Theses and Dissertations at Montana State University (MSU)
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Item Food resources for grizzly bears at army cutworm moth aggregation sites in the Greater Yellowstone Ecosystem(Montana State University - Bozeman, College of Agriculture, 2022) Lozano, Katerina N.; Chairperson, Graduate Committee: Robert K. D. Peterson; This is a manuscript style paper that includes co-authored chapters.Army cutworm moths (Euxoa auxiliaris) (ACM) migrate annually to peaks on the eastern edge of the Greater Yellowstone Ecosystem (GYE). Grizzly bears (Ursus arctos horribilis) feed on these moths from mid-to late summer. The Shoshone Forest is preparing a management plan to address the conservation of these sites and foraging bears. Increased human use and GYE-wide changes in grizzly bear food availability and related foraging patterns are concerns prompting plan preparation. This study addresses grizzly bear diet and vegetation foraging locations on a prominent moth site ('South Site'). A 1991 study identified 4 forb genera utilized by bears at ACM sites. A 2017-2018 study identified 5 more and postulated that biscuitroot (Lomatium spp.), found in high elevation meadows, was an important resource for grizzly bears. During 2020-2021 we clarified these findings using scat collection and descriptions of available vegetation. We determined the frequency and volume of food items in 298 scats. We quantified vegetation at peak meadows (elevation: 3,078 - 3,657-m) and in cirque basins (elevation: 3,658 - 3,931-m) to record the percent cover of nine forb genera. We also described the density of biscuitroot and craters where bears excavated roots to determine if biscuitroot influences foraging site choices for grizzly bears. We confirmed use of 7 of the 9 previously identified forb genera. The most frequently consumed foods by grizzly bears were ACM (23% volume) and roots and tubers (38% volume). Similarly, the 2017-2018 study found 20% ACM by volume and 45% roots and tubers by volume. There was a positive, linear relationship between the density of flowering biscuitroot and craters from grizzlies digging roots in several peak meadows (p < 0.001). Rather than foraging solely on ACMs, grizzly bears on this moth site relied highly on vegetation in their diet, specifically roots and tubers from biscuitroot and clover. Our findings suggest grizzly bears have a diverse diet at this moth site that may allow them to adjust to variations in ACM abundance. They focused foraging on roots and tubers at 5 peak meadows near talus where moth foraging occurs; information that can potentially help mitigate human-grizzly bear interactions involving climbers.Item Evaluating bear management areas in Yellowstone National Park(Montana State University - Bozeman, College of Letters & Science, 2022) Loggers, Elise Ahlenslager; Chairperson, Graduate Committee: Andrea Litt; This is a manuscript style paper that includes co-authored chapters.A growing body of research suggests large predators change their behavior near humans in ways that parallel how prey respond to predators; when outdoor recreation increases, avoiding humans becomes more difficult. Restricting human access to reduce detrimental effects of human-wildlife interactions can be an attractive management tool, however, rarely is the efficacy of such measures assessed. In 1982, Yellowstone National Park began instituting short-term, annual restrictions to areas of the backcountry containing important food resources for grizzly bears (Ursus arctos). These areas -- Bear Management Areas (BMAs) -- were intended to reduce human-caused disturbance of foraging bears and improve visitor safety. We sought to assess whether grizzly bears: 1) preferred BMAs with access restrictions more than other areas in YNP and 2) changed their response to sporadic (trail) and predictable (campsite) recreation sites depending on BMA access restrictions. We modeled resource selection of grizzly bears with step-selection functions, based on GPS locations from male and female bears collected from 2000 to 2020. Our analyses demonstrated that grizzly bears differentially selected BMAs, compared to areas outside BMAs, and that selection changed with sex and season. Bears likely prefer BMAs for the resources they contain more than to avoid people as only males changed their selection of BMAs based on access restrictions. Males avoided hiking trails during the day, but preferred trails at night. Females changed their selection of trails depending on human access restrictions and avoided trails in unrestricted BMAs. Combined with previous work, results suggest bears capitalize on the environment to avoid human presence, often with sex-specific strategies. For sporadic recreation, males temporally avoid the perceived risk of people whereas females spatially avoid the perceived risk of people. Although lower-intensity activities often are thought of as compatible with conservation, such recreation may be cryptic, but important, drivers of behavioral change in wildlife.Item Grizzly bears and humans at two moth aggregation sites in Wyoming(Montana State University - Bozeman, College of Agriculture, 2020) Nunlist, Erika Ana; Chairperson, Graduate Committee: Bok SowellHuman interactions with grizzly bears at moth sites is an important management issue because of the potential for displacing bears and the implications for human safety. The objective of our study was to quantify human and bear use overlap and interactions associated with two of the most human-accessible moth sites in the Greater Yellowstone Ecosystem. Our field work was conducted during the summers of 2017 and 2018. We conducted systematic bear surveys and analyzed the data using a resource selection function. Human use was quantified through trailhead monitoring, peak log entries, and opportunistic documentation. Hiking route data were collected using GPS tracking units distributed at trailheads. Human-bear overlap was assessed by comparing human and bear use and validated against interaction location data. We conducted 293 surveys and documented 266 bear locations. Landscape covariates describing temperature, moisture, terrain, and landcover were important to grizzly bear use. We recorded very different human use levels between the two study sites (North site: 3 groups/year; South site: 35 groups/year). Human use at the North site was dispersed and associated with hunting and use at the South site was most often associated with peak climbing and/or bear viewing and was concentrated along one primary route to the peak. We documented a total of 43 interactions (at the South site only) and obtained location data for 29 of those interactions. During human-bear interactions, bears strongly avoided human presence 80% of the time and had no apparent reaction 20% of the time. Most interactions occurred immediately around the South site peak (14/29) or along the primary route (12/29), areas that we identified to have high human and bear use overlap. We confirmed significant human safety and bear disturbance management concerns. Human safety concerns were most apparent in uneducated, and consequently unprepared, mountain climbing groups with small groups sizes (<4 people, n=64/70). Bear disturbance concerns were apparent from numerous interactions that resulted in bear displacement. Overall, we suggest that the concern expressed by managers over human and bear use overlap at the South site is warranted. Mitigation efforts should be explained in a management plan.Item Livestock depredation by grizzly bears on Forest Service grazing allotments in the Greater Yellowstone Ecosystem(Montana State University - Bozeman, College of Agriculture, 2017) Wells, Smith Laura; Chairperson, Graduate Committee: Lance McNewGrizzly bear population growth and range expansion over the last several decades in the Greater Yellowstone Ecosystem (GYE) has led to increased human-bear conflicts, including livestock depredation on public land grazing allotments. A better understanding of patterns and relationships between grazing allotment management and grizzly bear depredation of livestock is needed for adaptive, sustainable management in the ecosystem. Historic U.S. Forest Service and National Park Service livestock grazing records, grizzly bear habitat attributes, and documented livestock depredations by grizzly bears were collated for 316 public land grazing allotments within the grizzly bear Demographic Monitoring Area (DMA) during 1992-2014. Spatio-temporal relationships between annual livestock depredation counts and grazing allotment characteristics were modeled for each allotment during the study period at two spatial extents, representing daily and annual grizzly bear activity areas. As the Yellowstone grizzly population expanded during the last several decades, more public land grazing allotments were exposed to potential livestock-grizzly bear interactions and results indicated that both livestock stocking and grizzly bear habitat characteristics in and around allotments were related to documented depredations during 1992-2014. Annual numbers of livestock and grizzly bear density on allotments had a large, positive effect on average livestock depredation event counts. Allotment size and summer grazing both were related to higher depredation event counts while the presence of bulls and/or horses was related to lower counts. Allotments with less rugged terrain, lower road density, relatively higher vegetative primary productivity, greater amounts of whitebark pine, and further from forest edge on average were associated with higher average livestock depredation event counts. Managers and livestock producers could use these results to support adaptive management approaches and long-term planning such as increasing herd supervision, especially in areas with quality grizzly bear habitat and high grizzly bear density, or altering grazing management strategies and grazing locations to limit potential livestock depredation events. Results provide insight into historic livestock-grizzly bear conflicts on public lands in a large, complex ecosystem and although challenging, results could support cooperative management strategies to sustain the grizzly bear population and livestock operations in the GYE.Item Permeability of three-strand electric fences by black bears and grizzly bears(Montana State University - Bozeman, College of Agriculture, 2018) Johnson, Brittani Justine; Chairperson, Graduate Committee: Lance McNewElectric fencing has been used to deter bears in North America for several decades. Producers have turned to a design of a minimum of five-wire electric fence as their primary solution to reduce livestock depredation and to reduce raids of chicken houses and beeyards. However, these designs are expensive and reducing the number of wires used in a design to three wires would be beneficial. Scientific evaluations of the efficacy of three-wire electric fencing at deterring bears is lacking. In 2015 and 2016, I conducted a study in the Blackfoot Valley of Montana to evaluate the efficacy of rapid-deployment electric fencing designs in deterring bears from baited enclosures. Baited enclosures of two fencing configurations were established at 20 sites in the study area. Each enclosure was systematically energized and unenergized for 3-day periods; and passage into the enclosure was monitored with trail cameras to provide information on effectiveness and permeability. I recorded 134 visits by bears to fenced enclosures during the study seasons of 2015 and 2016. Of these visits, 78 occurred in 2015 and included 57 black bears and 21 grizzly bears. Fifty-six visits occurred in 2016, including 34 black bears and 22 grizzly bears. Black bears and grizzly bears were successful at passing the short fence 48% (95% CI: 32.0 -- 63.6) and 23% (5.0 -- 53.8) of the time, respectively, when it was not energized. When the short fence was energized, black bears were 7% (0.2 -- 33.9) successful in passing, whereas grizzly bears were successful in 25% (5.5 -- 57.2) of attempts. When not energized, both species successfully passed the tall fence design in 58% (95% CI: 27.7 -- 84.8) of attempts. Black bears and grizzly bears successfully entered energized enclosures with tall fences in 30% (95% CI: 13.2 -- 52.9) and 0% (95% CI: 0.0 -- 45.9) of attempts, respectively. Both fence types deterred bears from entering baited enclosures and all fences allowed less than perfect access when unenergized, suggesting that even minimalistic configurations of electric fences may act as barriers to black and grizzly bears. Further study evaluating the effects of rapidly increasing construction of electric fencing is needed to assess landscape level effects on bear movement and habitat selection.Item Varying nonlinear dependencies in habitat selection: estimating instead of imposing functional forms(Montana State University - Bozeman, College of Letters & Science, 2016) Ebinger, Michael Ryan; Chairperson, Graduate Committee: Robert A. GarrottSpatial heterogeneity of habitats and different foraging strategies can result in dissimilar patterns of habitat selection among individuals in a population. Studies have demonstrated that incorporating individual variation can influence model inferences. Thus, individual variation is increasingly being incorporated in habitat selection studies. Our objective was to advance the concept of individual variation in habitat selection by incorporating varying shapes (i.e., function forms) of responses among individuals. We used simulation modeling to develop a new analytical framework and introduce a new habitat selection metric, the Normalized Selection Ratio (NSR). Our results demonstrated the ability of the NSR to correctly estimate the strength and shape of complex simulated patterns of habitat selection, while simultaneously protecting against over-fitting. Using a simulated population of individuals, we showed how our approach can scale-up individual responses to facilitate population-level inference. We demonstrated how hierarchical clustering of individual-level response curves can identify and quantitatively describe different types of habitat selection within a population. When applied in a temporally dynamic framework, we showed that the NSR can detect ecological dynamics in habitat selection with quantitatively different inferences from analyses that pool data over time. We illustrated application of our approach using global positioning system (GPS) telemetry data for grizzly bears (Ursus arctos) in the Greater Yellowstone Ecosystem (GYE). We investigated the direction (preference or avoidance) and shapes of grizzly bear selection for whitebark pine (Pinus albicaulis) habitat during fall from 2007 to 2014. Our general conclusions support previous findings that grizzly bears exhibit a high degree of individual variation in habitat selection. Our approach of hierarchically clustering response curves detected 4 groups of grizzly bears with distinctly different patterns of whitebark pine habitat selection. Based on the group-level mean responses, 77% of sampled bears selected for whitebark habitat and 23% selected for non-whitebark pine habitats. Among the hierarchical groups that selected for whitebark pine, we observed substantial variation in the strength and density of whitebark pine being used. These results demonstrated the ability of our approach to identify, quantify, and organize individual differences in habitat selection and improve our understanding of grizzly bear ecology in the GYE.Item Carcass monitoring and grizzly bear scavenging across two management jurisdictions of the northern Yellowstone winter range (1997-2012)(Montana State University - Bozeman, College of Agriculture, 2016) Regan, Brooke Sierra; Chairperson, Graduate Committee: Bok SowellSpring ungulate carcasses are an important food source for grizzly bears (Ursus arctos) on the Northern Yellowstone Winter Range (NYWR). The objectives of this study were to: 1) provide a 1997 - 2012 update on spring carcass monitoring surveys across the NYWR, 2) compare grizzly bear use of carcasses in the spring between the Gallatin National Forest (GNF) and Yellowstone National Park (YNP), and 3) compare detection rates for two carcass survey techniques implemented on the GNF in 2006, 2008, and 2009. Carcasses occurred on the NYWR at low quantities (x= 31 carcasses per year), with the exception of 'pulse' events in 1997, 2006, 2008, and 2011 (x = 152 carcasses per year). On average, 76% of the carcasses on the NYWR were elk, and 57% were classified as adults. Wilcoxon rank sum tests indicated that both the proportion of carcasses used by grizzly bears and the number of carcasses used per kilometer of transect was less (P = 0.010 and P = 0.018, respectively) on the GNF than YNP in 'pulse years' and did not differ (P = 0.470 and P = 0.550) in years characterized by low carcass counts. Direct evidence of human activity was documented at 80% of all mature elk carcass sites on the GNF, and was estimated by YNP management to not exceed 1% of all carcass sites in YNP, although no data was collected. Density of roads was higher (P < 0.001) on the GNF than in YNP. I used a multiple logistic regression framework to assess the correlates of grizzly bear carcass use and found that the only significant parameter of ecological interest to predict grizzly bear use of carcasses was road density. The odds that grizzly bears scavenged on a given survey area in a given year decreased 83% for every 1 km/6.15 km 2 increase in road density. A Wilcoxon rank sum test of carcass detection rates for strategically and systematically placed transects revealed no differences or higher detection rate ranks for the less resource intensive strategic method. Managers of multi-use ungulate winter ranges may consider spring road closures that limit human activity, in order to enhance foraging opportunities for grizzly bears.Item The influence of mine reclamation and highway reconstruction activities on grizzly bear habitat selection in the Cooke City basin, Montana(Montana State University - Bozeman, College of Agriculture, 2016) Rossi, Joao Luiz; Chairperson, Graduate Committee: Bok SowellThe grizzly bear (Ursus arctos) population of the Greater Yellowstone Ecosystem is increasing in numbers and expanding its range. In this scenario, the number of conflicts between humans and grizzly bears is likely to increase. Understanding how grizzly bear habitat selection is affected by concentrated high human use, such as construction projects, plays a major role in management decisions for this species. In this research, we combined bear sign data collected in 27 permanent transects during 11 years (1990-91, 1996-97, 2003-04, and 2007-11) with food habits analysis to provide a description of grizzly bear habitat use in 91km 2 of the Cooke City Basin, Montana. Data were collected during years of mine reclamation (2003-04), highway reconstruction (2007-09), and years when no major human activities occurred (1990-91, 1996-97, and 2010-11). The main objectives of this study were to quantify grizzly bear spatial avoidance to mine reclamation and highway reconstruction activities and provide knowledge about environmental factors influencing grizzly bear habitat in the Basin. Resource selection functions were used to address these goals. Results showed that, in the Cooke City Basin, grizzly bears selected for mid-high elevation, forested, south-west facing slopes (areas where whitebark pine seeds are most abundant) and avoided areas of high tertiary road density. Mine reclamation occurred near whitebark pine forests. The estimated grizzly bear use of areas within 1 km and 2 km of reclamation epicenters decreased 83% and 52%, respectively, in years of mine reclamation. Grizzly bears did not avoid areas beyond 2 km of mine reclamation or areas within 4 km of highway reconstruction in years when these activities occurred. The lack of avoidance associated with highway reconstruction is likely explained by the fact that this occurred in the lowest elevation areas (below 2500 m) that are used less by grizzly bears. Grizzly bears use in the Cooke City Basin were mostly uninterrupted by two major construction projects. However, temporary and localized habitat loss occurred when construction was focused near whitebark forests with high bear use. Temporary habitat loss was not observed when construction occurred in areas distant from whitebark forests and used less by bears.Item Effects of livestock grazing on grizzly bear habitat along the east front of the Rocky Mountains, Montana(Montana State University - Bozeman, College of Letters & Science, 1988) Stivers, Thomas ScottItem Conservation genetics of grizzly bears(Montana State University - Bozeman, College of Letters & Science, 1994) Craighead, Frank Lance; Chairperson, Graduate Committee: E. R. Vyse; Peter F. Brussard (co-chair)
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