Theses and Dissertations at Montana State University (MSU)
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Item Investigations into the West Indian Chelonarium (Coleoptera: Chelonariidae) and the Antherophagus (Coleoptera: Cyptophagidae) of Montana(Montana State University - Bozeman, College of Agriculture, 2022) Kole, John Paul; Chairperson, Graduate Committee: Michael A. Ivie; This is a manuscript style paper that includes co-authored chapters.The discovery of a new species of Chelonarium in southern Florida, combined with the expected publication of the next edition of American Beetles requires has made it necessary to revise the West Indian Chelonariidae. Material from the West Indies was examined, names were associated with species, and species level groups were determined. Sixteen species are recognized with species definitions, descriptions, distributions, and illustrations provided. A key to the species is included. Seven species are redescribed: Chelonarium beauvoisi Latreille, 1807, Chelonarium convexum Mequignon, Chelonarium problematicum Mequignon, Chelonarium cupreum Mequignon, Chelonarium lecontei Thomson, Chelonarium maculatum Mequignon, and Chelonarium pilosellum Chevrolat. A neotype is designated for Chelonarium convexum Mequignon. Chelonarium costattipenne Mequignon, new synonymy, and Chelonarium sublavae Mequignon, new synonymy, are placed as junior synonyms of Chelonarium problematicum Mequignon. Eight species are described as new: Chelonarium auricomus Kole and Ivie, new species, Chelonarium calcarium Kole and Ivie, new species, Chelonarium floccum Kole and Ivie, new species, Chelonarium grenadensis Kole and Ivie, new species, Chelonarium latosetum Kole and Ivie, new species, Chelonarium lucidum Kole and Ivie, new species, Chelonarium nitidellum Kole and Ivie, new species, and Chelonarium sabensis Kole and Ivie, new species. Chelonarium auricomus is the second US mainland species and is apparently introduced from the Martinique and/or St. Lucia. Chelonarium punctatum Fabricius, 1801 and Chelonarium atrum Fabricius, 1801 are removed from the West Indian Fauna because of newly clarified type localities, corrected to Essequibo, British Guyana. A discussion of biogeography is provided. The Chelonariidae of the West Indies are far more diverse than was previously known, however more data is required to better determine the diversity of this group in the West Indies. Little is known of the beetles which live in the nests of wild bees. One such genus, Antherophagus, which lives in the nests of Bombus, was almost entirely unknown from Montana. Material from the MTEC was examined and species were identified using preexisting keys. A key is provided for all five North American Antherophagus, new county and state records are reported, and biology is discussed. The Antherophagus are likely more widely distributed than is currently reported.Item Reconstructing large herbivore abundance and environmental interactions in postglacial North America(Montana State University - Bozeman, College of Letters & Science, 2023) Wendt IV, John Arthur Frederic; Chairperson, Graduate Committee: David B. McWethy; This is a manuscript style paper that includes co-authored chapters.Large herbivores drive critical ecological processes, yet their long-term dynamics and effects are poorly understood due to the limitations of existing paleoherbivore proxies. To address these shortcomings, long-term records of paleoherbivores were constructed by (i) applying new analytical techniques to existing bison fossil datasets; and (ii) examining fecal steroid data that characterize temporal changes in ungulate abundance and community composition. These paleoherbivore reconstructions were analyzed in relation to their environmental contexts to better understand herbivore-ecosystem interactions through time in three separate studies: First, spatiotemporal changes in postglacial bison distribution and abundance in North America were examined by summarizing fossil bison observations. Bison observations were compared with simulated climate variables in a distribution modeling framework to project probable bison distributions in 1000-year intervals from the Last Glacial Maximum to present in light of changing climatic drivers over time. Since the Bolling-Allerod Interstadial (14.7-12.9 ka) the geographic distribution of bison is primarily explained by seasonal temperature patterns. Second, Holocene records of bison abundance were compared to paleofire reconstructions spanning the midcontinental moisture gradient to determine the relative dominance of herbivores and fire as biomass consumers. Bison dominated biomass consumption in dry settings whereas fire dominated consumption in wetter environments. Historical distributions of herbivory and burning resemble those of Sub-Saharan Africa, suggesting a degree of generality in the feedbacks and interactions that regulate long-term consumer dynamics. Third, the utility of fecal steroids in lake sediments for reconstructing past herbivore abundance and identity was tested by (i) characterizing the fecal steroid signatures of key North American ungulates, (ii) comparing these signatures with multiproxy data preserved in lake sediments from the Yellowstone Northern Range, and (iii) comparing influxes of fecal steroids over time to historical records of ungulate biomass and use. Bison and/or elk were abundant at Buffalo Ford Lake over the past c. 2300 years. Ungulate densities in the watershed were highest in the early 20 th century and likely contributed to decreases in forage taxa and possibly increased lake production. These results demonstrate long-term ecological impacts of herbivores and highlight opportunities for continued development of paleoherbivore proxies.Item Evolutionary consequences of gene flow in the absence or inhibition of dispersal in microbial communities(Montana State University - Bozeman, College of Agriculture, 2023) Munro-Ehrlich, Robert Mason; Chairperson, Graduate Committee: Jovanka Voyich-Kane; This is a manuscript style paper that includes co-authored chapters.Much of our understanding of the evolutionary dynamics of microbial populations is derived from population level studies which focus on the immediately present populations and ignore the contributions of nearby communities. Microbial ecology studies typically do not distinguish between gene flow, i.e., the movement of genetic material between populations, and dispersal, i.e., the movement of those populations themselves. These two processes are indeed linked, but not identical. We have known for centuries that genetic material can be transferred between physically distant and taxonomically disparate microbial populations; molecular biology tools like cloning are dependent on this capability. In other words, gene flow can occur even without dispersal. However, our ecological and evolutionary studies of microbial populations typically fail to acknowledge the evolutionary impact and genetic contributions of outside populations. Unique evolutionary scenarios arise when dispersal between two or more populations is prevented or limited, but gene flow can still occur between them. We hypothesized that this scenario would impact microbial populations by facilitating speciation, selection, and local adaptation. We aimed to test this hypothesis by studying endemic Meiothermus populations inhabiting serpentinite rocks in the subsurface of the Samail ophiolite in Oman. Samail Ophiolite microbial communities, of which Meiothermus populations are a component, are dispersed across the subsurface and separated by meters of solid rock and by chemical and pH gradients spanning orders of magnitude. Despite barriers to dispersal that are significant enough to shape community structure, we found that gene flow still occurred between nearly all observed populations of Meiothermus. This gene flow is contributing to disruptive selection amongst cohabiting populations, and may also be contributing to local adaptation, both at the genetic and genomic level. We also identified potential mechanisms for this gene flow, including abundant viral elements. The sequence similarity of mobile genetic elements in these Meiothermus populations implies that this gene flow occurred after colonization by a common Meiothermus ancestor and that diversification is likely ongoing. To our knowledge, this is the first demonstration of gene flow across barriers to dispersal in an environmental microbial system. In conclusion, these results suggest that the capacity for microbial populations to undergo gene flow even in the absence or inhibition of dispersal is a natural process, has substantial consequences for the evolution of the effected population, and may also have consequences for the microbial and surrounding environment.Item Effects of de-snaring on the demography and population dynamics of African lions(Montana State University - Bozeman, College of Letters & Science, 2023) Banda, Kambwiri; Chairperson, Graduate Committee: Scott CreelLions and other African large carnivores are in decline, due in part to effects of illegal hunting with snares, which can reduce prey availability and directly kill or injure carnivores. It is difficult to effectively remove snares from large ecosystems by patrolling, but an additional approach to reduce effects on large carnivores is to monitor the population closely and de-snare individuals who are found in a snare or have broken free but still carry the wire (often with serious injury). The effectiveness of de-snaring programs to reduce impacts on large carnivores has not been directly tested. Here, we used long-term demographic data from 386 individually identified lions in the Luangwa Valley Ecosystem to test the effects on population growth (lambda) and population size (N) of a program to remove snares from injured lions and treat their wounds. Stochastic Leslie matrix projections for a period of five years showed that the population grew with the benefits of de-snaring but was expected to decline without de-snaring. Mean annual growth (lambda) was 1.037 (growth in 70% of years), closely matching observed changes in population size. Mean annual growth was 0.99 (with growth in 47% of years) for a model that assumed snared animals would have died if not treated, and 0.95 (with growth in 37% of years) for models that also accounted for super-additive effects via the death of dependent cubs and increased infanticide with increased male mortality. De-snaring requires intensive effort, but it can appreciably reduce the effect of snaring on lion population dynamics.Item Movement ecology of female sage-grouse informs space use, resource selection, and demography in southern Valley County, MT(Montana State University - Bozeman, College of Agriculture, 2023) Haynam, Robert Thomas, III; Chairperson, Graduate Committee: Lance McNew; This is a manuscript style paper that includes co-authored chapters.The greater sage-grouse (Centrocercus urophasianus) is a focal species in the effort to conserve imperiled sagebrush ecosystems and associated organisms. Sage-grouse uses of landscapes are modulated by their multilevel movement processes. Understanding the relative contributions of hard-wired and environmental influences on movement processes is necessary for a comprehensive understanding of sage-grouse ecology. Correlates between fitness components and measurable landscape conditions may be of limited value if other influences such as sage-grouse movement and behavior are not accounted for. Movement behaviors may be risky in certain contexts and adaptive in other contexts, and differences in the characteristics of movement and therefore space-use among individuals can have implications for survival and reproductive performance. We collected detailed records of sage-grouse movements for up to 4 years per individual to investigate daily behavioral strategies of sage-grouse and therefore mechanisms driving habitat use and individual performance. During April-May, 2018-2019, we captured 86 (45 in 2018, 41 in 2019) female sage-grouse and outfitted them with GPS transmitters. We collected 192,640 geographic coordinates of 86 female sage-grouse during 2018-04-24 - 2022-04-14 which encompassed 4 complete annual cycles of sage-grouse. We confirmed 185 nest attempts of 76 individuals during the nesting seasons of 2018-2021. Hard-wired or learned seasonal behavior modes appeared to be more influential than vegetation conditions. Sage-grouse can exhibit reactive responses to landscape conditions but also use the landscape as a function of high-level endogenous constraints likely due to memory mechanisms, high temporal predictability of some resources, and moderate spatial heterogeneity of resources. Management prescriptions may ignore important ecological levels such as those responsible for learned-heuristic movement and space use modes. Relationship and magnitude of associations among sage-grouse use-intensity and landscape conditions varied among 7 behavior modes which indicates that behavioral and temporal context is important for understanding habitat and space use by sage-grouse. Our findings also support a fundamental demographic importance of area affinity, fidelity, and familiarity to sage-grouse ecology which has been overlooked in most research on sage-grouse or other birds.Item The Megachile (Hymenoptera: Megachilidae) of Montana and checklist of bees (Hymenoptera: Apoidea) from the southern Wolf Mountains, Montana and Wyoming(Montana State University - Bozeman, College of Agriculture, 2021) Pritchard, Zoe Anne; Chairperson, Graduate Committee: Michael A. IvieWild bees are a diverse group of important pollinators, yet several aspects of their biology remain understudied. In particular, baseline data on the diversity and geographic ranges of wild bees is not available for much of Montana. These baseline faunistic data are the first step to understanding the regional biodiversity of bees and to eventually assess their conservation status. We conducted faunal surveys of the genus Megachile in Montana and the bees of the southern Wolf Mountains. Specimens from collecting trips in 2019-2020, historic museum specimens, research collections, and published data records comprise the foundation for the inventory of Montana's Megachile species. We documented 35 species of Megachile in Montana based on 4,968 specimens and present an illustrated identification key and county distribution maps. In the Wolf Mountains, we documented 138 bee species from 4,996 specimens collected on trips in 2019-2020 in Montana and Wyoming. These two studies contribute eight new state records and add important data to the growing list of bee species in Montana.Item Aphanomyces euteiches spatial distribution, host studies, and characterization in Montana(Montana State University - Bozeman, College of Agriculture, 2022) Murphy, Carmen Yvette; Chairperson, Graduate Committee: Mary BurrowsGrowing pulse crops in Montana has been inhibited by biotic constraints to production, including a complex of pathogens causing root rot. Aphanomyces root rot, caused by the soilborne oomycete, Aphanomyces euteiches, causes plant stunting and yellowing, root browning and constriction, and reduces yield in dry pea and lentil in the state. Twelve fields with a history of pulse root rot were sampled in northeast Montana with three 100 m entrance transects and one 50 m transect at a low spot or problem area. Soil from each 10 m quadrat within transects was assessed for root rot using a greenhouse bioassay with a susceptible dry pea variety, and with PCR. Samples were also analyzed for soil properties and nutrients. Distribution of the pathogen was sporadic in most fields, except for fields that had been growing pulses in a consistent rotation, where root rot severity was high and consistent. Soil pH, organic matter, potassium, and sulfur concentration were correlated with Aphanomyces root rot, and isolates varied in their response to acidic pH in vitro. Using a highly virulent A. euteiches isolate, greenhouse trials were conducted to assess the pathogen load of inoculated soil after growing host and non-host plant species, measured with a bioassay. Greenhouse pots were inoculated with 500 oospores per gram prior to planting plant treatments. Growing host plants resulted in higher root rot severity on dry pea bait plants compared to non-host plant treatments. When five cycles of plants were grown in greenhouse pots inoculated with A. euteiches, using five 'rotation' treatments, one treatment with three consecutive rounds of non-host plants reduced the disease severity score in one trial repetition compared to treatments with less than three successive rounds growing a non-host. This research indicates that sampling strategies for Aphanomyces root rot requires multiple sampling locations within a field to enhance the probability of detection, and that crop rotation is an important tool for management of pathogen load in the soil.Item Woody plant expansion in the northern Great Plains: a multi-scale assessment of the drivers and ecological implications of increasing woody abundance in a temperate open ecosystem(Montana State University - Bozeman, College of Agriculture, 2022) Currey, Bryce Alan; Chairperson, Graduate Committee: Jack Brookshire; This is a manuscript style paper that includes co-authored chapters.Open ecosystems (i.e., non-forested ecosystems) are inherently dynamic ecosystems that are essential to the persistence of humankind; yet many are being altered, degraded, or lost. One of the largest changes to open ecosystems globally is an increase in greenness, driven by increasing plant photosynthetic capacity or altered species composition. Often this transition in species composition occurs when woody species (i.e., trees and shrubs) increase in dominance or replace contemporary herbaceous species, a phenomenon referred to here as woody plant expansion (WPE). WPE has been proposed as a possible solution to climate change, yet ultimately has the potential to alter grasslands into a novel state. This dissertation improves the understanding of how open ecosystems have been altered by WPE. The chapters within this document offer a multi-scalar examination of the drivers and ecological implications of WPE in the Northern Great Plains (NGP) of North America, one of the largest grasslands remaining globally. Specifically, I answer three main questions: (1) What is the extent and magnitude of WPE across the NGP? (2) What are the drivers, ecosystem implications, and biogeochemical impacts of WPE? and (3) Moving forward, how should research be prioritized in ecosystems like the NGP, particularly concerning climate mitigation and management? I begin with an introduction to the NGP, the implications of WPE, and an overview of this dissertation. I then examine the drivers and interactions of WPE and the recent increase in vegetative productivity. Next, I couple high-resolution estimates of WPE from the heart of the NGP with data from sampling plots to examine the impact that WPE has on ecosystem biogeochemistry. Next, WPE is examined against agricultural expansion and I propose that future work examining large-scale changes and the subsequent management of open ecosystems be reframed towards weighing the impacts on biodiversity, carbon storage, and ecosystem resilience. Finally, I summarize all findings with implications for future research. The NGP has the potential to represent the future of North American grasslands and, while this dissertation answers many questions, the future remains highly uncertain.Item Effect of landscape fragmentation on bat population dynamics and disease persistence in Uruguay(Montana State University - Bozeman, College of Agriculture, 2021) Botto Nunez, German; Chairperson, Graduate Committee: Raina K. Plowright; This is a manuscript style paper that includes co-authored chapters.The transmission of pathogens into novel host species, a process known as spillover, requires a series of conditions to align in space and time. A series of imperfect barriers prevent the jump of pathogens from one species to others. These may include the distribution and abundance of the primary host, the survival of the pathogen in the environment and the susceptibility of the recipient host to the pathogen. Only when permissive conditions align in time and space can the spillover occur. Spillovers may be relatively rare events and the understanding of the dynamics of the barriers is constrained by the ability of detecting and analyzing such events. Systems where spillover does not occur, despite apparent presence of all required conditions, provide an opportunity to understand barriers preventing inter-species transmission. Vampire bat-borne rabies in Uruguay provides such an opportunity. Despite large and stable livestock density, presence of vampire bats, and circulation of the virus in close proximity, the country did not experience livestock rabies outbreaks until 2007. Here we combined historical review, field sampling, and statistical and mathematical modeling to understand the factors driving the emergence of rabies in Uruguay in 2007 and the previous absence of the disease. Our results suggest that rabies outbreaks in the country are spatially and temporally associated with fragmentation of grasslands. We showed that proposed increased connectivity among colonies, in response to fragmentation, is sufficient to explain longer persistence of the virus in the bat colonies, allowing more opportunities for virus transmission to livestock. We showed that connectivity has a strong effect on rabies persistence and that reproductive seasonality and population turnover have only marginal effects compared to connectivity. As connectivity driven by shared feeding areas might not be detectable by genetic analyses of the bats, we proposed the use of a widespread virus persistently infecting bats as a marker to trace connectivity across colonies. Combined, the results presented here provide tools that can be applied to intervene and apply countermeasures to prevent spillover.Item Spatial and temporal dynamics of conifer expansion in southwest Montana(Montana State University - Bozeman, College of Agriculture, 2022) Haygood, Nathaniel Paul; Chairperson, Graduate Committee: Craig Carr; This is a manuscript style paper that includes co-authored chapters.Since the mid-19th century, pinyon-juniper woodlands in western North America have experienced an expansion in range and density and a corresponding degradation in the provision of ecological goods and services including forage production, watershed function, biological diversity, and habitat values. While this is well-documented in other systems, there is little information characterizing shifts in tree range and abundance within the northern extent of these juniper and pine woodlands. The purpose of this research project was twofold: 1) identify and improve understanding of Rocky Mountain juniper and limber pine age distribution and compare these data to other systems, and 2) evaluate understory dynamics along the gradient of woodland development to assess impacts to understory species composition and abundance, as tree densities and range increase. We aged 278 trees across 38 plots in southwest Montana. We recorded soil moisture throughout the growing season (May-July), aspect, elevation, soil texture, herbaceous production and diversity, and tree density and canopy cover from 2019-2021. Greater than 95% of all trees were under 100 years old and the oldest tree (juniper) was 247 years old. Across the study site, limber pine was younger than Rocky Mountain juniper and appeared to prefer different sites. Maximum and mean juniper age was higher on dry sites with high sand content and lower on moist sites with low sand content in the top 15cm of the soil profile. Understory shrub and cool-season perennial grass cover was negatively influenced by heavy tree canopy cover on southwest to southeast aspects. The results from this study indicate 1) limber pine and Rocky Mountain juniper generally occupy different sites, 2) juniper and pine stand age is lower on north facing aspects with coarse soils and higher soil moisture content in late spring and early summer. Currently, increasing conifer dominance on north facing aspects appears to minimally impact cool-season perennial grass cover and production. Comparatively, increasing conifer dominance on south facing slopes may reduce cool-season perennial grass and shrub cover and production. We recommend the inclusion of these findings, as land managers seek to sustain delivery of necessary ecological goods and services.