Theses and Dissertations at Montana State University (MSU)
Permanent URI for this collectionhttps://scholarworks.montana.edu/handle/1/733
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Item Multi-scale assessment of semi-arid vegetation communities: climate, disturbance, and environment as spatiotemporal drivers of phenology and composition(Montana State University - Bozeman, College of Agriculture, 2021) Wood, David Jonathan Adrian; Chairperson, Graduate Committee: Scott Powell and Paul C. Stoy (co-chair); This is a manuscript style paper that includes co-authored chapters.Ecosystems processes and functions include hierarchical and complex drivers. Assessing drivers of variation at multiple scales therefore helps predict biotic responses and improves our overall understanding of ecosystems. For example, the seasonal cycle and duration of events, phenology, represents a foundational process sensitive to changes in climate, and has cascading impacts across the ecosystem. The long-term record and expansion of remote sensing techniques provides an opportunity to both assess phenological changes through time at broad spatial extents while also assessing variability at finer spatial scales. At regional extents, satellite-based measurement can provide key insights into community level shifts, while finer scaled techniques such as unpiloted aerial vehicles (UAVs), spectral sensors, and automated digital cameras (phenocams) can investigate pattern differences at centimeter scales (i.e., plant and functional groups). I analyzed the year to year and spatial variability of phenology and composition of rangeland systems over multiple spatial scales to explore interrelated aspects of ecosystem functions. I used the AVHRR satellite record of phenology to examine spatial and temporal variability in phenological drivers and to identify key drivers and differences between the phenology of communities, including the role of ecological memory, the legacy impact of prior climate over months to years. In addition, by employing UAVs, spectral sensors, and phenocams I investigated the pattern and influence of heterogeneity on the phenology of grasses and shrubs. Finally, I investigated the interaction of multiple disturbances on the relative proportions of vegetation functional groups within a community. Key findings include productivity tradeoffs, where higher annual temperature increased peak but decreased growing season long productivity; climate conditions from the prior season and up to four prior years influenced date and productivity phenological measures; near earth sensors can characterize phenological variation at the microsite level; and there is an interactive effect of fire and development disturbance on non-native annual grass expansion. The vegetation of U.S. rangelands is projected to have consequential impacts from climate change, especially summer drying, and these impacts can be better quantified by including antecedent conditions and incorporating microsite differences into predictive models.Item Reproductive biology and phenology of western pearlshell mussels in Montana(Montana State University - Bozeman, College of Letters & Science, 2022) Cook, Kristen Ann; Chairperson, Graduate Committee: Alexander V. ZaleThe Western Pearlshell mussel is the only native freshwater mussel inhabiting trout streams of western Montana; it has been designated a state Species of Concern because of declines in abundance and distribution. Conservation of Western Pearlshells in Montana will require fundamental information on their reproduction and life-history traits that is currently lacking. We therefore estimated the age and length at sexual maturity and incidence of hermaphroditism in mussels using histology. We determined the timing of reproductive events (spawning, brooding, embryogenesis, larval release, and larval infestation of hosts) and their relationship to temperature by collecting gonadal and marsupial biopsies to identify gamete presence and embryo developmental stages, visually identifying brooding mussels, and examining captured fish for the presence of mussel larvae. We identified the hosts of Western Pearlshells in nature by quantifying the probability of infestation and infestation intensities among salmonid species. Mussels reached sexual maturity at an estimated 34 mm in length and 11.5 years of age. Of 31 mature mussels examined histologically, all but one were gonadal hermaphrodites. The reproductive phenology of Montana Western Pearlshells differed among populations and years. Mussel populations brooded for about 24 to 39 days in May and June. Embryogenesis was synchronous among individuals in all populations except one and was about two to three weeks in duration. The larval infestation period generally occurred in June and July and was 47 to 71 days in duration. Some larvae grew > 400% in length before leaving the host. Gonadal recrudescence was rapid whereby mussels possessed mature or nearly mature gametes by early autumn. Both photoperiod and temperature appear to influence the timing of reproductive events. Native Westslope Cutthroat Trout and nonnative Brook Trout were the most susceptible fish species to infestation of Western Pearlshell larvae. Nonnative Brown Trout were moderately susceptible to infestation in the Flint-Rock watershed. Nonnative Rainbow Trout and native Mountain Whitefish were least likely to be infested with mussel larvae. Our findings will inform future conservation and propagation efforts of Western Pearlshells in Montana.Item Distribution, phenology, growth, and overwinter mortality of age-0 smallmouth bass in the Yellowstone River, with implications for upstream range expansion(Montana State University - Bozeman, College of Letters & Science, 2020) Voss, Nicholas Sheridan; Chairperson, Graduate Committee: Alexander V. Zale; Robert Al-Chokhachy, Adam J. Sepulveda, Christine E. Verhille, Michael P. Ruggles and Alexander V. Zale were co-authors of the article, 'Distribution, phenology, growth, and overwinter mortality of age-0 smallmouth bass in the Yellowstone River, with implications for upstream range expansion' submitted to the journal 'Transactions of the American Fisheries Society' which is contained within this thesis.Non-native fish introductions are a leading threat to freshwater biodiversity, and accurate assessments of future impact are often hindered by the challenge of anticipating future range expansion. Successful introductions of non-native Smallmouth Bass Micropterus dolomieu have occurred globally and often exhibit secondary spread to upstream habitat. This has occurred in the Yellowstone River, Montana (USA). Observations of adults in socio-economically valuable trout habitat have highlighted a need to better understand the controls on the upstream distribution of Smallmouth Bass in this system, particularly the influence of cold upstream climates on first-year growth and size-selective overwinter mortality (a potential life history bottleneck at northern latitudes). We documented the phenology, growth, and survival of age-0 Smallmouth Bass in relation to water temperature between the uppermost distribution of adults, and downstream regions where they are abundant. Successful reproduction (i.e., age-0 presence) was rare or absent throughout the uppermost 150 km of the upstream distribution of adults, suggesting that something currently prevents or discourages successful reproduction farther upstream. Surprisingly, the mean late-autumn body size of age-0 Smallmouth Bass did not differ significantly among the uppermost 200 km of their distribution, despite upstream declines in ambient water temperature. Although water temperature was a key attribute affecting age-0 growth, upstream shifts towards earlier hatching mediated the expected negative effect of colder upstream climates. Furthermore, surveys of overwinter survivors and simulations of age-0 starvation mortality indicated that age-0 individuals at the upstream extent of their distribution successfully recruited to the age-1 year-class in four consecutive years. Taken together, our results suggest that Smallmouth Bass have not yet reached the thermal limit of their upstream distribution, and that first-year growth, survival, and consequent spread by this non-native predator are probably driven by the complex interactions of spawn timing and ambient thermal and hydrologic regimes in the Yellowstone River.Item Effects of seasonal precipitation and habitat associations on the demographics of Mexican spotted owl prey in the canyonlands region of southern Utah(Montana State University - Bozeman, College of Letters & Science, 2018) Thornburg, John Ramsey, III; Chairperson, Graduate Committee: David WilleyMost food habit studies of Mexican Spotted Owls (Strix occidentalis lucida) have been conducted in forested environments in more southern portions of their range. Through regurgitated pellet analyses, these studies showed the majority of Mexican Spotted Owl prey consumed was comprised of Cricetid rodents, specifically woodrats (Neotoma spp.) and white-footed mice (Peromyscus spp.). In the northernmost portions of their range, Mexican Spotted Owls inhabit rocky canyon habitats within the Colorado Plateau. In the canyonlands region, few studies have investigated the population ecology and habitat associations of the primary prey of spotted owls and no studies have examined the relationships among primary prey demographics and their responses to seasonal precipitation. Given the Mexican Spotted Owls status as a threatened species, increased knowledge of prey species relationships with climate and habitat may assist in future management of spotted owl populations across the canyonlands region. Using a seven-year historic data set collected at three study sites in Grand Staircase -- Escalante National Monument from 2001 to 2007 and three years of data collected at five study sites in Capitol Reef National Park from 2013 to 2015, I described the nocturnal small mammal communities, investigated primary prey habitat and microhabitat component associations, and investigated the effects of timing and amount of seasonal precipitation on primary prey abundance and diversity in both study areas. Cricetid rodents were the most abundant nocturnal small mammals and potential prey available for spotted owls inhabiting rocky canyon habitats. Microhabitat analyses revealed Cricetid rodents partitioned space and resources that minimized interspecific competition enabling coexistence in narrow canyon systems with limited biological resources. Linear mixed-effects modeling indicated winter precipitation was the primary driver of spotted owl primary prey demographics in the canyonlands region.Item Environmental drivers of salmonfly ecology in southwest Montana(Montana State University - Bozeman, College of Letters & Science, 2018) Anderson, Heidi Elise; Chairperson, Graduate Committee: Lindsey Albertson; Lindsey K. Albertson and David M. Walters were co-authors of the article, 'Temperature-driven range contraction and body size reduction of an iconic aquatic insect' submitted to the journal 'Freshwater science' which is contained within this thesis.; Lindsey K. Albertson and David M. Walters were co-authors of the article, 'Landscape features drive synchronicity of an aquatic insect resource pulse' submitted to the journal 'Ecological applications' which is contained within this thesis.Aquatic insects have ecological, cultural, and economic value throughout the American West. They can control the processing of in-stream nutrients, are a vital component of both aquatic and terrestrial food webs, and support economically important species such as trout and the eco-tourism industries structured around these fisheries. Salmonflies (Pteronarcys californica) are one of the most well-known aquatic insects in the American West due to their large size and popularity among fly-fishers. However, mounting anecdotal evidence suggests that salmonfly populations could be in decline. We conducted surveys and compiled historical datasets that quantified salmonfly abundance, body size, and emergence timing along the Gallatin and Madison Rivers in southwest Montana to determine the status of salmonfly populations in these rivers, understand environmental drivers that are constraining their distribution and driving their development, and initiate long-term monitoring. Most notably, we found evidence for temperature-driven changes in salmonfly distribution and body size along the Madison River in the last four decades and observed marked differences in salmonfly emergence phenology and duration at multiple spatial scales between the Madison and Gallatin Rivers. Above-optimal summer water temperatures appear to be the major constraint on salmonfly populations in the Madison River, but only play a minimal role in dictating salmonfly distribution along the Gallatin River. This research provides rare empirical evidence of long-term biological change of an aquatic insect and highlights the importance of combining temporal and spatial datasets to explicitly address species' responses to environmental stressors across multiple spatial and temporal scales. Freshwater habitats are increasingly imperiled by climate change and human-induced habitat alteration, which will invariably continue to impact the ecology of aquatic insects like salmonflies. This work contributes to the understanding of how these ongoing changes will influence the structure of aquatic communities, the flow and transfer of energy and nutrients, consumer-resource dynamics, and stream--riparian food web linkages.Item Evaluation of calving seasons and marketing strategies in Northern Great Plains cow-calf enterprises(Montana State University - Bozeman, College of Agriculture, 2001) Reisenauer, Vicki LynnItem Plant phenology in the western United States using the ERTS-1 satellite(Montana State University - Bozeman, College of Agriculture, 1976) Jones, Charles MoncurItem Early vegetative and heading phenology of barley accessions grown in moderate and long daylengths in controlled environment chambers and field environments(Montana State University - Bozeman, College of Agriculture, 1980) Brown, Gregory AllenItem 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.Item Remote sensing grassland phenology in the greater Yellowstone ecosystem : biophysical correlates, land use effects and patch dynamics(Montana State University - Bozeman, College of Letters & Science, 2012) Piekielek, Nathan Brian; Chairperson, Graduate Committee: Andrew J. HansenVegetation phenology refers to the seasonal timing of repeat biological events such as bud burst and primary-productivity and their relationship to climate. The spatial location and timing of phenology is relevant to a wide-variety of questions in ecology including the space use and population dynamics of migratory herbivores. Recent technological (remote sensing) and methodological (statistical smoothing algorithms and weighted-regression) advancement now allow for mapping spatial and temporal patterns of vegetation phenology across large spatial extents and at fine-temporal scales. It also allows for examination of vegetation response to climate. An understudied topic investigates how human activity (i.e. land use) modifies broad-scale patterns of phenology from their natural state. Land use effects on phenology is important in the context of parks and protected areas where human activity in surrounding areas can compromise biodiversity conservation goals. With this in mind, we posed the following research questions for a study-area within the Greater Yellowstone Ecosystem: 1) What are the biophysical correlates and likely drivers of landscape-scale grassland phenology under wildland conditions? 2) How do different types of land use modify grassland phenology from its wildland state? And, 3) Do spatial and temporal patterns of green forage patches produced with new tools and datasets display seasonal-dynamics that are consistent with current ecological understanding? To answer these questions we used the Normalized Difference Vegetation Index (NDVI) produced by the Moderate Resolution Imaging Spectroradiometer (MODIS) as input to the TIMESAT algorithm to produce estimates of grassland phenology. Our principle findings are that: 1) Seasonal variation in solar radiation, water availability, evaporative demand and temperature explained much of the variation in the timing of wildland grassland phenology; 2) All land use types extended the length of the growing season and agriculture increased two estimates of productivity; And, 3) New tools are capable of producing nearly-spatially and -temporally continuous maps of the pattern of green forage patches that are consistent with current ecological understanding. Results of the present study suggest that land use intensification in the Greater Yellowstone Ecosystem has the potential to alter landscape-scale ecosystem process with a variety of expected consequences for wildlife conservation and management.