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 Influences of elk browse on aspen stand structure and landbirds at the National Elk Refuge, Jackson Hole, Wyoming(Montana State University - Bozeman, Graduate School, 2015) Edwards, Jennifer Lindsay; Chairperson, Graduate Committee: Peggy Taylor.Aspen stands in the Rocky Mountains are hot spots of biodiversity meeting the habitat needs of many species, including wintering ungulates. Ungulates have the potential to alter habitat composition and structure via browsing, especially near areas of concentrated use associated with winter feedgrounds. The National Elk Refuge, established in Jackson, Wyoming in 1912, has provided supplemental winter feed for elk during all but nine winters since its establishment. I conducted the current study to assess aspen stand structure, estimate the likelihood of aspen recruitment given current browse levels, and examine if existing bird communities are reflective of aspen stand structure. I sampled 27 aspen stands at varying distances from feedgrounds during June 2014. I quantified aspen structure using five height class categories along 10 x 40 m belt transects. Twenty trees in height range of elk browse (i.e., 50-150 cm) were selected and measured within each belt to determine the Live-Dead Index, a quantification of browse intensity. I conducted two rounds of bird point counts to assess bird community composition in relation to aspen stand structure. My results indicated current browse levels were largely precluding aspen recruitment. LD Index values indicated 89% of 27 stands sampled in the National Elk Refuge were experiencing high browse intensity and aspen < or = 150 cm were being browsed back to ground level. A relationship between distance to feedgrounds and LD Index was not present, possibly resulting from intensive browsing throughout the refuge. In addition, bird communities were responding to the altered aspen stand structure. For example, Yellow Warblers were strong indicators of stands that had experienced recent aspen recruitment (i.e. greater mid-story canopy and structure). White-breasted Nuthatches were an indicator of a bird community group associated with larger aspen stands. Based on the current lack of recruitment on the refuge, large exclosures surrounding targeted aspen stands are recommended to protect juvenile aspen until they grow out of the browse zone.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 The condition of the northern winter range in Yellowstone National Park : a discussion of the controversy(Montana State University - Bozeman, 1981) Tyers, Daniel Bruce; Chairperson, Graduate Committee: J. E. (John Edgar) TaylorItem Range ecology and relations of mule deer, elk, and cattle in the Missouri River Breaks, Montana(Montana State University - Bozeman, College of Letters & Science, 1965) Mackie, Richard J.Item Responses of elk to a 500 kV transmission line on the North Boulder winter range, Montana(Montana State University - Bozeman, College of Letters & Science, 1986) Nelson, Gerald PatrickItem Elk migration patterns, and some of the factors affecting movements in the Gallatin River drainage, Montana(Montana State University - Bozeman, College of Letters & Science, 1952) Brazda, Arthur R.Item Elk use of various sized cattle exclosures(Montana State University - Bozeman, College of Agriculture, 1998) Gross, Jeffrey AlanItem Assessment of prey vulnerability through analysis of wolf movements and kill sites(Montana State University - Bozeman, College of Letters & Science, 2003) Bergman, Eric James