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Infection And Immiunity in Bighorn Sheep Metapopulations: Dynamics of Pneumonia
Get PDFIt is widely accepted that reducing contact between domestic and wild sheep limits pneumonia introduction, where domestic sheep transmit pathogens to bighorns. However, in some places, pneumonia persists for many years, even as local domestic in holding decline. We focused on one such system, the Hells Canyon region. We used an extensive long-term dataset to assess the evidence that pneumonia-causing pathogens induce an acquired immune response in bighorn sheep by reconstructing pneumonia exposure histories, and evaluating the impact an individual’s exposure history has on its survival. We found evidence of protective immunity lasting approximately two years, and saw that translocated individuals suffered much higher pneumonia risk than residents. Surviving many past pneumonia events decreased an adult’s risk in future events, although lambs born to ewes with many past exposures were at higher risk than their peers. These results are consistent with a disease that produces some chronic carriers that shed to their lambs for many years. Interestingly, while we might expect that the impact of chronic carriage on a population should decline over time and allow for population recovery (through senescence of carriers), we instead saw a trend of increasing lamb pneumonia mortality. Our findings corroborate long-held hypotheses about the presence of a chronic carrier state, and suggest that better understanding specific mechanisms leading to chronic carriage will help clarify the costs and benefits surrounding various management strategies
Lessons from Wolf Restoration in The Northwestern U.S.
Get PDFGray wolf (Canis lupus) populations were deliberately eliminated from nearly all of their historic range in the contiguous United States by 1930. Naturally dispersing wolves from Canada first denned in Montana in 1986. An intense period of scientific research, public outreach, and politics followed and resulted in wolves from western Canada being reintroduced to central Idaho and Yellowstone National Park, Wyoming in 1995 and 1996. The population grew rapidly and at least 1,600 wolves now live in Montana, Idaho, Wyoming, and parts of eastern Oregon and Washington (NRM). The population has been biologically recovered since December 2003 when at least 663 wolves were present but removal of federal protections was delayed for several years. Packs now occupy mountainous forested habitat in over 130,000 square miles of the NRM. Wolf restoration resulted in both benefits (public viewing, harvest opportunities, funding by tag sales, and restoration of ecological processes) and costs (agency funding, livestock and pet depredation, and competition with big game hunters). Federal, state, and tribal cooperators used a wide variety of deterrents, relocated wolves 117 times, and killed over 2,268 to reduce livestock conflicts. Wolves contributed to reducing some wild ungulate populations and harvest by hunters. Starting in 2009, states began to implement public harvest programs to provide hunter/trapper opportunity, reduce conflict, and meet other objectives. Up to one third of the minimum wolf population was legally killed by humans and as intended, it has helped stabilize the population and reduced conflicts. The NRM wolf population is now being managed similarly to other resident wildlife by the affected States (except Wyoming where litigation caused wolves to remain listed) and Native American Tribes. While the NRM wolf population is biologically healthy, controversy continues as legal, policy, political, and human value issues continue to be debated symbolically through wolves. I discuss the history, science, and politics behind restoring wolves to the NRM and possible implications to future wolf restoration efforts
Estimating Survival and Determining Causes of Mortality of Golden Eagles in South-Central Montana
Get PDFThere is concern for golden eagles (Aquilla chrysaetos) in the West as a result of contradictory population trend estimates and a likely increase in threats including but not limited to expanded wind energy development. Estimating survival of golden eagles and identifying causes of mortality can be used to assess the viability of nesting golden eagle populations and to direct mitigation efforts if necessary. To date, little information exists on golden eagle survival in western North America. In addition, identified causes of golden eagle mortality are often associated with an opportunity to find dead birds, creating a potential bias that may be minimized with the use of satellite telemetry. We outfitted 17 adult and 13 nestling golden eagles with satellite transmitters during the 2011-2014 nesting seasons near Livingston, Montana to estimate survival and determine causes of mortality. We used multi-state models to estimate survival over discrete-time periods for both adults and nestlings. Preliminary results showed our survival estimates were consistent with similar long-lived, slow reproducing raptors. Golden eagle mortalities in our study were a result of poisoning, intraspecific interaction and poaching. Our survival estimates are consistent with the stable density of breeding golden eagles in our study area and the primary causes of mortality differed from repository-based studies
Kodiak Brown Bears Surf the Salmon Red Wave: Direct Evidence from GPS Collared Individuals
Get PDFOne of the goals of Ecosystems Base Fisheries Management (EBFM) is recognizing and mitigating indirect effects of fisheries on trophic interactions. Most research on indirect effects has considered how the abundance of managed fishes influences trophic interactions with other species. However, recent work has shown that attributes besides abundance, such as life history variation, can strongly mediate species interactions. For example, phenological variation within prey species may enhance foraging opportunities for mobile predators by increasing the duration over which predators can target vulnerable life stages of prey. Here, we present direct evidence of individual brown bears (Ursus arctos middendorffi) exploiting variation in sockeye salmon spawning phenology by tracking salmon runs across a 2,800 km2 region of Kodiak Island. Data from 40 GPS collared brown bears show bears visited multiple spawning sites in synchrony with the order of spawning phenology. The average time spent feeding on salmon was 67 days, while the average duration of spawning for one population was only 40 days. The number of sites used was correlated with the number of days a bear exploited salmon, suggesting phenological variation in the study area influenced bear access to salmon, a resource which strongly influences bear fitness. These results suggest fisheries managers attempting to maximize harvest while minimizing impacts on brown bears should strive to protect the population diversity that underlies the phenological variation used by wildlife consumers. These results underscore the need to understand how fisheries affect life history diversity in addition to abundance in order to minimize negative effects of fisheries management on non-target species, a goal of EBFM
American Black Bear Population Fragmentation Determined Through Pedigrees in the Trans-Border Canada-United States Region
Get PDFFragmentation of species with large numbers of individuals in adjacent areas can be challenging to detect using genetic tools as there often is no differentiation because genetic drift occurs very slowly. We used a genetic-based pedigree analysis to detect fragmentation in the American black bear (Ursus americanus) across 2 highways with large adjacent populations. We used 20 locus microsatellite genotypes to detect parent-offspring and full sibling pairs within a sample of 388 black bears. We used the spatial patterns of capture locations of these first order relatives relative to US Highway 2 in northwest Montana and Highway 3 in southeast British Columbia to estimate the number of close relatives sampled across the highways (migrants/km of highway length) as an index of fragmentation. We compared these values to an expected migrant/km rate derived from the mean values of simulated fractures in the Highway 2 and Highway 3 region. We found evidence that these highway corridors were fragmenting black bear populations, but not completely. The observed migrant/km rate for Highway 2 was 0.05, while the expected rate was 0.21 migrants/km. Highway 3 had an observed migrant/km rate of 0.09 compared to the expected rate of 0.26. None of the 16 bears carrying GPS radio collars for 1 year crossed Highway 2, yet 6 of 18 crossed Highway 3. Pedigree and telemetry results were more closely aligned in the Highway 2 system evidencing more intense fragmentation than we found along Highway 3. Our results demonstrate that pedigree analysis may be a useful tool for investigating population fragmentation in situations where genetic signals of differentiation are too weak to determine migration rates using individual-based methods, such as population assignment
Grizzly Bear Scavenging of Carrion on the Northern Yellowstone Winter Range (1997-2012)
Get PDFThe Northern Yellowstone Winter Range (NYWR) in northwestern Wyoming and southwestern Montana is an important winter migratory destination for ungulates. The NYWR is within the Greater Yellowstone Ecosystem (GYE), a landscape characterized by a complex ecological system of predators, scavengers, and ungulates. Grizzly bears (Ursus arctos) are dominant members of the scavenging community throughout the spring. However, little is known about factors associated with grizzly bear use of carcasses. Of particular interest to managers is how habitat and anthropogenic factors are associated with carcass use. Such information, for example, may be useful to manage spring recreation in important bear foraging areas to reduce conflict and support conservation efforts. We used logistic regression to analyze spring survey data from 23 transects located in Yellowstone National Park and the Gallatin National Forest during 1997–2012, to identify factors associated with grizzly bear scavenging of winter- or predator-killed ungulates. Multi-model inference was used to evaluate relative support for a set of a priori candidate models containing environmental and temporal correlates. Our preliminary findings showed support for models with distance to forest edge, road density, and elevation. Results indicated negative relationships between these factors and probability of carcass use. Our results suggest that spatial heterogeneity in landscape-level habitat characteristics and human activity affect grizzly bear use of a valuable spring food source
Influence of Infanticide Risk on Brown Bear Den-Site Selection
Get PDFThe risk of infanticide in brown bears (Ursus arctos) may influence den-site selection and chronology for female brown bears with dependent young. Strategies to reduce risk of infanticide include females avoiding larger, more dominant adult males through spatialor temporal segregation. We assessed whether variation in den location, den habitat, and den entrance and emergence dates of male and female bears supported sexual segregation in Lake Clark National Park and Preserve, Alaska. Den-sites (n = 56) were located using GPS telemetry data from bears in 2014 (n = 21) and 2015 (n = 35). We used mixed model analysis of variance to compare slope, elevation, and aspect of den sites for adult male and adult female bears with and without dependent young. We also used these variables to model probable denning habitat using maximum entropy modeling. We examined timing of female den entry and emergence in relation to males using generalized linear mixed models. Our preliminary results using 2014 data suggest that females with dependent may den at higher elevations (944 ± 140 m, x ? ± SD) than solitary females (866 ± 189 m) but at lower elevations (984 ± 118 m) than males. They also may use less steep slopes (25 ± 11.8°) than solitary females (29 ± 9.9°) or males (34 ± 4.9°). Additionally, females with dependent young (Julian day: 289 ± 8 days) denned 2 days later than solitary females (287 ± 6 days) and 20 days earlier than males (309 ± 21 days). Females with dependent young (122 ± 17 days) also emerged from dens 6 days earlier than solitary females (128 ± 9 days) and 10 days earlier than males (132 ± 10 days). Differences in den entrance and emergence dates suggest support our hypothesis that females with dependent young temporally segregate from male bears
Developing Physiological Profiles using Nuclear Magnetic Resonance Spectroscopy to Inform Bighorn Sheep Management
Get PDFThis study employs new techniques using nuclear magnetic resonance (NMR) to assess the relative health, physiological condition, and reproductive function of wild bighorn sheep (Ovis canadensis) in Montana and Wyoming. Ongoing bighorn studies in Montana and the Greater Yellowstone Ecosystem are focused on herd attributes and the population dynamics which are affected by disease, climate, habitat and physiology. Indices of herd health and physiological status are typically obtained through expensive and time consuming lab assays and field measurements. Recently, NMR spectroscopy has been used to revolutionize the assessment of human metabolic health, and we expect that there is similar potential for studies of wildlife populations. Using NMR spectroscopy to assess metabolites associated with disease, nutrition and stress may eliminate the need for many traditional assays and techniques used today. NMR can be used to evaluate a large suite of metabolites associated with a variety of physiological functions from as little as 500 ?L of serum or plasma. Blood samples from 242 sheep from 13 different herds were collected during the winters of 2013-14 and 2014-15 to develop a comprehensive metabolite panel for bighorn sheep. We have used a recently developed statistical program known as MetaboAnalyst™ to begin to analyze and evaluate differences in NMR metabolic profiles among herds and across the fall-winter season when nutritional and physiological stress is expected to be acute. We will be presenting the results of this preliminary study and discussing the potential for application in wildlife management
Screening Montana Native Grass Species for Resitance to Spotted Knapweed Exudate Catechin (Poster)
Get PDFIt has been reported that catechin is an exudate of spotted knapweed (Centaurea maculosa). Documented to have chelating, antimicrobial and phytotoxic properties, catechin is believed to contribute to spotted knapweed’s ability to displace native plant communities. Originating in Europe, it is considered an invasive species in the Western United States and is recorded to have established populations in all fifty-six counties in Montana. Select plant species in Europe have demonstrated resistance to catechin without community displacement. It is hypothesized that the degree of resistance to catechin of neighboring plant species determines the degree of knapweed invasiveness. Using agar plates and several Montana grassland species, a bioassay was created to assess the degree of resistance of native grassland seeds to catechin. Assessed through percent germination, root length, and shoot length, the degree of resistance for each species was assessed. Identifying a Montana native grassland species with catechin resistance could provide potential means for knapweed prevention
Optimizing Wildlife Monitoirng Strategies in a Dynamic Setting (Poster)
Get PDFLong term, broadly distributed datasets are ideal for effective wildlife management. However, collecting and utilizing these data present a variety of challenges to management agencies. Idaho Department of Fish and Game is currently trying to optimize their use of monitoring resources for mule deer (Odocoileus hemionus) throughout Idaho. Three areas are being investigated for their potential to accomplish this goal: cost effectiveness, data utilization, and efficiency in data collection. An analysis of the cost effectiveness of monitoring methods is currently being conducted. This analysis varies the amount of each type of data available to the population model used to estimate abundance. The precision, credible interval width (CRI), associated with the estimate is used as the measure of effectiveness, mean 95% CRIs range from 9278 - 9804. This measure of precision is then combined with the cost of the collection technique to compare the cost effectiveness of different monitoring methods. Further research will focus on a weighting scheme that weights data types by both sampling precision and reliability. Thereby allowing managers to fully utilize all available data sources based on relative quality within the framework of the population model. A third line of research focuses on increasing the efficiency of monitoring effort through an alternative sampling design derived from seasonal nutrition. The previous lines of research will then be combined to solve a dynamic programming problem to determine the optimal methods for monitoring population abundance while accounting for changes in the availability of monitoring resources over space and time