Scholarship & Research
Permanent URI for this communityhttps://scholarworks.montana.edu/handle/1/1
Browse
3 results
Search Results
Item Wolverine habitat quality, connectivity, and prioritization at the landscape scale(Montana State University - Bozeman, College of Letters & Science, 2019) Carroll, Kathleen Anne; Chairperson, Graduate Committee: Andrew J. Hansen; Andrew J. Hansen, Robert M. Inman and Rick L. Lawrence were co-authors of the article, 'Comparing methods to disentangle habitat predictors for wolverines in the southern extent of their distribution' which is contained within this dissertation.; Andrew J. Hansen, Robert M. Inman, Rick L. Lawrence and Andrew B. Hoegh were co-authors of the article, 'Testing landscape resistance layers and modeling connectivity for wolverines in the western US' which is contained within this dissertation.; Robert M. Inman, Andrew J. Hansen, Kevin Barnett and Rick L. Lawrence were co-authors of the article, 'Prioritizing metapopulation connectivity for wolverines' which is contained within this dissertation.The core of conservation biology is understanding how to mitigate the impacts of anthropogenic activities on species. These impacts are particularly detrimental to isolated and small populations, which face extirpation or extinction without immediate conservation action. For small and isolated populations, protecting connective habitat (e.g., corridors) and facilitating movement is key. Corridor identification requires rigorous planning and appropriate statistical choices to ensure that resulting conservation actions are defensible and best support ecological processes. This manuscript asks: 1) how do different, commonly used statistical methods inform our understanding of species resource selection across scale and between sexes, 2) how does landscape resistance and connectivity differ between resident and dispersing individuals, and 3) what information is important to include in a systematic conservation plan to best support on-the-ground conservation between land trusts, landowners, and other practitioners under future climate change conditions. To address each of these questions we focused on wolverines (Gulo gulo), which exist as isolated metapopulations across the western contiguous United States. Our key findings included that 1) the importance of habitat variables differ only slightly by sex, across selection scales, and across analysis methods, 2) dispersing animals are less sensitive to habitat quality compared to resident animals, and 3) including information that both helps mitigate potential threats and preserves ecological processes is the best approach for connectivity conservation planning. This work represents the most comprehensive wolverine connectivity conservation analyses to date. This research suggests that examining multiple approaches and validating results is critical to generating rigorous and defensible conservation decisions are being made for wolverines, although more studies are needed to validate this in other species. Taken together, this research provides land managers, policy makers, and scientists with guidance for future connectivity analyses, conservation action for wolverines, and a research framework that can be applied to additional species of conservation concern in isolated populations.Item Connectivity in a montane river basin : salmonid use of a major tributary in the Smith River system(Montana State University - Bozeman, College of Letters & Science, 2015) Ritter, Thomas David; Chairperson, Graduate Committee: Alexander ZaleThe Smith River is a popular recreational sportfishery in western Montana, but salmonid abundances there are relatively low and limited by high summer water temperatures and low discharges. Smith River tributaries may serve as thermal refuges and also as important spawning and nursery areas. Tributaries unaltered by anthropogenic disturbances may be especially important. If so, maintaining connectivity between the main-stem river and its tributaries would be essential. Moreover, an understanding of salmonid habitat use and management in a stressed system could help identify potential climate change adaptation strategies and tactics. My goal was to determine the roles of a major undisturbed tributary in the life histories and movements of salmonids in a montane river basin. My focus was on Tenderfoot Creek, a remote, unaltered major tributary to the Smith River. A PIT-tag detection network monitored the seasonal movements of rainbow x cutthroat hybrid trout, Mountain Whitefish, Brown Trout, and Brook Trout. Abundances were estimated by electrofishing and snorkeling. Despite thermally stressful conditions in the Smith River, no tagged fish were directly observed using Tenderfoot Creek as a thermal refuge, although such use probably occurred at the confluence within the Smith River. Interchange between Tenderfoot Creek and the Smith River was common for Brown Trout, Mountain Whitefish, and rainbow x cutthroat hybrid trout and consisted mostly of spawning migrations. Some large, presumably dominant Brown Trout appeared to establish permanent territories within Tenderfoot Creek. Spawning effort by Mountain Whitefish and rainbow x cutthroat hybrid trout was high; about 7,568 Mountain Whitefish were observed in spawning aggregations in autumn and estimated abundance of rainbow x cutthroat hybrid trout juveniles (N = 25,127) was much higher than that of other taxa. Brown Trout also spawned in Tenderfoot Creek (159 redds counted in 2011 and 2012), and Brook Trout spawned in side channels and tributaries. Tenderfoot Creek is heavily used by Smith River fishes for spawning; maintaining its connectivity and habitat quality is therefore beneficial to recruitment to the Smith River fishery.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.