Theses and Dissertations at Montana State University (MSU)
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Item Ecosystem pioneers: beaver dispersal and settlement site selection in the context of habitat restoration(Montana State University - Bozeman, College of Agriculture, 2018) Ritter, Torrey Daniel; Chairperson, Graduate Committee: Lance McNewThe activities of beavers (Castor canadensis) provide a variety of benefits to stream systems by capturing and storing water and sediment, expanding riparian areas, and increasing habitat heterogeneity. Understandably, land and wildlife managers are interested in using beavers as a habitat restoration tool. However, streams targeted for restoration are often degraded and lack recent beaver activity, and therefore represent suboptimal habitat. The habitat selection process for beavers in suboptimal and unmodified habitats provides a natural analogue to beaver restoration, but the process is not well-understood. I radio-marked juvenile beavers and conducted beaver-use surveys in tributary streams of the Gallatin and Madison River drainages in southwest Montana to investigate dispersal, survival, and settlement site selection by beavers colonizing novel areas. My objective was to study beaver ecology in the context of beaver restoration to improve identification of suitable project locations. Beaver colony densities in the study area were low or average, though colony densities in suitable habitat were generally high. There was evidence of delayed dispersal, and as the density of active beaver colonies increased the probability of dispersal decreased. Radio-marked beavers that dispersed settled quickly and dispersal distances were highly variable. Most beavers settled in active colonies or other beaver-modified habitats, and colonization of unmodified stream segments was rare. My top habitat selection models indicated new settlement sites were located in stream segments characterized by low gradients, dense woody riparian vegetation close to the stream, and relatively narrow stream channels. Stream channels at new settlement sites were more variable both in cross-sectional and longitudinal depth and were more heavily influenced by secondary channels than unsettled sites. My results suggest beavers select for pre-engineered habitat over unoccupied stream segments, and in novel areas habitat conditions that facilitate stable dam construction appear most important. When choosing project locations, restoration practitioners should consider local beaver colony locations and densities to assess the potential for dispersers to reach the restoration site. Stream segments that provide dam resiliency and hiding cover should be targeted for initial restoration efforts, and pre-engineering of habitat prior to beaver occupancy may increase the probability of successful colony establishment.Item Effects of climate on ground squirrel species distribution(Montana State University - Bozeman, College of Letters & Science, 1997) Kociolek, Angela VictoriaItem Effects of fire on avian distributions and patterns of abundance over two vegetation types in southwest Montana : implications for managing fire for biodiversity(Montana State University - Bozeman, College of Letters & Science, 1997) Henderson, Steven J.Item Responses of steppe plants to gradients of water soil texture and disturbance in Montana, U.S.A.(Montana State University - Bozeman, College of Letters & Science, 1990) Harvey, Stephen JohnItem Investigating the role of dispersal on the genetic structure of wild populations(Montana State University - Bozeman, College of Letters & Science, 2014) Powell, John Henry, III; Chairperson, Graduate Committee: Steven Kalinowski; Steven T. Kalinowski, Mark L. Taper, Jay J. Rotella, and R. A. Garrott were co-authors of the article, 'Estimating inbreeding depression in a non-pedigreed population of Weddell seals Leptonychotes weddellii' submitted to the journal 'Evolution' which is contained within this thesis.; Steven T. Kalinowski, Megan D. Higgs, Michael R. Ebinger, Ninh V. Vu, and Paul C. Cross were co-authors of the article, 'Microsatellites indicate minimal barriers to mule deer Odocoileus hemionus dispersal across Montana, USA' in the journal 'Wildlife biology' which is contained within this thesis.; Steven T. Kalinowski, Megan D. Higgs, and Clint C. Muhlfeld were co-authors of the article, 'Hybridization did not appear to increase dispersal in a westslope cutthroat trout Oncorhynchus clarkii lewisi metapopulation' submitted to the journal 'Canadian journal of fisheries and aquatic sciences' which is contained within this thesis.The movement of individuals among populations (dispersal) is an ecological process that can affect the genes of populations. Identifying the role this process plays in the wild can be difficult due to uncertainty caused by other genetic and ecological processes. Here, I present three studies investigating the role of dispersal in wild populations of Weddell seals (Leptonychotes weddellii), mule deer (Odocoileus hemionus) and westslope cutthroat trout (Oncorhynchus clarkii lewisi). Each of these studies presents, to my knowledge, novel statistical approaches within this discipline that account for the uncertainty caused by other genetic and ecological processes when investigating the role of dispersal. In the second chapter I present a study that uses a two-step maximum likelihood analysis, fit with the data cloning algorithm, to incorporate uncertainty in estimating the probability that an individual has multiple copies of the same gene from a given ancestor into estimates of the association between this probability and the number of pups a female Weddell seal will produce in her life. This study did not find strong support for the hypothesis that increased similarity of an individual's genes reduced the number of pups she would produce across her lifetime. In the third chapter I use individual based genetic distance measures to investigate the association between features of the landscape and the genetic similarity of mule deer. This study found no detectable barriers to dispersal of mule deer across Montana. The fourth chapter presents a study comparing the dispersal rate between samples of westslope cutthroat trout from Glacier National Park that have interbred with introduced rainbow trout (Oncorhynchus mykiss) to samples that have not. There was no detectable difference in the dispersal rate of westslope cutthroat trout that have interbred with introduced rainbow trout relative to those that have not. In conclusion, dispersal is an important ecological process affecting the genes of populations, but understanding the role it plays across a landscape requires adequately accounting for the uncertainty due to other genetic and ecological processes. The three studies presented highlight different ways of addressing this problem when investigating the role of dispersal in the wild.Item The spatial ecology and mating system of black bears (Urus americanus) in New Mexico(Montana State University - Bozeman, College of Letters & Science, 2008) Costello, Cecily Marie; Chairperson, Graduate Committee: Scott CreelIn summary, our results show that high rates of male dispersal and female philopatry combine to create a spatial genetic structure that generates low rates of inbreeding and little need for kin discrimination among potential mates. Thus, evidence supports the hypothesis that inbreeding avoidance is achieved by means of male-biased dispersal in black bears. Our results also suggest the general pattern of male-biased dispersal is modified by competition for mates or resources.