more late-born calves, which might suggest prey switching as calves become more abundant later in the season. Our findings suggest that the physical constraints of predators play a greater role than predator hunting strategies in this system, but other processes are likely influential. The tendency for coyotes to kill heavier calves might result from sustained coyote predation over time, following the removal by black bears of lighter calves during their first month of age. This research illuminates the complexity of predator–prey interactions in Newfoundland and highlights an important source of variability for predator–prey systems. [ABSTRACT FROM AUTHOR]

Apex predators may influence carnivore communities through the suppression of competitively dominant mesopredators, however they also provide carrion subsidies that could influence foraging and competition among sympatric mesopredators when small prey is scarce. We assessed coyote Canis latrans and red fox Vulpes vulpes winter diet overlap and composition from scats collected in two study areas with 3‐fold difference in grey wolf Canis lupus density due to a wolf control program. We hypothesized that differences in diet composition would be driven by the use of carrion, and tested whether 1) apex predators facilitate resource overlap, or 2) apex predators facilitate resource partitioning. We estimated the available biomass of snowshoe hares and voles based on pellet density and vole capture rates in each study area. We used molecular analysis to confirm species identification of predator scats, and used microscopic evaluation of prey remains to analyze diet composition of 471 coyote and fox scats. Ungulate carrion, voles and snowshoe hares comprised 73% of coyote and fox diet, and differences in use of carrion and microtines accounted for nearly 60% of the dissimilarity in diet among these canids. Carrion was the top‐ranked item in the coyote diet in both study areas, whereas carrion use by red foxes declined 3‐fold in the study area with higher wolf and small prey abundance. Diet overlap tended to be lower and diet diversity tended to be higher where wolves were more abundant, though these trends were not statistically significant. Taken together, our findings indicate that carrion provisions could facilitate resource partitioning in mesocarnivore communities by alleviating exploitation competition for small mammals. [ABSTRACT FROM AUTHOR]

Predator species identification is an important step in understanding predator-prey interactions, but predator identifications using kill site observations are often unreliable. We used molecular tools to analyse predator saliva, scat and hair from caribou calf kills in Newfoundland, Canada to identify the predator species, individual and sex. We sampled DNA from 32 carcasses using cotton swabs to collect predator saliva. We used fragment length analysis and sequencing of mitochondrial DNA to distinguish between coyote, black bear, Canada lynx and red fox and used nuclear DNA microsatellite analysis to identify individuals. We compared predator species detected using molecular tools to those assigned via field observations at each kill. We identified a predator species at 94% of carcasses using molecular methods, while observational methods assigned a predator species to 62.5% of kills. Molecular methods attributed 66.7% of kills to coyote and 33.3% to black bear, while observations assigned 40%, 45%, 10% and 5% to coyote, bear, lynx and fox, respectively. Individual identification was successful at 70% of kills where a predator species was identified. Only one individual was identified at each kill, but some individuals were found at multiple kills. Predator sex was predominantly male. We demonstrate the first large-scale evaluation of predator species, individual and sex identification using molecular techniques to extract DNA from swabs of wild prey carcasses. Our results indicate that kill site swabs (i) can be highly successful in identifying the predator species and individual responsible; and (ii) serve to inform and complement traditional methods. [ABSTRACT FROM AUTHOR]

The influence of study design on the ability to detect the effects of landscape pattern on gene flow is one of the most pressing methodological gaps in landscape genetic research. To investigate the effect of study design on landscape genetics inference, we used a spatially-explicit, individual-based program to simulate gene flow in a spatially continuous population inhabiting a landscape with gradual spatial changes in resistance to movement. We simulated a wide range of combinations of number of loci, number of alleles per locus and number of individuals sampled from the population. We assessed how these three aspects of study design influenced the statistical power to successfully identify the generating process among competing hypotheses of isolation-by-distance, isolation-by-barrier, and isolation-by-landscape resistance using a causal modelling approach with partial Mantel tests. We modelled the statistical power to identify the generating process as a response surface for equilibrium and non-equilibrium conditions after introduction of isolation-by-landscape resistance. All three variables (loci, alleles and sampled individuals) affect the power of causal modelling, but to different degrees. Stronger partial Mantel r correlations between landscape distances and genetic distances were found when more loci were used and when loci were more variable, which makes comparisons of effect size between studies difficult. Number of individuals did not affect the accuracy through mean equilibrium partial Mantel r, but larger samples decreased the uncertainty (increasing the precision) of equilibrium partial Mantel r estimates. We conclude that amplifying more (and more variable) loci is likely to increase the power of landscape genetic inferences more than increasing number of individuals. [ABSTRACT FROM AUTHOR]

• The influence of forestry cutblocks on moose (Alces alces) differs across systems. • Moose use and selection of cutblocks is influenced by successional stage. • Vegetation composition and regrowth drive regional moose responses to cutblocks. • Moose populations might tolerate more intense logging in more productive areas. • Managers should consider vegetation composition and regrowth in forestry planning. Forestry activities are globally widespread and can have a large positive or negative influence on wildlife. Wildlife responses to forestry cutblocks (defined areas where trees were harvested) vary as a function of forest succession, which differs across systems. Across their distribution, moose (Alces alces) and forestry are often closely associated. Moose are predicted to select for cutblocks because of greater browse quantity in early successional vegetation, but moose responses to cutblocks are inconsistent across studies. Our objective was to compare moose spatial responses to cutblocks as a function of year since cut between study areas (Prince George South [PGS] and Bonaparte [BP]) while considering differences in vegetation composition and regrowth to better inform forestry planning in British Columbia, Canada. We characterized cutblocks by dominant tree species as a proxy for vegetation composition and estimated the normalized burn ratio (NBR) from multispectral satellite imagery as an index of vegetation regrowth (i.e., structure). We then examined the use of cutblocks by moose dependent upon vegetation composition and NBR using generalized additive mixed effects models. Next, we used locations of collared moose and nearby available locations to examine moose responses as a function of year since cut and used those responses to group cutblocks into age classes, which were incorporated into resource selection functions (RSF) to compare moose responses between study areas. Vegetation composition differed between study areas, and although cutblocks in both study areas followed similar regrowth trajectories, NBRs for cutblocks > 13 years post-logging in PGS exceeded those in BP. Moose demonstrated greater use of locations within cutblocks with intermediate NBRs and dominanted by spruce (Picea engelmannii × glauca) versus Douglas fir (Pseudotsuga menziesii var. glauca). Moose responses as a function of year since cut varied seasonally, but across seasons, moose tended to avoid new cutblocks (1–8 years), select for regenerating cutblocks (9–24 years), and avoid older cutblocks (25–40 years). In both study areas, RSFs revealed that moose avoided new cutblocks, but moose in PGS were more likely to select for regenerating cutblocks in comparison to BP. Our analyses suggest that the use of cutblocks by moose is a function of year since cut, vegetation composition, and vegetation regrowth, likely resulting from differences in browse quantity and lateral cover. To maintain stable moose populations, managers should consider vegetation composition and regrowth during forestry planning, and future research should focus on identifying region-specific forestry thresholds for moose. [ABSTRACT FROM AUTHOR]