Theses and Dissertations at Montana State University (MSU)

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Carry-over effects in partially migratory greater sage-grouse, southwest Montana
(Montana State University - Bozeman, College of Letters & Science, 2022) Waxe, James Andrew; Chairperson, Graduate Committee: Andrea Litt; This is a manuscript style paper that includes co-authored chapters.
Migration is a common natural phenomenon and an important life history strategy for many animal species. Migration allows individuals to accommodate changing environmental conditions, with the potential to increase survival or future reproduction. Many migratory species are subject to carry-over effects, where conditions experienced during one season or life stage influence subsequent life stages. Previous research has largely focused on evaluating the influence of carry-over effects on long-distance migrants, but less is known about these influences on shorter-distance migrants. During research in southwest Montana and southeast Idaho, we used VHF radio collars, red blood cells, stable isotopes, and morphometric information to understand the influence of carry-over effects on Greater Sage-grouse. In this population, some individuals migrate only short distances, while others may not migrate at all. We evaluated the influence of 1) different migration strategies and breeding locations on the body condition of females before breeding and 2) how variation in pre-breeding body condition influenced subsequent reproduction. We found non-migratory individuals were in better pre- breeding body condition than migrants during years with less winter precipitation. Similarly, individuals who experienced less precipitation during the breeding season also had higher pre- breeding body condition. Pre-breeding body condition positively influenced offspring weight early in the breeding season, but this relationship was less apparent later in the season. Our data suggest carry-over effects occur in this population of sage-grouse, but the magnitude of these effects was largely dependent on environmental conditions and timing of breeding. With increasing evidence of carry-over effects in sage-grouse populations, managers should broaden their conservation strategies to account for all life stages. Protecting a variety of winter habitat both near and distant from breeding areas will ensure the persistence and reproductive contribution of individuals with different migration strategies. Furthermore, protecting all known sage-grouse leks provides variation within a single population which allows for flexibility to respond in changing environments. Maintaining or enhancing landscape-level habitat heterogeneity supports variable life-history strategies and is critical for sage-grouse conservation.
Variation of life-history strategies in pinnipeds with an emphasis on survival rates and spatial distribution of male Weddell seals in Erebus Bay, Antartica
(Montana State University - Bozeman, College of Letters & Science, 2020) Brusa, Jamie Louise; Chairperson, Graduate Committee: Jay J. Rotella; Jay J. Rotella, Robert A. Garrott, J. Terrill Paterson and William A. Link were co-authors of the article, 'Variation of annual apparent survival and detection rates with age, year, and individual identitiy in male Weddell seal (Leptonychotes weddellii) from long-term mark-recapture data' in the journal 'Population ecology' which is contained within this dissertation.; Jay J. Rotella, Katharine M. Banner and Patrick R. Hutchins were co-authors of the article, 'A comparative study evaluating how stage-specific survival rates vary with life-history traits in male pinnipeds' submitted to the journal 'Journal of evolutionary biology' which is contained within this dissertation.; Jay J. Rotella was a co-author of the article, 'Influence of age and individual identity in the use of breeding colony habitat by male Weddell seals (Leptonychotes weddellii) in Erebus Bay, Antarctica' submitted to the journal 'Journal of mammalogy' which is contained within this dissertation.
This dissertation explores various components of male life-history theory using a species-specific approach focusing on Weddell seals (chapters 2 and 4) and a comparative approach focusing on pinniped (seal and sea lion) species (chapter 3). To better understand how marine mammal populations can function and to gain insight about the evolution of male Weddell seal fitness, my coauthors and I estimated the age-specific survival rates of male Weddell seals living in Erebus Bay, Antarctica. Actuarial senescence (decreasing age-specific survival with increasing age) has been documented for several wildlife species. However, contrary to females, little information exists regarding age-specific patterns of survival, including actuarial senescence, for males. We used 35 years of mark-recapture data to estimate age-specific survival rates in male Weddell seals using a hierarchical model approach in a Bayesian framework. We found that male survival estimates were moderate for pups and yearlings, highest for 2-yearolds, and gradually declined with age thereafter such that the oldest animals observed had the lowest survival rates of any age, illustrating that male Weddell seals in this population exhibit actuarial senescence. We further investigated male Weddell seal ecology by describing the spatial patterns of male Weddell seals in Erebus Bay using regression modeling and kernel density methods. The intermediately aged males tended to have the most reproductive-age female neighbors, but individual heterogeneity played a stronger role than age. We found that younger males tended to settle in more offshore and less crowded areas of the habitat relative to older males. From a comparative approach, we assessed the patterns of tradeoffs among various fitness traits in male pinnipeds by examining the relationships between stage-specific survival rates and body size, baculum size, mating strategies, and delayed social maturity. Comparative studies similar to ours have tended to focus on females of avian and some terrestrial species and have mostly addressed reproductive traits. However, we lack information about males and connections between survival rates and other life-history traits. We found evidence for a relationship between precopulatory, rather than postcopulatory, traits and survival rates. We highlight the need for more empirical survival rate data and robust comparative methods.
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.
Characterizing summer roosts of male little brown myotis (Myotis lucifugus) in lodgepole pine-dominated forests
(Montana State University - Bozeman, College of Letters & Science, 2020) Hilty, Shannon Lauree; Chairperson, Graduate Committee: Andrea Litt
Although bat roosts have been well-studied in the eastern United States, we know less about roosts in the west. Western bats may make use of trees and snags, as in the eastern US, but the Rocky Mountains provide more exposed rock, which could contribute to western bat species using different roosting features. Additionally, roost studies often focus on maternity colonies, and information on roosts used by male bats is limited. Given that roosting sites may be limiting, we aimed to quantify structural features of roosts used by male little brown myotis (Myotis lucifugus) in forests dominated by lodgepole pine (Pinus contorta) during the summer and determine whether bats are selecting roosts with particular features disproportionately to what is available on the landscape. We mist-netted for bats during the summers of 2017 and 2018 and attached transmitters to 34 male little brown myotis. We located at least 1 roost for 20 individuals (average = 2.85 roosts/bat, range = 1-6). Although snags were available, most bats roosted in rock features (86% in rocks, 14% in snags); rock roosts were mainly in crevices with vertical orientations (85%) instead of rock cavities (15%). Male bats were more likely to select roosts with less canopy closure (mean for used locations = 14.1%, SE = 2.3) that were closer to water (1063.1 m, SE = 136.2). They also selected roosts with more overall rock cover (77%, SE = 3), wider entrances (3.1 cm, SE = 0.3), and access to a skyward-facing crevice, creating warmer microclimates. Our work indicates that rock features provide essential summer habitat for male little brown myotis and that lodgepole pine in this landscape may not provide appropriate roosting features. Understanding how other bat species may be using rock features, during summer and other seasons, remains a sizeable information gap. Learning more about hibernacula is of great importance due to the spread of white-nose syndrome and rock features may be essential autumn transitional roosts and winter hibernacula at higher elevations. Roosts that provide variation in microclimate, including the potential for passive warming, could be very beneficial for bats recovering from white-nose syndrome.
Spatial and temporal variability in movements and vital rates of sympatric salmonids in an unfragmented, inland watershed
(Montana State University - Bozeman, College of Letters & Science, 2019) Lance, Michael James; Chairperson, Graduate Committee: Alexander V. Zale
The life history patterns and vital rates of stream dwelling fish can differ across biological, spatial, and temporal scales. We determined the movement patterns and vital rates of three abundant salmonids--brown trout (Salmo trutta), mountain whitefish (Prosopium williamsoni), and rainbow trout (Oncorhynchus mykiss)--in the Smith River watershed of Montana, a system with three distinct geomorphic regions: the headwaters, semi-wilderness canyon, and prairie. We marked 7,172 fish with passive integrated transponder (PIT) tags, monitored their watershed-scale movements past 15 stationary PIT arrays over four years, and relocated fish between arrays by conducting mobile surveys along the Smith River and major tributaries. Fish movement patterns and survival probabilities varied seasonally, among species, and among locations within the watershed. Volume of movement and diversity of movers were both greatest in the canyon region and in lower portions of tributaries. Fish rarely left the canyon, but movement into the canyon from other regions was common among some groups of fish. Mountain whitefish were most likely to move and brown trout were least likely to move. The stream lengths traversed by fish followed a leptokurtic distribution with most fish travelling < 10 km and decreasing numbers of fish travelling farther. Distinct life history patterns were not evident as judged by the stream lengths traversed by tagged fish; rather, a continuous spectrum of distances traversed was apparent. Species-specific spawning periods were associated with increased frequency of movement by mountain whitefish and rainbow trout. Increases in the frequency of watershed-scale movements of all three species were associated mean daily water temperatures of 11.7-15.3°C, compared to periods when water temperatures were cooler or warmer. Annual probabilities of survival were highest among mountain whitefish (0.38-0.54) and lower among brown trout (0.16-0.38) and rainbow trout (0.08-0.39). Survival of rainbow trout and mountain whitefish was highest in the canyon. Survival of mountain whitefish was also high in the headwaters but was lowest in the prairie. Movements of fish in the Smith River watershed were diverse, allowed movement among habitats with different probabilities of survival, and probably contributed to meta-population function, population resiliency, and species diversity.
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.
Generalizing and transferring a GIS-based species distribution model: from one hot spot to another
(Montana State University - Bozeman, College of Agriculture, 2018) Garcia Neto, Narciso; Chairperson, Graduate Committee: Clayton B. Marlow
Species distribution models (SDMs) are efficient simulations of the distribution of species across geographical space and help to understand the spatial patterns of biological diversity. However, they are not designed to provide a description of species habitats. Geographic information systems (GIS) combined with SDMs have been used to illustrate the distribution and infer the sustainability and capability of habitats, to explore ecological relationships, serve as selection of vegetation types, avoidance of habitat disturbed by humans, establishing factors like predation, and to identify landscapes favorable for establishment of a new population. Despite the large number of SDMs papers published within the last decade, the practical utility of these models in the conservation management field remain sparse. The main objective of this research was to develop techniques for habitat modelling based on presence/availability data depicted by illustrative habitat maps and to test the new model on different landscapes. Resource selection function was used to develop a new model for the Yellowstone bison herd from published habitat maps. The predictor variables within the new model were elevation, ruggedness, profile curvature, percent of tree cove, Horizontal and vertical distance to water. The new model was then transferred and tested with field data from the National Bison Range and Grand Teton bison herds. The top predictive model performed better for the Yellowstone and Grand Teton herds than for National Bison Range herd. The output of this research indicated that habitat maps could work as source of land use by wildlife through transference to new areas of interest especially when local use data is not available.
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. Garrott
Spatial 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.
Space use and foraging patterns of the white-headed woodpecker in western Idaho
(Montana State University - Bozeman, College of Letters & Science, 2017) Kehoe, Adam Roarke; Chairperson, Graduate Committee: Jay J. Rotella
The white-headed woodpecker (Picoides albolarvatus) is a species of conservation concern that is strongly associated with ponderosa pine (Pinus ponderosa)-dominated forests in the Inland Northwest. More information on home range size and habitat selection patterns is needed to inform conservation of the white-headed woodpecker, a focal management species for dry-forest restoration treatments. We examined whether home range size was associated with food resources and if fine-scale habitat characteristics influenced selection of foraging sites. During the post-fledging periods of 2014 and 2015, we radio-tracked 11 white-headed woodpeckers in forests of west-central Idaho. These forests were historically managed for timber harvest, resulting in removal of large-diameter, cone-producing ponderosa pine trees. We hypothesized that ponderosa pine cones would be a highly-valued food resource providing seeds and arthropods. We expected smaller home ranges to be associated with a greater availability of cones for foraging and that cone foraging would be concentrated in core use areas. We used foraging behavior to test this hypothesis, specifically, the proportion of time foraging on cones as an index of cone availability. Home range sizes ranged from 24 to 169 ha (90% fixed-kernel estimates). Consistent with our hypothesis, individuals with relatively small home ranges spent a greater proportion of foraging time on cones (Beta superscript 1 [SE] = 2.48[1.32], P = 0.096; Beta superscript 2 [SE] = -5.00[1.61], P = 0.014). Cone foraging was also higher in core use areas compared to home range peripheries for individuals exhibiting at least moderate cone foraging. We also expected foraging woodpeckers to favor larger diameter pines in sites with moderate to high canopy closure. To test this hypothesis, we analyzed foraging-site selection by comparing habitat characteristics between foraging trees and available trees, which provided support for our foraging site prediction (Beta superscript TREEDIAMETER [SE] = 3.50[0.43], P <0.001; Beta superscript CANOPY [SE] = 1.74[0.41], P <0.001; Beta superscript SPECIES [SE] = 1.43[0.33], P <0.001). Our results suggest that large diameter pines provide important foraging resources, and that landscapes with more productive cone crops could support greater numbers of white-headed woodpeckers. We recommend restoration treatments that retain high-density patches of large diameter pines while promoting mosaics of open and closed canopies at larger spatial scales.
Characterizing habitat relationships and establishing monitoring strategies for an alpine obligate
(Montana State University - Bozeman, College of Letters & Science, 2016) Turnock, Benjamin Yasuo; Chairperson, Graduate Committee: Andrea Litt; Steven Kalinowski (co-chair); Andrea R. Litt, John M. Vore and Chris M. Hammond were co-authors of the article, 'Habitat characteristics of the hoary marmot : assessing distribution limitations in Montana' submitted to the journal 'Ecosphere' which is contained within this thesis.; Andrea R. Litt, John M. Vore and Chris M. Hammond were co-authors of the article, 'Monitoring hoary marmots at their southern extent : assessing design tradeoffs using occupancy' submitted to the journal 'Journal of wildlife management' which is contained within this thesis.
Alpine species have evolved to live in some of the harshest and most climatically diverse areas in the world, yet changes in climate are rapidly altering the areas alpine obligates call home. Warming temperatures are marching species to higher elevations and towards the poles, especially threatening species at the southern extent of their distributions. Understanding habitat requirements and monitoring abundance of species like the hoary marmot (Marmota caligata) at their southern extent will be crucial for tracking the magnitude of change that has begun in alpine ecosystems. We conducted double-observer occupancy surveys to collect presence-absence data and assess habitat characteristics important for the occurrence of hoary marmots; survey sites were within 5 mountain ranges in western Montana, the southern edge of this species' distribution. Marmots preferred shallow slopes, southern aspects, and areas with shrubs present. These preferences suggest that hoary marmots select habitat based on limitations they experience during both winter and summer, but winter conditions may play a stronger role in habitat selection. We then used our occupancy data to assess a broad suite of landscape variables at multiple spatial scales to create a predictive map of hoary marmot habitat throughout their distribution in Montana. We employed our predictive map to conduct a spatially-explicit power analysis and assess the ability of different monitoring strategies to detect a negative trend in abundance of marmot colonies. We were able to detect a 50% decline in colony abundance over 30 years by surveying 7-87% of sites > or = 4 times every 3 years. We found that we were more likely to detect a negative trend when the abundance of colonies was higher. Based on this information, we suggest that if management objectives include assessing population trend from occupancy, monitoring plans should be implemented sooner rather than later. Habitat associations and population status information are lacking for many species. Our study has provided a way to collect valuable information to monitor and manage an alpine species. The methods we have used can be applied to monitor other species that are hard to access and our results provide information for conserving alpine species over their distribution.

Theses and Dissertations at Montana State University (MSU)

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