Evaluating the influence of water developments on the demography and spatial ecology of a rare, desert-adapted carnivore: the kit fox (\u3ci\u3eVulpes macrotis\u3c/i\u3e)

Constructing water developments to support anthropogenic activities and particular fauna is pervasive across many arid regions of the globe. Despite their prevalence and a predicted increase as a management and conservation tool, water developments may have complex and unanticipated impacts on wildlife. For example, the addition of water developments to the Great Basin Desert in the western United States may have indirectly contributed to a decrease in distribution and abundance of kit foxes (Vulpes macrotis). From 2010 to 2013, we examined survival, relative abundance, and habitat characteristics of kit foxes in relation to water developments on the U.S. Army Dugway Proving Ground, Utah, using a before-after control-impact design. We collected 2 years of baseline data prior to reducing availability of water and continued data collection for another 2 years after removal of water on one-half of the study area. We found no evidence that removing water influenced survival or abundance of kit foxes. In addition, we found areas associated with the majority of water developments differed from current kit fox territories in elevation, soil type, and dominant cover type; historical use by kit foxes of areas associated with water developments is largely unknown. One explanation for our inability to find support for a water effect is that observed changes in the kit fox population and canid community in the Great Basin are attributable to changes in coyote management practices that temporally coincided with, but were largely unrelated to increases in water availability

Cougar Predation Rates and Prey Composition in the Pryor Mountains of Wyoming and Montana

Understanding predator-prey dynamics is a fundamental principle of ecology and an ideal component for management decisions. Across North America, the impact of cougars (Puma concolor) on their prey varies regionally. To document the relationships between cougars, bighorn sheep (Ovis canadensis canadensis), mule deer (Odocoileus hemionus), and feral horses (Equus caballus) on the Bighorn Canyon National Recreation Area and the Pryor Mountains, we deployed GPS collars on 6 cougars (the total number residing on the study area), and visited their clusters to determine predation rates and foraging patterns. We examined the composition of cougar kills by species, mule deer sex-age classes, prey size classes, season, and cougar sex. As a measure of selection, we examined the composition of prey killed relative to the composition of ungulates obtained during an aerial survey. We found mule deer were the primary prey, while bighorn sheep constituted secondary prey. While cougars selected for bighorn sheep, this was attributable to a single cougar. Among mule deer, female cougars killed more does and male cougars killed more bucks. Family groups had the highest predation rates (i.e., the shortest time intervals between kills), while adult males had the lowest rate. During the study, cougars were not depredating any feral horses in the area. Maintaining predator and prey numbers will require agencies to monitor and manage all fauna within this complex ecosystem. Habitat manipulations may be necessary to increase populations of deer and bighorn sheep, while continued management of feral horses will be required to reduce competition with native ungulates

Relaxin as a diagnostic tool for pregnancy in the coyote (\u3ci\u3eCanis latrans\u3c/i\u3e)

The diagnosis of pregnancy in the domestic dog (Canis familiaris) often employs specialized equipment, experienced staff, and the cooperation of the bitch. These procedures can be challenging when the subject is a wild canid, particularly in a field setting. In addition, reproductive hormone assays are unreliable as a diagnostic tool because the estrous profiles of pregnant and pseudopregnant canines are similar. However, research has demonstrated that the hormone relaxin can be detected in maternal blood after embryonic implantation, but remains negligible in non-pregnant females. We investigated the use of relaxin as a diagnostic marker of pregnancy in the coyote (C. latrans). A commercially available canine relaxin enzyme immunoassay (ReproCHEKTM) was used to test plasma collected from 124 female coyotes over four consecutive breeding seasons. Mating activities of the captive females were observed; then peripheral blood samples were collected at intervals throughout pregnancy, as well as after parturition. Results demonstrated that relaxin could be detected in the plasma of pregnant coyotes after 28 days of gestation, and in some cases as early as 23 days, while non-pregnant females and male coyotes consistently tested negative. Relaxin also remained detectable in the plasma of the majority of females tested 10–12 weeks after parturition. This qualitative assay for relaxin proved to be a reliable diagnostic tool for pregnancy in the coyote. In addition, blood sampling was relatively easy, could be accomplished with minimal handling, and did not require sedation or anesthesia

Evaluating the influence of water developments on the demography and spatial ecology of a rare, desert-adapted carnivore: the kit fox (\u3ci\u3eVulpes macrotis\u3c/i\u3e)

Constructing water developments to support anthropogenic activities and particular fauna is pervasive across many arid regions of the globe. Despite their prevalence and a predicted increase as a management and conservation tool, water developments may have complex and unanticipated impacts on wildlife. For example, the addition of water developments to the Great Basin Desert in the western United States may have indirectly contributed to a decrease in distribution and abundance of kit foxes (Vulpes macrotis). From 2010 to 2013, we examined survival, relative abundance, and habitat characteristics of kit foxes in relation to water developments on the U.S. Army Dugway Proving Ground, Utah, using a before-after control-impact design. We collected 2 years of baseline data prior to reducing availability of water and continued data collection for another 2 years after removal of water on one-half of the study area. We found no evidence that removing water influenced survival or abundance of kit foxes. In addition, we found areas associated with the majority of water developments differed from current kit fox territories in elevation, soil type, and dominant cover type; historical use by kit foxes of areas associated with water developments is largely unknown. One explanation for our inability to find support for a water effect is that observed changes in the kit fox population and canid community in the Great Basin are attributable to changes in coyote management practices that temporally coincided with, but were largely unrelated to increases in water availability

Resource Selection by Cougars: Influence of Behavioral State and Season

An understanding of how a predator uses the landscape can assist in developing management plans. We modeled resource selection by cougars (Puma concolor) during 2 behavioral states (moving and killing) and 2 seasons (summer and winter) with respect to landscape characteristics using locations from global positioning system (GPS)-collared cougars in the Pryor Mountains, Montana and Wyoming, USA. Furthermore, we examined predation-specific resource selection at 2 scales (fine and coarse). When possible, we backtracked from cache sites to kill sites and used a fine-scale analysis to examine landscape characteristics of confirmed kills. At this fine scale, kill sites had less horizontal visibility, were more likely to be in juniper (Juniperus spp.)-mountain mahogany (Cercocarpus ledifolius), and were less likely to be in grassland vegetation. For the coarse-scale analysis of predation risk, we used the entire dataset of kills by buffering each cache site by 94.9 m, which was the 95% upper cut-off point of the known distances dragged from kill sites to cache sites, thereby creating buffered cache sites that had a high probability of containing the kill site. We modeled seasonal cougar predation site selection by constructing resource selection functions for these buffered cache sites. The top model for summer predation risk consisted of vegetation class, distance to water, and slope. The top model for winter predation risk included vegetation class and elevation. These predation risk models were similar to but simpler than the resource selection models developed from the moving locations. Essentially, the behavioral state (i.e., killing vs. moving) of the cougar had little influence on resource selection, indicating that cougars are generally in hunting mode while moving through their landscape. To potentially reduce cougar predation on mule deer (Odocoileus hemionus) and bighorn sheep (Ovis canadensis) in our study area, managers can intersect the cougar predation-risk resource selection functions with deer and sheep habitat to guide habitat modification efforts aimed at increasing horizontal visibility in risky vegetation classes

THE ROLE OF PREDATION IN WILDLIFE POPULATION DYNAMICS

The role predation plays in the dynamics of prey populations is controversial. Our understandings of predator-prey relationships is complicated by a multitude of factors in the environment and a general lack of knowledge of most ecological systems. Various other factors, besides predation, may regulate or limit prey populations, and various factors influence the degree to which predation affects prey populations. Furthermore, some factors may create time lags, or even cause generational effects, that go unnoticed. Herein, we review the role of predation in wildlife population dynamics, some of the factors influencing predator-prey interactions, and attempt to indicate where the professional debate currently is focused and where it may need to go to enhance our understanding of predator-prey interactions

Resource Selection by Cougars: Influence of Behavioral State and Season

An understanding of how a predator uses the landscape can assist in developing management plans. We modeled resource selection by cougars (Puma concolor) during 2 behavioral states (moving and killing) and 2 seasons (summer and winter) with respect to landscape characteristics using locations from global positioning system (GPS)-collared cougars in the Pryor Mountains, Montana and Wyoming, USA. Furthermore, we examined predation-specific resource selection at 2 scales (fine and coarse). When possible, we backtracked from cache sites to kill sites and used a fine-scale analysis to examine landscape characteristics of confirmed kills. At this fine scale, kill sites had less horizontal visibility, were more likely to be in juniper (Juniperus spp.)-mountain mahogany (Cercocarpus ledifolius), and were less likely to be in grassland vegetation. For the coarse-scale analysis of predation risk, we used the entire dataset of kills by buffering each cache site by 94.9 m, which was the 95% upper cut-off point of the known distances dragged from kill sites to cache sites, thereby creating buffered cache sites that had a high probability of containing the kill site. We modeled seasonal cougar predation site selection by constructing resource selection functions for these buffered cache sites. The top model for summer predation risk consisted of vegetation class, distance to water, and slope. The top model for winter predation risk included vegetation class and elevation. These predation risk models were similar to but simpler than the resource selection models developed from the moving locations. Essentially, the behavioral state (i.e., killing vs. moving) of the cougar had little influence on resource selection, indicating that cougars are generally in hunting mode while moving through their landscape. To potentially reduce cougar predation on mule deer (Odocoileus hemionus) and bighorn sheep (Ovis canadensis) in our study area, managers can intersect the cougar predation-risk resource selection functions with deer and sheep habitat to guide habitat modification efforts aimed at increasing horizontal visibility in risky vegetation classes

Gray Wolves

Wolf conflicts are primarily related to predation on livestock, pets and other domestic animals, as well as their direct and indirect impacts on native ungulates (i.e., big game). Economic losses vary widely with some livestock producers facing high levels of depredation in some areas. This publication focuses on wolf ecology, damage, and management, particularly as it relates to wolf depredation on livestock and other conflicts with people. Wolves and people share the same environments more than people realize. In the U.S., wolves are not confined to wilderness areas. Though curious, wolves generally fear people and rarely pose a threat to human safety. Wolf attacks on people are, and always have been, very rare compared to other wildlife species. However, there have been several cases of human injuries and a few deaths due to wolves in North America over the past 100 years. The main factors contributing to these incidents were habituation to people, rabies infections, conditioning to human foods, and the presence of domestic dogs. It is unusual for wild wolves to associate or interact with people, linger near buildings, livestock, or domestic dogs, but it does occur especially in areas of high wolf densities in and around rural communities. This type of behavior may be more prevalent in areas where wolves are not legally harvested. This “bold” behavior is more typical of a habituated or food- conditioned animal, a released captive wolf, or a released wolf-dog hybrid. The scale and scope of wolf depredation on livestock depends on local wolf density; numbers and kinds of livestock; livestock husbandry practices; availability and vulnerability of alternative prey; human density; road density; severity of winters; and local hunting pressure. In many instances, wolves live around livestock without causing damage or only occasional damage. Wolf pack size has been shown to increase the likelihood of depredations on domestic animals, with larger packs more likely to cause damage. Most losses occur between April and October when livestock are on summer pastures or grazing allotments. Cattle, especially calves, are the most common livestock killed by wolves. When wolves kill sheep or domestic poultry, often multiple individuals are killed or injured. As of 2019, stable wolf populations exist in many regions in the U.S., including Alaska, Minnesota, Wisconsin, Michigan, Wyoming, Montana, and Idaho, with growing populations in parts of Oregon and Washington (Figures 19, 20). Wolves have recently been documented in northern California and northwestern Colorado. A small population of introduced Mexican wolves exists in Arizona and New Mexico, and a small population of red wolves exists in eastern North Carolina. Both the Mexican and red wolf populations are considered more vulnerable to extinction than other North American wolf populations

COYOTE POPULATION PROCESSES REVISITED

It appears that coyote (Canis latrans) abundance is determined primarily by availability of food (prey) as mediated through social dominance hierarchies and a territorial land tenure system. This is reflected in rates of reproduction, dispersal, and mortality, with survival of juveniles a major factor. Suggestions for a new generation of simulation models to explore coyote population functions are included