Theses and Dissertations at Montana State University (MSU)
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Item Spatial ecology of mountain ungulates in the northern Rocky Mountains: range expansion, habitat characteristics, niche overlap, and migratory diversity(Montana State University - Bozeman, College of Letters & Science, 2018) Lowrey, Blake Henson; Chairperson, Graduate Committee: Robert A. Garrott; Robert A. Garrott, Hollie M. Miyasaki, Gary Fralick and Sarah R. Dewey were co-authors of the article, 'Seasonal resource selection by introduced mountain goats in the southwest greater Yellowstone area' in the journal 'Ecosphere' which is contained within this thesis.; Robert A. Garrott, Doug E. McWhirter, P.J. White, Nicholas J. DeCesare and Shawn T. Stewart were co-authors of the article, 'Niche similarities among introduced and native mountain ungulates' in the journal 'Ecological applications' which is contained within this thesis.; Kelly M. Proffitt, Douglas E. McWhirter, P. J. White, Alyson B. Courtemanch, Sarah R. Dewey, Hollie M. Miyasaki, Kevin L. Monteith, Julie S. Mao, Jamin L. Grigg, Carson J. Butler, Ethan S. Lula and Robert A. Garrott were co-authors of the article, 'Contrasting seasonal movements in native and restored populations: a case for conserving migratory portfolios' submitted to the journal 'Journal of applied ecology' which is contained within this thesis.; Douglas E. McWhirter, Kelly M. Proffitt, Alyson B. Courtemanch, Kevin L. Monteith, P. J. White, J. Terrill Paterson, Sarah R. Dewey and Robert A. Garrott were co-authors of the article, 'Individual variation creates diverse portfolios of seasonal movement patterns and ranges in a migratory ungulate' submitted to the journal 'Ecology' which is contained within this thesis.Mountain ungulates, although recognized as iconic and charismatic wildlife species, are the least studied and understood large mammals in western North America. The paucity of data, specifically concerning spatial ecology, presents a formidable challenge to regional wildlife managers tasked with the responsibility of managing populations with limited empirical studies on which to base decisions. We used GPS data collected from bighorn sheep (Ovis canadensis) and mountain goats (Oreamnos americanus) sampled from multiple populations throughout the northern Rocky Mountains to develop comparative studies characterizing seasonal habitats and potential range expansion of introduced mountain goats, niche overlap with native bighorn sheep, and migratory diversity of restored, augmented, and native bighorn sheep. Slope was the dominant predictor of mountain goat habitat use in both seasons, although mountain goats selected for steeper slopes in winter than in summer. Regional extrapolations depicted suitable mountain goat habitat in the Snake River, Teton, Gros Ventre, Wyoming and Salt Ranges centered around steep and rugged areas. Although bighorn sheep occurred on steeper slopes than mountain goats in summer and mountain goats occurred on steeper slopes in winter, we observed broad niche overlap according to season-species niche models and observed GPS locations where the two species were sympatric. In native bighorn sheep herds, we observed longer migrations on average and significantly more variation among individuals when compared to restored herds. The enhanced individual variation in native herds resulted in diverse portfolios of migratory behaviors and ranges, including newly documented high elevation long-distance migrants, increased switching rates between migratory behaviors, and sub-populations that were diffusely spread across both summer and winter ranges. In contrast, restored herds had limited individual variation, were largely non-migratory, had less switching between years, and were generally concentrated on both summer and winter ranges. In addition to increasing the abundance and distribution of bighorn sheep on the landscape, we suggest there may be value in simultaneously increasing the diversity of seasonal movement strategies, and in so doing, building resilience to future perturbations and disease, and mirroring the movement portfolios observed in native populations of bighorn sheep.Item Niche character in a temporally varying environment(Montana State University - Bozeman, College of Letters & Science, 2014) Nowack, Shane Patrick; Chairperson, Graduate Committee: Isaac Klapper; Isaac Klapper and David M. Ward were co-authors of the article, 'Consequences of temporal frequency regime on optimal behavior' submitted to the journal 'Journal of theoretical biology' which is contained within this thesis.; Millie T. Olsen, Eric D. Becraft, Donald A. Bryant, and David M. Ward were co-authors of the article, 'Evidence of closely related Synechococcus species inhabiting the microbial mats of Mushroom Spring, Yellowstone National Park' submitted to the journal 'Applied and environmental microbiology' which is contained within this thesis.One of the major goals in the field of ecology is to understand the connection between an organism and its environment. In this thesis both theoretical and empirical approaches were used to investigate the effects of environmental variation on niche structure. A mathematical model was developed to make predictions about the consequences of temporal frequency regime on optimal behavior. Three different time scales of environmental variation were studied: faster than the growth rate, slower than growth rate, and similar to growth rate. The model results predicted that (i) optimal behavior appears to be independent of fast environmental variation, (ii) niche width is largely determined by slow environmental variation, and (iii) biological clocks may have evolved from environmental variations that occur with a frequency that is comparable to the growth rate of the organism. Representatives of the predominant organisms inhabiting the microbial mats found in the effluent channels of Mushroom Spring, Yellowstone National Park, were cultivated, and the growth rates of the isolated strains were measured with respect to light, temperature, and availability of dissolved inorganic carbon. The growth rate measurements suggested that closely-related Synechococcus species with distinct ecological adaptations exist within the Mushroom Spring community, and may explain the genetic diversity found in situ. The results also suggested that the fundamental light niche is interconnected with other environmental parameters, such as temperature and dissolved inorganic carbon availability. To compare the results of the mathematical and microbiological approaches, environmental light data that were collected in the vicinity of Mushroom Spring were incorporated into the mathematical model. The optimal fundamental light niche that was predicted by the model and the measured light niche of one of the cultivated strains exhibited qualitative similarities. Collectively, this interdisciplinary approach has led to the identification of several environmental characteristics that are hypothesized to be important in determining niche structure.