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Kelly, WY, United States

Lendrum P.E.,Panthera | Elbroch L.M.,Panthera | Quigley H.,Panthera | Thompson D.J.,Wyoming Game and Fish | And 2 more authors.
Journal of Zoology | Year: 2014

Cougars Puma concolor are described as 'habitat generalists', but little is known about which ecological factors drive their home range selection. For example, how do resource distributions and inter-species competition with dominant competitors (i.e. wolves, Canis lupus) over such resources, influence the distributions of cougars on the landscape? We tracked cougars using Very High Frequency (VHF; 2001 to 2005) and GlobalPositioningSystem (GPS; 2006 to 2011) technology in the Southern Yellowstone Ecosystem (SYE) in northwestern Wyoming, USA. We tested whether data type (VHF vs. GPS), cougar sex, access to forests (refugia) or hunt opportunity explained the size of 50% and 95% kernel density estimator (KDE) home ranges. Second, we quantified attributes of cougar home ranges and tested whether they were different from attributes of the overall study area, to address the ecological question: Do cougars select home ranges based on the availability of refugia, hunt opportunity or some combination of the two? Cougar sex and data type proved significant predictors of home range size for both 95% and 50% KDEs, and the amount of forest partly explained the size of 50% KDEs. Cougar home ranges derived from VHF data were 1.4-1.9 times larger than home ranges derived from GPS data; however, home range attributes determined from VHF and GPS data were remarkably equivalent. Female cougars selected home ranges with higher hunt opportunity than males, supporting the assumption that females primarily select home ranges with suitable prey to sustain themselves and their young. All cougars selected home ranges further from known wolf packs, providing evidence for newly established competition between resident cougars and recolonizing wolves, but did not select home ranges with greater access to landscape refugia. Our results provided evidence that cougars in the SYE select home ranges that provide high hunting opportunity and a spatial buffer that mitigates potential conflicts with a dominant competitor. © 2014 The Zoological Society of London. Source

Newby J.R.,University of Montana | Scott Mills L.,University of Montana | Ruth T.K.,Wildlife Conservation Society | Pletscher D.H.,University of Montana | And 4 more authors.
Biological Conservation | Year: 2013

An understanding of how stressors affect dispersal attributes and the contribution of local populations to multi-population dynamics are of immediate value to basic and applied ecology. Puma (Puma concolor) populations are expected to be influenced by inter-population movements and susceptible to human-induced source-sink dynamics. Using long-term datasets we quantified the contribution of two puma populations to operationally define them as sources or sinks. The puma population in the Northern Greater Yellowstone Ecosystem (NGYE) was largely insulated from human-induced mortality by Yellowstone National Park. Pumas in the western Montana Garnet Mountain system were exposed to greater human-induced mortality, which changed over the study due to the closure of a 915km2 area to hunting. The NGYE's population growth depended on inter-population movements, as did its ability to act as a source to the larger region. The heavily hunted Garnet area was a sink with a declining population until the hunting closure, after which it became a source with positive intrinsic growth and a 16× increase in emigration. We also examined the spatial and temporal characteristics of individual dispersal attributes (emigration, dispersal distance, establishment success) of subadult pumas (N=126). Human-caused mortality was found to negatively impact all three dispersal components. Our results demonstrate the influence of human-induced mortality on not only within population vital rates, but also inter-population vital rates, affecting the magnitude and mechanisms of local population's contribution to the larger metapopulation. © 2012 Elsevier Ltd. Source

Bartnick T.D.,University of Wisconsin - Madison | van Deelen T.R.,University of Wisconsin - Madison | Quigley H.B.,Panthera | Craighead D.,Craighead Beringia South
Canadian Journal of Zoology | Year: 2013

We examined predation habits of cougars (Puma concolor (L., 1771)) following the recent recovery of gray wolves (Canis lupus L., 1758) in the southern Greater Yellowstone Ecosystem. With the extirpation of wolves in the early 20th century, cougars likely expanded their niche space to include space vacated by wolves, and increased use of habitat better suited to the foraging of a coursing predator, like wolves. We predicted that as wolves recolonized their former range, competitive exclusion would compel cougars to cede portions of niche space occupied in the absence of wolves. To examine this hypothesis, we radio-tracked cougars and examined their predation sites from winter 2000-2001 through summer 2009. Variation in foraging by cougars was associated with increasing wolf presence. As wolf numbers increased and the mean distance between wolf pack activity centers and cougar predation sites decreased, cougars made kills at higher elevations on more north-facing slopes during summer and in more rugged areas during winter. In addition, cougars preyed on a higher proportion of mule deer (Odocoileus hemionus (Rafinesque, 1817)), consistent with predictions of exploitative competition with wolves. Observed changes in predation characteristics reflect differences in predation strategy between cougars and wolves, given that wolves are coursing predators and cougars are ambush predators. These possible predation effects should be considered when developing management strategies in systems where the recolonization of wolves may occur. Source

Mark Elbroch L.,Panthera | Lendrum P.E.,Panthera | Newby J.,Craighead Beringia South | Quigley H.,Panthera | Thompson D.J.,Wyoming Game and Fish
Zoological Studies | Year: 2015

Background: Niche differentiation may betray current, ongoing competition between two sympatric species or reflect evolutionary responses to historic competition that drove species apart. The best opportunity to test whether ongoing competition contributes to niche differentiation is to test for behavioral shifts by the subordinate competitor in controlled experiments in which the abundance of the dominant competitor is manipulated. Because these circumstances are difficult to coordinate in natural settings for wide-ranging species, researchers seize opportunities presented by species reintroductions. We tested for new competition between reintroduced wolves and resident cougars in the Southern Yellowstone Ecosystem to assess whether wolves might be impacting the realized niche of sympatric cougars. Results: Between 2002 and 2012, a period during which wolves increased from 15 to as high as 91 in the study area, cougars significantly increased the percentage of deer and decreased the percentage of elk in their diet in summer. Our top models explaining these changes identified elk availability, defined as the number of elk per wolf each year, as the strongest predictor of changing cougar prey selection. Both elk and deer were simultaneously declining in the system, though deer more quickly than elk, and wolf numbers increased exponentially during the same time frame. Therefore, we concluded that prey availability did not explain prey switching and that competition with wolves at least partially explained cougar prey switching from elk to deer. We also recorded 5 marked cougar kittens killed by wolves and 2 more that were killed by an undetermined predator. In addition, between 2005 and 2012, 9 adult cougars and 10 cougar kittens died of starvation, which may also be in part explained by competition with wolves. Conclusions: Direct interspecific predation and shifting cougar prey selection as wolves increased in the system provided evidence for competition between recolonizing wolves and resident cougars. Through competition, recolonizing wolves have impacted the realized niche of resident cougars in the Southern Yellowstone Ecosystem (SYE), and current resident cougars may now exhibit a realized niche more reflective of an era when these species were previously sympatric in the Yellowstone Ecosystem. © 2015 Elbroch et al. Source

Bui T.-V.D.,University of Washington | Marzluff J.M.,University of Washington | Bedrosian B.,Craighead Beringia South
Condor | Year: 2010

Anthropogenic changes in landscapes can favor generalist species adapted to human settlement, such as the Common Raven (Corvus corax), by providing new resources. Increased densities of predators can then negatively affect prey, especially rare or sensitive species. Jackson Hole and the upper Green River valley in western Wyoming are experiencing accelerated rates of human development due to tourism and natural gas development, respectively. Increased raven populations in these areas may negatively influence the Greater Sage-Grouse (Centrocercus urophasianus), a sensitive sagebrush specialist. We investigated landscape-level patterns in raven behavior and distribution and the correlation of the raven data with the grouse's reproductive success in western Wyoming. In our study areas towns provide ravens with supplemental food, water, and nest sites, leading to locally increased density but with apparently limited (<3 km) movement by ravens from towns to adjacent areas of undeveloped sagebrush. Raven density and occupancy were greatest in land covers with frequent human activity. In sagebrush with little human activity, raven density near incubating and brooding sage-grouse was elevated slightly relative to that expected and observed in sagebrush not known to hold grouse. Raven occupancy near sage-grouse nests and broods was more highly correlated with sage-grouse success than were raven density and behavior, suggesting that the majority of nest predation by ravens is most likely carried out by resident territorial individuals. Integrated region-wide improvement of sagebrush habitat, removal of anthropogenic subsidies, and perhaps removal or aversive conditioning of offending ravens might benefit sage-grouse populations inour study area. © The Cooper Ornithological Society 2010. Source

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