Resource selection is a fundamental ecological process impacting population dynamics and ecosystem structure. Understanding which factors drive selection is vital for effective species- and landscape-level management. We used resource selection probability functions (RSPFs) to study the influence of two forms of wolf (Canis lupus) predation risk, snow conditions and habitat variables on white-tailed deer (Odocoileus virginianus), elk (Cervus elaphus) and moose (Alces alces) resource selection in central Ontario's mixed forest French River-Burwash ecosystem. Direct predation risk was defined as the frequency of a predator's occurrence across the landscape and indirect predation risk as landscape features associated with a higher risk of predation. Models were developed for two winters, each at two spatial scales, using a combination of GIS-derived and ground-measured data. Ungulate presence was determined from snow track transects in 64 16- and 128 1-km(2) resource units, and direct predation risk from GPS radio collar locations of four adjacent wolf packs. Ungulates did not select resources based on the avoidance of areas of direct predation risk at any scale, and instead exhibited selection patterns that tradeoff predation risk minimization with forage and/or mobility requirements. Elk did not avoid indirect predation risk, while both deer and moose exhibited inconsistent responses to this risk. Direct predation risk was more important to models than indirect predation risk but overall, abiotic topographical factors were most influential. These results indicate that wolf predation risk does not limit ungulate habitat use at the scales investigated and that responses to spatial sources of predation risk are complex, incorporating a variety of anti-predator behaviours. Moose resource selection was influenced less by snow conditions than cover type, particularly selection for dense forest, whereas deer showed the opposite pattern. Temporal and spatial scale influenced resource selection by all ungulate species, underlining the importance of incorporating scale into resource selection studies.
Aim Understanding carnivore distribution is important for management decisions that aim to restore naturally regulated ecosystems and preserve biodiversity. Eastern Wolves, a species at risk in Canada, are centralized in Algonquin Provincial Park and their ability to disperse and establish themselves elsewhere is limited by human-caused mortality associated with hunting, trapping and vehicle collisions. Here, we refine our understanding of Eastern Wolf distribution and provide the first estimates of their effective population size.Location Southern Ontario and Gatineau Quebec.Methods We used non-invasive samples, as well as blood samples archived from other research projects, collected between 2010 and 2014 to generate autosomal microsatellite genotypes at 12 loci for 98 Canis individuals. We utilized Bayesian and multivariate clustering analyses to identify Eastern Wolves in regions that were previously unsampled. Both linkage disequilibrium and temporal approaches were used to estimate effective population size of Eastern Wolves.Results Assignment tests identified 34 individuals as Eastern Wolves, primarily in or near two provincial parks: Killarney and Queen Elizabeth II Wildlands. Eastern Coyotes were identified in Bon Echo Provincial Park, Frontenac Provincial Park and Gatineau Park, whereas many of the samples were admixed among the different Canis types. Effective population size (N e ) estimates ranged from 24.3 to 122.1 with a harmonic mean of 45.6.Main conclusions The identification of Eastern Wolves in the regions of Killarney and Queen Elizabeth II Wildlands Provincial Parks extends the range of Eastern Wolves north of the French River and southward into previously unidentified regions. The effective population size is low and raises concerns for long-term persistence of this threatened carnivore; estimates are dangerously close to critical values recommended for short-term persistence. These results provide important information for upcoming Eastern Wolf recovery plans associated with federal and provincial endangered species legislation.
The cane or marine toad (Chaunus marinus, formerly Buto marinus) was introduced to the Northern Mariana Islands starting in the 1930s. The effects of this exotic predator on native vertebrates (especially lizards) are largely unknown. We analysed the stomach contents of 336 cane toads collected from the island of Rota, with the goal of estimating the level of toad predation on native vertebrates. Beetles, ants, millipedes, and grasshoppers/crickets comprised the majority of prey classes consumed by toads. The introduced Brahminy blindsnake (Ramphotyphlops braminus; N = 6) and conspecific cane toads (N = 4) were the vertebrates most commonly found in toad stomachs. Skinks (Emoia; N = 2) were the only native vertebrates represented in our sample. The small numbers of nocturnal terrestrial vertebrates native to Rota likely translates to relatively low rates of predation by cane toads on native vertebrates.
The cover image, by Linda Rutledge et al., is based on the Biodiversity Research Patchy distribution and low effective population size raise concern for an at‐risk top predator, DOI: . Photo Credit: Michael Runtz.
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