Theses and Dissertations at Montana State University (MSU)
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Item Spatiotemporal covariates, individual characteristics, and mountain lion harvest as potential sources of variation in elk calf survival(Montana State University - Bozeman, College of Letters & Science, 2019) Forzley, Michael James; Chairperson, Graduate Committee: Jay J. RotellaTo understand the efficacy of increasing the harvest of large carnivores for increasing elk calf survival, we compared calf survival data collected from two elk herds before, during, and after a mountain lion harvest treatment which consisted of increases in prescribed mountain lion harvest quotas. We collected survival data from 534 radio-tagged elk calves in both the East Fork and West Fork herds of the upper Bitterroot Valley of west-central Montana. We used these data and time-to-event analyses to estimate the annual rates of survival and cause-specific mortality for elk calves in the study, as well as estimate the relationships between elk calf survival and several factors previously related to variation in annual elk calf survival. Average annual rates of survival for female calves before the mountain lion harvest treatment (pre-treatment era) were 0.38 (95% CI = 0.00-0.54) in the West Fork herd, and 0.37 (95% CI = 0.09-0.65) in the East Fork herd. Annual rates of survival for female calves during the harvest treatment (during-treatment era) were 0.65 (95% CI = 0.47-0.83) in the West Fork herd and 0.65 (95% CI = 0.46-0.87) in the East Fork herd. Annual rates of survival for female calves 4-5 years post-harvest treatment (post-treatment era) were 0.46 (95% CI = 0.31-0.61) in the West Fork herd and 0.47 (95% CI = 0.32-0.62) in the East Fork herd. Survival of male calves followed a similar pattern. Rates of mountain lion predation were highest in the pre-treatment era, moderate in the during-treatment era, and lowest in the post-treatment era. However, decreased rates of mountain lion predation following mountain lion harvest treatment coincided with increased probability of non-predation related mortality, and short-term changes in annual elk calf survival. Our results suggest that mountain lion harvest management prescriptions designed to achieve moderate, short-term reductions in mountain lion population abundance may be effective in allowing for short-term increases in elk calf recruitment and may be an effective management tool to increase calf recruitment.Item Effects of mountain pine beetle on elk habitat and nutrition in the Elkhorn Mountains of Montana(Montana State University - Bozeman, College of Letters & Science, 2018) Cascaddan, Brent Morris; Chairperson, Graduate Committee: Robert A. GarrottMountain pine beetle (Dendroctonus ponderosae, MPB) outbreaks have become increasingly prevalent in western North America, resulting in ecological changes in pine forests that have important implications for wildlife populations and habitat. The potential effects of MPB-caused tree mortality on ungulate populations and habitat are relatively unstudied, and the possibility exists for both beneficial changes to ungulate habitat such as increased production of forage (i.e., forage availability) through the opening of the forest canopy and negative impacts such as accelerated phenology of herbaceous plants that may reduce forage quality. Using data collected during 2015 - 2017 in MPB-impacted National Forests in west-central Montana, I quantified the effects of MPB outbreaks on elk summer forage resources and use. To accomplish this objective, I 1) evaluated differences in herbaceous plant communities between mature uninfested lodgepole pine stands and two temporal classes of MPB-impacted forest stands (i.e., lodgepole pine cover classes: mature uninfested, old infested: > or = 10 years old, recent infested: <10 years old), 2) evaluated differences in elk summer forage availability and herbaceous vegetation quality, and 3) compared current elk use of lodgepole cover classes (2015 - 2017) to a previous elk telemetry study conducted during 1980 - 1991 before the MPB epidemic. I found that herbaceous forage plant communities did not differ in plant species composition but did differ in forage abundance in each cover class. Forage abundance was significantly different between cover classes and was highest in the old-infested cover class, and lowest in the mature uninfested cover class. The dominant phenology stage of forage species did not change across cover classes by a biologically meaningful amount, but herbaceous quality differed across cover classes, however the amount of difference was small. During the 2015 - 2017 study, elk used all three lodgepole pine cover classes in proportion to how much of each cover class was available. Elk use of lodgepole pine during the 1980 - 1991 study was approximately double what was estimated to be available and suggests elk are using the beetle-killed forest less than prior to infestation. My results indicate MPB does not negatively affect elk nutrition during later summer (July and August), and active management of beetle-killed forest is not necessary for the benefit of elk during this time period, but may be needed for improving elk habitat in other ways during other times of year.Item Spatiotemporal variation in grassland biomass and quality across the upper Yellowstone River basin : variation across phenology and land use gradients and validation of remote sensing vegetation indices(Montana State University - Bozeman, College of Letters & Science, 2016) Garroutte, Erica Lynn; Chairperson, Graduate Committee: Andrew J. HansenSpatial and temporal heterogeneity in forage biomass and quality is known to play an integral role in the movement and population dynamics of migratory ungulates. Once limited by field-based forage assessments, the Normalized Difference Vegetation Index (NDVI) and the Enhanced Vegetation Index (EVI) have gained considerable attention as proxies for landscape-scale forage biomass and quality at fine temporal scales. In the Greater Yellowstone Ecosystem (GYE), these indices have become especially important for understanding how potential advances in the timing of spring green-up due to climate change and human land use may be influencing the forage patterns available to migratory elk (Cervus elaphus). Given this concern, more information is needed on how the forage biomass and quality available to elk varies across elevation-related phenology and land use gradients and on the reliability of using NDVI and EVI to map forage patterns across the GYE. Using 250m2 MODIS NDVI and EVI and field estimates of grassland biomass and quality, we examined how the rate and magnitude of seasonal variation in forage biomass and quality differed across elevation-related phenology and land use gradients, assessed how the accuracy of NDVI and EVI as proxies for forage biomass and quality differed across the landscape, and then mapped spatiotemporal variation in the abundance of high quality forage for elk across the Upper Yellowstone River Basin (UYRB). We found that: (1) Grasslands with late onset of growth and irrigated agriculture had a faster rate of growth and a greater seasonal magnitude of biomass and quality for elk than all other grasslands; (2) 250m2 NDVI and EVI explained minimal variation in grassland biomass and quality across the UYRB; and (3) the accuracy of NDVI and EVI differed across elevation-related phenology and land use gradients in the UYRB. These results provide novel information on the rate and magnitude of seasonal variation in forage biomass and quality and on the reliability of using NDVI and EVI to map the forage patterns available to migratory elk.Item Infectivity and immunogenic capability of Dictyocaulus species from elk and cattle in experimentally infected bovine calves(Montana State University - Bozeman, College of Agriculture, 1968) Presidente, Paul Joseph AlvinItem Behavior and environmental selection by elk (Cervus canadensis nelsoni) during summer and fall in the first and second Yellow Mule drainages, Madison County, Montana(Montana State University - Bozeman, College of Agriculture, 1975) Joslin, Gayle LynneItem Gradients of predation risk affect distribution and migration of a large herbivore(Montana State University - Bozeman, College of Letters & Science, 2007) Grigg, Jamin Lyle; Chairperson, Graduate Committee: Robert A. GarrottFew studies have placed wildlife behavioral responses to human disturbance and hunting pressure within the larger ecological context of predator-prey theory. Given that large herbivores respond behaviorally to the presence of wolves and other predators, we should expect similar adaptive behavioral responses when large herbivores are presented with risk in the form of human disturbance and hunting pressure. One index of human access, disturbance, and thus potential predation risk to large herbivores from hunters are road and trail networks bisecting large herbivore ranges. I evaluated the effects of human disturbance and predation pressure in the forms of motorized and total combined access networks on elk (Cervus elaphus) summer home range size, timing of fall migration, and movement rates by placing 49 GPS radio-collars on adult female elk on a winter range in the Madison Valley, MT over the course of a two-year study. I found evidence that elk responded to motorized access during the summer by increasing summer home range size.Item The effects of supplemental feeding on stress hormone concentrations in elk(Montana State University - Bozeman, College of Letters & Science, 2009) Patrek, Victoria Elizabeth; Chairperson, Graduate Committee: Scott Creel; Paul Cross (co-chair)On twenty-two feedgrounds in western Wyoming, elk (Cervus elaphus) are provided with supplemental feed throughout the winter. Brucellosis seroprevalence of feedground elk is 26% whereas other elk in the Greater Yellowstone Ecosystem have historically had a brucellosis seroprevalence of 2-3%. The aggregation of elk during peak transmission allows brucellosis to persist in the feedground populations. In addition to creating the opportunity for disease transmission, the aggregation of elk on feedgrounds may have detrimental physiological effects. Studies have shown that chronically high stress hormone concentrations can suppress the immune system and lead to increased disease susceptibility. Potential stressors on the feedgrounds include high densities, large group sizes and aggressive social interactions. In this study I investigated how factors associated with supplemental feeding affect stress hormone levels, as indexed by fecal glucocorticoid levels, in elk on feedgrounds and elk on native winter range. I also worked with managers to experimentally alter the feeding distribution on the feedgrounds to examine how feeding density affects stress hormone levels and aggression rates. Results show that elk on feedgrounds have stress hormone levels 31% higher than elk on native winter range (Welch's t₂₇.₂₃=2.39, p=0.024). Experimental reduction of feed density did not have an effect on stress hormone level or aggression rates. But note the relationship between fGCs and local densities here. Although the feeding treatments did appear to reduce local feeding densities,s this effect was not significant and was small relative to the large differences in density among sites. Regardless as to the cause of the high stress hormone levels seen in supplementally fed elk, the feedgrounds are creating an epidemiological setting for disease transmission and a physiological state that may increase susceptibility to disease. The impact of these stress hormone concentrations on disease susceptibility remains unknown, but may be an important driver of disease dynamics in these elk populations.Item Evaluating aspen responses to changes in elk abundance, distribution and behavior following wolf reestablishment in West-Central Yellowstone National Park(Montana State University - Bozeman, College of Letters & Science, 2011) Shafer, Timothy Lee; Chairperson, Graduate Committee: David RobertsThe reintroduction of wolves to Yellowstone National Park (YNP) in the mid-1990's has created a unique natural experiment for the investigation of trophic cascades operating at large spatial scales and involving large terrestrial mammals. Wolves have been directly linked to changes in elk density/behavior and have been hypothesized to be the driving force behind observed changes in woody plant growth in the system. The primary objectives of this study were to investigate the occurrence of a trophic cascade among wolves, elk and aspen in an area of YNP where elk abundance and distribution changed dramatically as a direct result of wolf reestablishment in the system. In Chapter 2, I determined the distribution and demographic characteristics of aspen in the Madison headwaters study area (MHSA) and identified the environmental attributes associated with its distribution on the landscape. Additionally, I evaluated the morphology, productivity, and persistence of aspen in both clonal and seedling-established. In Chapter 3, I established a climate-growth relationship for aspen to investigate the occurrence of a shift in productivity related to climate coincident with the timing of wolf reestablishment. I used standard dendrochronology techniques to investigate growth trends and identified which climate variables are most important to aspen productivity in this region. Additionally, I established the timing of historic aspen recruitment in the MHSA using age of mature trees. In Chapter 4, I investigated a trophic cascade among wolves, elk and aspen. I reconstructed historical browse conditions for aspen to look for a shift in browse regimes that occurred concurrently with the changes in elk abundance/distribution by performing a dendrochronological analysis of aspen architectural morphology. I also evaluated plant height, productivity, and longevity of aspen where elk densities had declined dramatically in order to capture the expected growth response. I used ANOVA's and multiple comparison procedures to evaluate browse conditions and aspen growth among sites where elk densities have declined dramatically and those where elk densities have remained relatively constant.Item Applying risk allocation theory in a large mammal predator-prey system : elk-wolf behavioral interactions(Montana State University - Bozeman, College of Letters & Science, 2004) Gude, Justin Albert; Chairperson, Graduate Committee: Robert A. Garrott; Scott Creel (co-chair)Understanding the behaviorally-mediated indirect effects of predators in ecosystems requires knowledge of predator-prey behavioral interactions, and the risk allocation hypothesis can be used to make predictions about such interactions. In predator-ungulate-plant systems, empirical research quantifying how predators affect ungulate group sizes and distribution, in the context of other influential variables, is particularly needed. We determined non-predation variables that affect elk (Cervus elaphus) group sizes and distribution on a winter range in the Greater Yellowstone Ecosystem (GYE), using regression analyses of 1219 elk groups counted and mapped over 12 years prior to wolf (Canis lupus) recolonization. We next examined the relevance of these non-wolf-predation variables in the presence of wolves using logistic and linear regression on surveys of 513 1-km2 areas conducted over 2 years. Using model selection techniques, we evaluated risk allocation and other a priori hypotheses of elk group size and distributional responses to wolf predation risk while accounting for influential nonwolf- predation variables. We found little evidence that wolves affect elk group sizes, which were strongly influenced by habitat type. Following predictions from the risk allocation hypothesis, wolves likely created a more dynamic elk distribution in areas that they frequently hunted, as elk tended to move during the period of safety following wolf encounters in those areas. We predict that this distributional response to wolf predation risk should decrease the spatial heterogeneity of elk impacts on grasslands in areas that wolves frequently hunt. We also predict that this response should decrease browsing pressure on heavily-browsed woody plant stands in certain areas, which is supported by recent research in the GYE. This research highlights the importance of predator-prey behavioral interactions in large mammal systems.Item Validating alternative methods of modeling wildlife corridors using relocation data from migrating elk and dispersing wolverines(Montana State University - Bozeman, College of Letters & Science, 2012) Rainey, Meredith McClure; Chairperson, Graduate Committee: Andrew J. Hansen; Andrew J. Hansen was a co-author of the article, 'What is the current state of our ability to model wildlife corridors? An overview of the development, application, and validation of connectivity models' submitted to the journal 'Conservation biology' which is contained within this thesis.; Andrew J. Hansen was a co-author of the article, 'A test of the ability of connectivity models to predict migration movements using GPS collar data from migrating elk' submitted to the journal 'Journal of wildlife management' which is contained within this thesis.; Andrew J. Hansen and Robert M. Inman were co-authors of the article, 'A test of the ability of connectivity models to predict dispersal movements using relocation data from dispersing wolverines' submitted to the journal 'Journal of wildlife management' which is contained within this thesis.; Andrew J. Hansen was a co-author of the article, 'Assessing the sensitivity of connectivity models to model parameterization' submitted to the journal 'Landscape ecology' which is contained within this thesis.Habitat loss and fragmentation increasingly impede wildlife movements that are essential for the long-term persistence of populations. Wildlife corridors facilitating movement have become a key component of conservation planning as a result. Models are increasingly used to identify likely corridors, but predictions are rarely validated against empirical data, resulting in uncertainty in whether corridors function as intended. This study asks: 1) What is the current state of our ability to predict corridors?, 2) How well do the most common models predict wildlife movement?, 3) Which method performs best?, and 4) How sensitive are models to parameterization decisions? I addressed these questions by synthesizing the corridor modeling literature, modeling migration paths of elk and dispersal paths of wolverines using the two most common corridor models (cost-distance and circuit theory models), validating predicted corridors against relocation data, and analyzing model sensitivity to parameterization. An additional question, 5) What drives habitat selection during long-distance migration and dispersal movements?, is also explored through these analyses. Key findings include: 1) Corridor modeling has progressed enormously in recent years, but model validation has been rare, 2) Corridor models are capable of offering valuable information, but their utility depends on conservation objectives, 3) Relative model performance depends on the match between model assumptions and focal species movement ecology, 4) Both models have similar sensitivity to model parameters, but spatial patterns of sensitivity are unpredictable for circuit theory models, and 5) The drivers of habitat selection during long-distance movements may be similar to those of primary habitat selection, but further research is needed. These studies constitute the most rigorous, comprehensive effort to validate corridor model predictions to date. They are expected to offer guidance for conservation scientists and practitioners as to reasonable expectations for corridor model performance, the importance of selecting methods appropriate to species movement ecology, and which decisions in the modeling process matter most. This work also highlights the need for further collection of data suitable for model validation, broader comparison of corridor models across diverse species and landscapes, and continued study of the ecology of long-distance movements.