Theses and Dissertations at Montana State University (MSU)
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Item African wild dog demography in an ecosystem with reduced prey and dominant competitors(Montana State University - Bozeman, College of Letters & Science, 2021) Goodheart, Benjamin Michael; Chairperson, Graduate Committee: Scott Creel; Scott Creel, Matthew S. Becker, Milan Vinks, Kambwiri Banda, Carolyn Sanguinetti, Paul Schuette, Elias Rosenblatt, Chase Dart, Anna Kusler, Kim Young-Overton, Xia Stevens, Alstone Mwanza and Chuma Simukonda were co-authors of the article, 'Low apex carnivore density does not release a subordinate competitor when driven by prey depletion' in the journal 'Biological conservation' which is contained within this thesis.Conservation of competitively subordinate carnivores presents a difficult challenge because they are limited by dominant competitors. Prey depletion is one of the leading causes of large carnivore decline worldwide, but little is known about the net effect of prey depletion on subordinate carnivores when their dominant competitors are also reduced. African wild dogs are often limited by high densities of dominant competitors, particularly lions. We measured African wild dog density and survival, using mark-recapture models fit to 8 years of data from 425 known individuals in the Greater Kafue Ecosystem, Zambia. The GKE is affected by prey depletion, particularly of large herbivores, and thus the density of lions is significantly lower than ecologically comparable ecosystems. Counter to expectations from mesopredator release theory, wild dog density in GKE was far lower than comparable ecosystems with higher lion and prey density, though annual survival rates were comparable to large and stable populations. Average pack size was small and home range size was among the largest recorded. Our results show that low lion density did not competitively release the GKE wild dog population and we infer that the low density of wild dogs was a product of low prey density. Our results suggest that there is an optimal ratio of prey and competitors at which wild dogs achieve their highest densities. This finding has immediate implications for the conservation of the endangered African wild dog, and broad implications for the conservation of subordinate species affected by resource depletion and intraguild competition.Item Towards a more-than-human geography of the Yellowstone River(Montana State University - Bozeman, College of Letters & Science, 2020) Bergmann, Nicolas Timothy; Chairperson, Graduate Committee: Jamie McEvoy; Jamie McEvoy, Elizabeth A. Shanahan, Eric D. Raile, Anne Marie Reinhold, Geoffrey C. Poole and Clemente Izurieta were co-authors of the article, 'Thinking through levees: how political agency extends beyond the human mind' in the journal 'Annals of the American Association of Geographers' which is contained within this thesis.This dissertation conceptualizes the Yellowstone River, flowing more than 670 miles from its headwaters in the mountains of northwestern Wyoming to its confluence with the Missouri River in western North Dakota, as a more-than-human assemblage. Specifically, this dissertation asks the following overarching research question: How does a more-than-human approach to understanding the Yellowstone River further geographical conceptualizations of human-environment relationships? In order to answer this question, this dissertation investigates the more-than-human aspects of both historical and contemporary environmental conflicts within Montana's portion of the Yellowstone River Basin. Chapter 2 examines the relationship between instream flow water law, Montana Fish and Game, and the Yellowstone River Basin. Drawing from both critical legal geography and political ecology, it furthers understandings of instream flow water law as relationally co-constituted through both human and nonhuman forces. Chapter 2 also traces the influence of Montana Fish and Game's more-than-anthropocentric ethical position on interpretations of the 1973 Montana Water Use Act. Chapter 3 uses a morethan- human approach to examine the relationship between myth and the Yellowstone River. Specifically, this chapter combines existing geographical understandings of myth with theories of assemblage and affect in order to historicize and denaturalize mythic belief in the Yellowstone as the longest undammed or free-flowing river remaining in the United States. Chapter 4 advances more-than-human understandings of political agency through a reframing of human thought as a co-constitutional assemblage of human and nonhuman elements. Relying on a comparative case study approach and qualitative interview data from two Montana communities located along the lower Yellowstone River, this chapter supports its theoretical claims through an embodied and affective analysis of the communities' divergent flood risk perceptions. Chapter 5 closes this dissertation with reflections on the value of using a more-than-human geographical approach.Item A biofilm model that avoids a tragedy of the commons(Montana State University - Bozeman, College of Letters & Science, 2021) Dayutis, Seth Aaron; Chairperson, Graduate Committee: Jack D. DockeryThe study of competition between multiple species is of great significance in biology. Competitive behavior is often observed to occur in biofilms and understanding cooperation between multiple species in a single biofilm is the center of much research. The species that grow in biofilms are frequently studied in chemostats, which have a rich history in mathematical modeling. In this thesis, a review of a mathematical chemostat model is presented in which a tragedy of the commons occurs. The chemostat model is then developed into a biofilm model to see if a tragedy occurs in a biofilm under similar conditions. The biofilm and chemostat model consist of two species, a cooperator and a cheater. The cooperator produces an enzyme that combines with a substrate to produce a nutrient. The nutrient is then consumed by the cooperator and cheater. The cooperator is at a disadvantage since it must allocate some of its nutrient uptake towards enzyme production. A one dimensional biofilm model is developed with reaction advection equations governing the behavior of the species and reaction-diffusion equations governing the behavior of the substrate, nutrient ,and enzyme. A set of numerical methods is then outlined on how to solve the system of equations. It is found that a tragedy of the commons is avoided in the biofilm and both species can persist when numerical simulations are run for a finite amount of time. It is then argued that the cooperative behavior exhibited by the two species is a stable equilibrium by approximating the steady state solutions. Further evidence is provided for the existence of a stable equilibrium by perturbing the system and finding that the perturbed system tends back to the equilibrium. Finally, the eigenvalues of the discretized linear system are computed and the results suggest that either the equilibrium is stable or moves away from the equilibrium slowly.Item Temporal dynamics of Escherichia coli and the microbiome(Montana State University - Bozeman, College of Letters & Science, 2020) Martinson, Jonathan Nathan Vernon; Chairperson, Graduate Committee: Seth Walk; Seth T. Walk was a co-author of the article, 'Escherichia coli residency in the gut of healthy human adults' submitted to the journal 'EcoSal plus' which is contained within this dissertation.; Nicholas V. Pinkham, Garrett W. Peters, Hanybul Cho, Jeremy Heng, Mychiel Rauch, Susan C. Broadaway and Seth T. Walk were co-authors of the article, 'Rethinking gut microbiome residency and the enterobacteriaceae in healthy human adults' in the journal 'The ISME journal' which is contained within this dissertation.; Nicholas V. Pinkham and Seth T. Walk were co-authors of the article, 'Phenotypic predictors of Escherichia coli residency in the gut of healthy human adults' submitted to the journal 'Applied and environmental microbiology' which is contained within this dissertation.Over the past two decades, our understanding of the gut microbiome has increased dramatically. However, most studies involving healthy adults have relied almost exclusively on cross-sectional design, negating the changes occurring within an individual's microbiome through time. With this, we performed a small longitudinal study over a period of ~2 years with a cohort of 8 healthy adults. By sequencing the DNA encoding the 16S ribosomal RNA gene, we assessed the community level change in this cohort through time. Similar to previous findings, we found that using these methods there was remarkable stability through time with nearly 50% of the microbiome remaining the same throughout the study period in the participants. However, analysis of 16S ribosomal RNA sequences limits taxonomic resolution. By cultivating members of the Enterobacteriaceae, we found that turnover at the clone-level (below the species level) was common. Within the Enterobacteriaceae, Escherichia coli was the most numerically dominant species and most often observed as a long-term member of the gut (i.e. resident). Longitudinal analysis of Escherichia coli revealed that some phylogenetic groups within the species are more often long-term residents than other phylogroups. We next assessed the means by which the resident E. coli were capable of establishing and maintaining themselves in the gut. We found that residents were much more likely to produce antagonism (inhibition of other clones) than the E. coli that did not reside in the gut long-term.Item Feeding ecology and food-web interactions of the fish assemblage in the upper Missouri River and lower Yellowstone River with an emphasis on pallid sturgeon conservation(Montana State University - Bozeman, College of Letters & Science, 2018) Dutton, Adeline Jean; Chairperson, Graduate Committee: Christopher S. Guy; Christopher S. Guy was a co-author of the article, 'Diet overlap and gape size of pallid sturgeon and shovelnose sturgeon in the Missouri River and Yellowstone River' submitted to the journal 'Journal of applied ichthyology' which is contained within this thesis.; Christopher S. Guy and Eric A. Scholl were co-authors of the article, 'Quantitative food-web linkages among primary, secondary, and tertiary consumers in the upper Missouri River and lower Yellowstone River' submitted to the journal 'Journal of freshwater ecology' which is contained within this thesis.A conservation propagation program started in the late 1990s for the endangered Pallid Sturgeon Scaphirhynchus albus because the species was not recruiting in the Missouri River. Stocking has been successful and several studies have suggested that the survival of stocked Pallid Sturgeon in the upper Missouri River is relatively high. Stocking of hatchery-origin Pallid Sturgeon may have created an uncharacteristic population structure, which could lead to intraspecific and interspecific competition between juvenile Pallid Sturgeon, Shovelnose Sturgeon, and other fish species in the Missouri and Yellowstone rivers. The purpose of this study was to describe the diets of Pallid Sturgeon and Shovelnose Sturgeon, determine if gape size differed between species, and assess diets of many secondary and tertiary consumers to describe the food web of the upper Missouri and lower Yellowstone rivers. Pianka's index of diet overlap was highest in segments near Fort Peck Dam in the Missouri River. Diet overlap was low in the Missouri River below the confluence with the Yellowstone River and in the Yellowstone River. Gape size was slightly different between Pallid Sturgeon and Shovelnose Sturgeon suggesting it was not the mechanism for the shift to piscivory in Pallid Sturgeon. Chironomidae were the most abundant primary consumer in the upper Missouri River and lower Yellowstone River. Hydropsychidae were not abundant in either river system, but were frequently consumed by Goldeye, Channel Catfish, Shovelnose Sturgeon, and Stonecat in the Missouri River and Shovelnose Sturgeon in the Yellowstone River. Emerald Shiner were the most abundant secondary consumer in both rivers and the most frequently consumed secondary consumer by Pallid Sturgeon, in the Missouri River. In addition, Pallid Sturgeon in the Missouri River consumed Channel Catfish, Shovelnose Sturgeon, and either Sicklefin Chub or Sturgeon Chub. In the Yellowstone River, Pallid Sturgeon consumed Channel Catfish, Scaphirhynchus spp., and Stonecat. These results provide a foundation into key linkages among predators and prey to better understand the effects of stocking Pallid Sturgeon in the upper Missouri River and lower Yellowstone River.Item Risky business: dealing with risk in a predator - prey community(Montana State University - Bozeman, College of Letters & Science, 2017) Droge, Egil Dag; Chairperson, Graduate Committee: Scott Creel; Scott Creel, Matthew S. Becker and Jassiel M'soka were co-authors of the article, 'Spatial and temporal avoidance of risk within a large carnivore guild - predator avoidance by predators' in the journal 'Ecology and evolution' which is contained within this thesis.; Scott Creel, Matthew S. Becker and Jassiel M'soka were co-authors of the article, 'Measuring the 'landscape of fear': risky times and risky places interact to affect the response of prey' in the journal 'Ecology and evolution' which is contained within this thesis.; Scott Creel, Matthew S. Becker, David A. Christianson and Fred G.R. Watson were co-authors of the article, 'Response of wildebeest (Connochaetes taurinus) movements to spatial variation in long term risks from a complete predator guild' which is contained within this thesis.The Liuwa ecosystem has several ecological properties that affect interactions among large predators, with lions and hyaenas as dominant species and African wild dog and cheetah as subordinate species, and between predator and prey. First, the vegetation structure is highly uniform and typified by open grasslands with good visibility over long distances. Secondly the prey community is heavily dominated by wildebeest, with much lower numbers of zebra, oribi and other species. These characteristics combined with GPS data on a fine spatial scale, and a large observational dataset on both predators and prey enabled us to focus on several little-studied questions about the effects of predation risk in the wild. Interspecific competition between predators can be a strongly limiting force for subordinate predators like cheetahs and African wild dogs. Both species use niche partitioning to reduce the risk of dangerous interactions in different ways that appear to have ramifications for coexistence. Wild dogs showed more dietary and temporal overlap with dominant competitors while cheetahs combine divergence in diet, temporal avoidance and reactive local spatial avoidance to coexist with lions and hyenas in areas of high prey density, even in open habitats. These results provide new insight into the conditions under which partitioning may not allow for coexistence of African wild dog, while it does for cheetah, with dominant predators making wild dogs more prone to competitive exclusion (local extirpation), particularly in open, uniform ecosystems with simple prey communities. Focusing on predator-prey relationships the overall the conclusion is that the assessment of risk by animals is a very fine-tuned process. Our results confirm that both the risky places hypothesis (LT risk) and the risky times hypothesis (ST risk) are important, leading to both reactive and proactive responses. Critically, these effects do not act independently in their effects on the strength of antipredator responses. This interaction presents challenges for the design of research on risk effects. An effect of ST risk could be masked by unmeasured variation in LT risk (or vice versa), and an effect of ST risk might be caused by unmeasured variation in LT risk (or vice versa).Item Spotted hyaena survival and density in a lion depleted ecosystem : the effects of competition between large carnivores in African savannahs(Montana State University - Bozeman, College of Letters & Science, 2015) M'soka, Jassiel Lawrence Juma; Chairperson, Graduate Committee: Scott Creel; Scott Creel, Mathew S. Becker and James Murdoch were co-authors of the article, 'Ecological and anthropogenic effects on the density of migratory and resident ungulates in a human-inhabited protected area' submitted to the journal 'African journal of ecology ' which is contained within this thesis.; Scott Creel, Mathew S. Becker and Egil Droge were co-authors of the article, 'Spotted hyaena survival and density in a lion depleted ecosystem: the effects of competition between large carnivores in African savannahs' which is contained within this thesis.Competition is considered an important factor for large carnivore population dynamics, but the manner in which interspecific competition impacts these species are not well understood. This lack of knowledge is due to the ongoing declines of large carnivores, the loss of intact large carnivore guilds, the complexity of competitive relationships and how they can be impacted by ecological and anthropogenic factors. In light of rapid declines of carnivore populations across the globe, understanding how interspecific competition limits large carnivores is an important component for the management and conservation of these species. Using data from 233 individuals in five clans and capture-recapture robust design models we estimated the survival and density of spotted hyaena in 5 clans in the Liuwa Plain, where their main competitor, the African lion was reduced to a single individual. We tested for the effects of settlements, prey density, competition with lions and hyaena clan size on the mean hyaena survival. The average population size during the duration of study was 151.2 + or = 5.9(SE) individuals. Population size fluctuated through time with the seasonal fluctuations of the main prey species, the blue wildebeest. Mean annual survival across all age classes was 0.93 (95%CI: 0.39 - 0.99). We found no detectable effects of variation in hyaena clan size, prey density, local variation in utilization by lions, or proximity to people on survival. We also estimated the densities of wildebeest, oribi and zebra, the main prey species for the carnivores in the system using distance sampling methods. We tested for the effects of variables in three classes: environmental (year, season, vegetation, grass height, burn, water presence), predation risk (hyaena density), and anthropogenic (distance to park boundary and settlements). Densities ranged from 6.2 - 60.8 individuals km superscript -2 for wildebeest, 1.1-14.5 individuals km superscript -2 for oribi, and 1.8-8.1 individuals km superscript -2 for zebra. Results reveal resource partitioning among ungulate species and indicate that predation risk and proximity to humans affect ungulate distributions with implications for managing migrations in the Greater Liuwa Ecosystem. They suggest that the maintenance of native prey populations allows coexistence between humans and large carnivores in Liuwa Plain National Park.Item Investigating the potential of using R* theory to manage nonindigenous plant invasions(Montana State University - Bozeman, College of Agriculture, 2004) Mangold, Jane Marie; Chairperson, Graduate Committee: Roger L. Sheley.R* theory has been proposed as a mechanism for plant community dynamics, but the theory is poorly tested and has not been developed into a principle for management. This theory states that the outcome of succession is based on the ability of a plant to sequester a limiting resource when it is below the uptake level of neighboring species. ' R* is the resource level a species requires to persist in an environment, and the species with the lowest R* dominates over time. Knowledge of the R*s for species within a plant community could lead to effective weed management with predictive capabilities. The overall objective of this research was to explore R* theory’s potential for managing nonindigenous plant invasions on western rangeland. Specific objectives included: 1) determining the most influential limiting resource for a western rangeland plant community, 2) determining R*s for two native species and a nonindigenous invader, 3) predicting the outcome of succession based upon species’ R*, and 4) altering resource availability to favor desirable species based upon their R*. Three studies were conducted beginning in 2000. For Study 1, availability of essential plant resources were altered and the plant community was sampled for a biomass increase. Results of Study 1 suggested nitrogen was the major limiting resource for the dominant functional group. Study 2 was a greenhouse study that attempted to quantify the R* for nitrogen for three species. The R* for annual sunflower was 0.6 ppm NO3-N; the R* for bluebunch wheatgrass was less than 0.6 ppm NO3-N; and spotted knapweed’s R* was between 0.4 and 0.6 ppm NO3-N. Two- and three-species mixtures suggested estimated R*s accurately predicted the outcome of competition between natives, but not with natives and spotted knapweed. Study 3 tested succession dynamics under natural and nitrogen-manipulated conditions. Soil nitrogen was altered by nitrogen and sucrose additions. Annual sunflower did not persist. Spotted knapweed biomass increased with nitrogen addition but did not decrease with carbon addition, even though soil NO3-N was below its R*. Bluebunch wheatgrass appeared unaffected by nitrogen manipulation, but soil NO3-N concentration was not decreased below its R*.Item A reaction diffusion model for competing pioneer and climax species(Montana State University - Bozeman, College of Letters & Science, 1998) Brown, Sharon LynnItem Development of occupancy surveys for mountain ungulates(Montana State University - Bozeman, College of Letters & Science, 2013) O'Reilly, Megan; Chairperson, Graduate Committee: Robert A. GarrottBighorn sheep (Ovis canadensis canadensis) and mountain goats (Oreamnos americanus) overlap in broad food and habitat requirements. In places where mountain goats are non-native there are concerns over potential competition between the two species. The southern Gallatin Mountain range, within and adjacent to the northwest boundary of Yellowstone National Park has both native bighorn sheep and non-native mountain goats. Existing observations of both species for this area vary in spatial precision and there are no records of where observers looked for animals but did not detect them. To gain a better understanding of the relationship between bighorn sheep and mountain goats and their habitat, it is necessary to understand resource selection and the extent of overlap in resource use at fine spatial and temporal scales. I used logistic regression to relate existing presence-only bighorn sheep and mountain goat data for this area to landscape features I expected would be important to both species. Using resulting coefficient estimates, I constructed a relative habitat suitability map and used it to define four survey regions within the study area. The crew of four spent 113 observer days afield and hiked 210 miles recording occupancy data for both mountain ungulates within these four survey regions. Observers surveyed 6,603 100 x 100 meter grid cells, with 15 groups of bighorn sheep and 34 groups of mountain goats observed during surveys. Because there were more mountain goat observations available, I used only mountain goat data to conduct formal occupancy analyses. Mountain goat occupancy was positively associated with ruggedness at the 100 meter scale and there was an important interaction between distance to escape terrain and tree cover at the 500 meter scale. As the distance to escape terrain increased mountain goats were less likely to occupy treed areas. The ruggedness index used in my presence-only modeling effort was based on the rate of change in slope. By using a ruggedness index which included changes in slope and aspect I improved model performance. This research demonstrates the feasibility of conducting occupancy surveys in mountainous terrain and provides interesting biological insights regarding mountain goats and their habitat.