Browsing by Author "Proffitt, Kelly M."

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Assessing respiratory pathogen communities in bighorn sheep populations: Sampling realities, challenges, and improvements
(2017-07) Butler, Carson J.; Edwards, William H.; Jennings-Gaines, Jessica E.; Killion, Halcyon J.; Wood, Mary E.; McWhirter, Douglas E.; Paterson, J. Terrill; Proffitt, Kelly M.; Almberg, Emily S.; White, Patrick J.; Rotella, Jay J.; Garrott, Robert A.
Respiratory disease has been a persistent problem for the recovery of bighorn sheep (Ovis canadensis), but has uncertain etiology. The disease has been attributed to several bacterial pathogens including Mycoplasma ovipneumoniae and Pasteurellaceae pathogens belonging to the Mannheimia, Bibersteinia, and Pasteurella genera. We estimated detection probability for these pathogens using protocols with diagnostic tests offered by a fee-for-service laboratory and not offered by a fee-for-service laboratory. We conducted 2861 diagnostic tests on swab samples collected from 476 bighorn sheep captured across Montana and Wyoming to gain inferences regarding detection probability, pathogen prevalence, and the power of different sampling methodologies to detect pathogens in bighorn sheep populations. Estimated detection probability using fee-for-service protocols was less than 0.50 for all Pasteurellaceae and 0.73 for Mycoplasma ovipneumoniae. Non-fee-for-service Pasteurellaceae protocols had higher detection probabilities, but no single protocol increased detection probability of all Pasteurellaceae pathogens to greater than 0.50. At least one protocol resulted in an estimated detection probability of 0.80 for each pathogen except Mannheimia haemolytica, for which the highest detection probability was 0.45. In general, the power to detect Pasteurellaceae pathogens at low prevalence in populations was low unless many animals were sampled or replicate samples were collected per animal. Imperfect detection also resulted in low precision when estimating prevalence for any pathogen. Low and variable detection probabilities for respiratory pathogens using live-sampling protocols may lead to inaccurate conclusions regarding pathogen community dynamics and causes of bighorn sheep respiratory disease epizootics. We recommend that agencies collect multiples samples per animal for Pasteurellaceae detection, and one sample for Mycoplasma ovipneumoniae detection from at least 30 individuals to reliably detect both Pasteurellaceae and Mycoplasma ovipneumoniae at the population-level. Availability of PCR diagnostic tests to wildlife management agencies would improve the ability to reliably detect Pasteurellaceae in bighorn sheep populations.
Drivers of variation in the population dynamics of bighorn sheep
(Wiley, 2021-07) Paterson, J. Terrill; Proffitt, Kelly M.; Rotella, Jay; McWhirter, Douglas; Garrott, Robert
Understanding how variation in vital rates interact to shape the trajectories of populations has long been understood to be a critical component of informed management and restoration efforts. However, an expanding body of work suggests that the expectations for population dynamics of ungulates may not be applicable to small, declining, or threatened populations. Populations of bighorn sheep (Ovis canadensis) suffered declines at the turn of the 20th century, and restoration efforts have been mixed such that many populations remain small and isolated. Here, we utilized survey data collected from 1983 to 2018 from 17 populations of bighorn sheep in Montana and Wyoming to estimate the parameters of a stage-specific population model that we used to (1) characterize the spatial and temporal variation in key vital rates including whether populations were stable, increasing, or declining; (2) estimate the contributions of vital rates to variation in population growth rates; and (3) evaluate potential sources of variation in lamb survival. We found substantial variation in all vital rates both among years and populations, strong evidence for an overall decline in nine of the 17 populations, and clear evidence for multiple combinations of vital rates that resulted in positive population trajectories. The contribution of ewe survival and lamb survival to the total variation in population growth rates varied among populations; however, declines in ewe survival dominated transitions of population trajectories from stable or increasing to declining, whereas reversals of declining population trajectories were dominated by improved lamb survival. We found strong evidence for a diverse set of associations between lamb survival and environmental covariates related to growing season and winter severity. The estimated relationships predict that environmental drivers can cause important changes in lamb survival and provide suggestive evidence that the presence of Mycoplasma ovipneumoniae is not sufficient to prevent population growth. Although our work demonstrates that the trajectories of these populations of bighorn sheep are driven by a variety of processes, the diversity of relationships between vital rates and population growth rates also suggests that there are multiple pathways to manage for population recovery.
Evaluating the summer landscapes of predation risk and forage quality for elk ( Cervus canadensis )
(Wiley, 2022-08) Paterson, J. Terrill; Proffitt, Kelly M.; DeCesare, Nicholas J.; Gude, Justin A.; Hebblewhite, Mark
The recovery of carnivore populations in North American has consequences for trophic interactions and population dynamics of prey. In addition to direct effects on prey populations through killing, predators can influence prey behavior by imposing the risk of predation. The mechanisms through which patterns of space use by predators are linked to behavioral response by prey and nonconsumptive effects on prey population dynamics are poorly understood. Our goal was to characterize population- and individual-level patterns of resource selection by elk (Cervus canadensis) in response to risk of wolves (Canis lupus) and mountain lions (Puma concolor) and evaluate potential nonconsumptive effects of these behavioral patterns. We tested the hypothesis that individual elk risk-avoidance behavior during summer would result in exposure to lower-quality forage and reduced body fat and pregnancy rates. First, we evaluated individuals' second-order and third-order resource selection with a used-available sampling design. At the population level, we found evidence for a positive relationship between second- and third-order selection and forage, and an interaction between forage quality and mountain lion risk such that the relative probability of use at low mountain lion risk increased with forage quality but decreased at high risk at both orders of selection. We found no evidence of a population-level trade-off between forage quality and wolf risk. However, we found substantial among-individual heterogeneity in resource selection patterns such that population-level patterns were potentially misleading. We found no evidence that the diversity of individual resource selection patterns varied predictably with available resources, or that patterns of individual risk-related resource selection translated into biologically meaningful changes in body fat or pregnancy rates. Our work highlights the importance of evaluating individual responses to predation risk and predator hunting technique when assessing responses to predators and suggests nonconsumptive effects are not operating at a population scale in this system.
Evaluating wildlife translocations using genomics: A bighorn sheep case study
(Wiley, 2020-12) Flesch, Elizabeth P.; Graves, Tabitha A.; Thomson, Jennifer M.; Proffitt, Kelly M.; Stephenson, Thomas R.; Garrott, Robert A.
Wildlife restoration often involves translocation efforts to reintroduce species and supplement small, fragmented populations. We examined the genomic consequences of bighorn sheep (Ovis canadensis) translocations and population isolation to enhance understanding of evolutionary processes that affect population genetics and inform future restoration strategies. We conducted a population genomic analysis of 511 bighorn sheep from 17 areas, including native and reintroduced populations that received 0–10 translocations. Using the Illumina High Density Ovine array, we generated datasets of 6,155 to 33,289 single nucleotide polymorphisms and completed clustering, population tree, and kinship analyses. Our analyses determined that natural gene flow did not occur between most populations, including two pairs of native herds that had past connectivity. We synthesized genomic evidence across analyses to evaluate 24 different translocation events and detected eight successful reintroductions (i.e., lack of signal for recolonization from nearby populations) and five successful augmentations (i.e., reproductive success of translocated individuals) based on genetic similarity with the source populations. A single native population founded six of the reintroduced herds, suggesting that environmental conditions did not need to match for populations to persist following reintroduction. Augmentations consisting of 18–57 animals including males and females succeeded, whereas augmentations of two males did not result in a detectable genetic signature. Our results provide insight on genomic distinctiveness of native and reintroduced herds, information on the relative success of reintroduction and augmentation efforts and their associated attributes, and guidance to enhance genetic contribution of augmentations and reintroductions to aid in bighorn sheep restoration
Respiratory pathogens and their association with population performance in Montana and Wyoming bighorn sheep populations
(2018-11) Butler, Carson J.; Edwards, William H.; Paterson, J. Terrill; Proffitt, Kelly M.; Jennings-Gaines, Jessica E.; Killion, Halcyon J.; Wood, Mary E.; Ramsey, Jennifer M.; Almberg, Emily S.; Dewey, Sarah R.; McWhirter, Douglas E.; Courtemanch, Alyson B.; White, Patrick J.; Rotella, Jay J.; Garrott, Robert A.
At the request of National Park Service resource managers, we began a study in 2000 to evaluate causes for the decline of the bighorn sheep (Ovis canadensis) population inhabiting Bighorn Canyon National Recreation Area (BICA), the Pryor Mountain Wild Horse Range, and surrounding state and U.S. Forest Service lands in Montana and Wyoming. Our study consisted of radio-collaring adult rams and ewes with mortality sensors to monitor adult mortalities, tracking ewes to determine pregnancy and lambing rates, habitat assessments to determine why the population was not expanding into what had been modeled using GIS methodology as suitable bighorn sheep habitat, measuring ungulate herbaceous consumption rates and herbaceous production to determine plant responses, and aerial and boat surveys to determine bighorn sheep population range and population dynamics (Schoenecker and others, this report). Two habitat suitability models were created and conducted (Gudorf, this report; Wockner and others, this report) using different methodologies, and comparisons made between the two. Herd population dynamics were modeled using the POP-II and POP-III programs (Roelle, this report), and a reassessment of ungulate exclosures that were established 8–10 years ago was conducted (Gerhardt, this report). The bighorn sheep population of the greater Bighorn Canyon National Recreation Area (BICA) was extirpated in the 1800s, and then reintroduced in 1973. The herd increased to a peak population of about 211 animals (Kissell and others, 1996), but then declined sharply in 1995 and 1996. Causes for the decline were unknown. Numbers have remained around 100 ± 20 animals since 1998. Previous modeling efforts determined what areas were suitable bighorn sheep habitat (Gudorf and others, 1996). We tried to determine why sheep were not using areas that were modeled as suitable or acceptable habitat, and to evaluate population dynamics of the herd.
Restoration Potential of Bighorn Sheep in a Prairie Region
(2020-07) DeVoe, Jesse D.; Lowrey, Blake; Proffitt, Kelly M.; Garrott, Robert A.
Efforts to recover Rocky Mountain bighorn sheep (Ovis canadensis canadensis) throughout western North America have had limited success with the majority of current populations remaining in small and isolated areas on a fraction of their historical range. Prairie environments with rugged topography throughout the Northern Great Plains ecoregion were historically occupied by relatively robust bighorn sheep populations. We predicted there is likely unrealized potential habitat for restoring bighorn sheep to these areas; however, relatively little attention has been devoted to identifying habitat in unoccupied prairie regions. We used global positioning system (GPS)-collar data collected from 43 female bighorn sheep in 2 populations located in the eastern Montana, USA, portion of the Northern Great Plains during 2014–2018 to estimate a population-level annual resource selection model and identify the important factors affecting bighorn sheep resource selection. We extrapolated model predictions across eastern Montana's prairie region and identified potential habitat to understand restoration potential and assist with future translocations of bighorn sheep. Resource selection of bighorn sheep was most strongly associated with terrain slope and ruggedness, tree canopy cover, and a normalized difference vegetation index metric. Within currently unoccupied areas of the historical range, the model extrapolation predicted 7,211 km2 of habitat, with most owned and managed by private landowners (44%), Bureau of Land Management (33%), and the United States Fish and Wildlife Service (15%). Our results provide an empirical evaluation of landscape covariates influencing resource selection of bighorn sheep occupying prairie environments and provide a habitat model that may be generalizable to other areas in the Northern Great Plains ecoregion. We demonstrate substantial potential for restoration opportunities of bighorn sheep in the Northern Great Plains ecoregion. Broad restoration of bighorn sheep across the ecoregion would likely require strong collaboration among and between public resource managers, private landowners, and livestock producers given the heterogeneous land ownership patterns, management strategies, and domestic sheep distributions.
Security Areas for Elk During Archery and Rifle Hunting Seasons
(2017-07) Ranglack, Dustin H.; Proffitt, Kelly M.; Canfield, Jodie E.; Gude, Justin A.; Rotella, Jay J.; Garrott, Robert A.
Fall elk (Cervus canadensis) habitat management on public lands provides security areas for reasonable elk survival and hunter opportunity. The management focus of maintaining or improving security areas, combined with conservative harvest regulations, may explain why some elk populations have increased in the western United States. However, in areas that include lands that restrict public hunter access, elk may alter their space use patterns during the hunting season by increasing use of areas that restrict public hunter access rather than using security areas on adjacent public lands. We used global positioning system location data from 325 adult female elk in 9 southwest Montana populations to determine resource selection during the archery and rifle hunting seasons. We found that during the archery season, in order of decreasing strength of selection, elk selected for areas that restricted access to public hunters, had greater time-integrated normalized difference vegetation index values, had higher canopy cover, were farther from motorized routes, and had lower hunter effort. During the rifle season, in order of decreasing strength of selection, elk selected for areas that restricted access to public hunters, were farther from motorized routes, had higher canopy cover, and had higher hunter effort. Interactions among several covariates revealed dependencies in elk resource selection patterns. Further, cross-population analyses revealed increased elk avoidance of motorized routes with increasing hunter effort during both the archery and rifle hunting seasons. We recommend managing for areas with 13% canopy cover that are 2,760m from motorized routes, and identifying and managing for areas of high nutritional resources within these areas to create security areas on public lands during archery season. During the rifle season, we recommend managing for areas with 9% canopy cover that are 1,535m from motorized routes, and are 20.23km(2). Lastly, given increased elk avoidance of motorized routes with higher hunter effort, we recommend that to maintain elk on public lands, managers consider increasing the amount of security in areas that receive high hunter effort, or hunting seasons that limit hunter effort in areas of high motorized route densities.
Simulation-based validation of spatial capture-recapture models: A case study using mountain lions
(2019-04) Paterson, J. Terrill; Proffitt, Kelly M.; Jimenez, Ben; Rotella, Jay J.; Garrott, Robert A.
Spatial capture-recapture (SCR) models have improved the ability to estimate densities of rare and elusive animals. However, SCR models have seldom been validated even as model formulations diversify and expand to incorporate new sampling methods and/or additional sources of information on model parameters. Information on the relationship between encounter probabilities, sources of additional information, and the reliability of density estimates, is rare but crucial to assessing reliability of SCR-based estimates. We used a simulation-based approach that incorporated prior empirical work to assess the accuracy and precision of density estimates from SCR models using spatially unstructured sampling. To assess the consequences of sparse data and potential sources of bias, we simulated data under six scenarios corresponding to three different levels of search effort and two levels of correlation between search effort and animal density. We then estimated density for each scenario using four models that included increasing amounts of information from harvested individuals and telemetry to evaluate the impact of additional sources of information. Model results were sensitive to the quantity of available information: density estimates based on low search effort were biased high and imprecise, whereas estimates based on high search effort were unbiased and precise. A correlation between search effort and animal density resulted in a positive bias in density estimates, though the bias decreased with increasingly informative datasets. Adding information from harvested individuals and telemetered individuals improved density estimates based on low and moderate effort but had negligible impact for datasets resulting from high effort. We demonstrated that density estimates from SCR models using spatially unstructured sampling are reliable when sufficient information is provided. Accurate density estimates can result if empirical-based simulations such as those presented here are used to develop study designs with appropriate amounts of effort and information sources.