Theses and Dissertations at Montana State University (MSU)
Permanent URI for this collectionhttps://scholarworks.montana.edu/handle/1/733
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Item Irrigation ditches as novel intermittent stream networks that provide energetic subsidies to terrestrial ecosystems via aquatic insect emergence(Montana State University - Bozeman, College of Letters & Science, 2024) Heili, Nathaniel Maxwell; Chairperson, Graduate Committee: Wyatt F. CrossNon-perennial streams dominate fluvial networks, comprising over half of lotic ecosystems globally. Although little attention has been paid to these systems relative to those that are perennial, perhaps even less is known about the ecology of artificial intermittent streams. In irrigated river valleys, ditches comprise a substantial proportion of surface water networks, but little is known about their relative contributions to lotic habitat, freshwater biodiversity, and ecosystem processes. Because ditches are abundant and permeate arid floodplains, they create new opportunities for cross-ecosystem subsidies through emergence of adult aquatic insects. Here, we mapped the extent of an irrigation ditch network relative to natural surface waters in the Gallatin River Valley, Montana, USA. We also quantified the magnitude, composition, and phenology of aquatic insect emergence in ditches throughout a full irrigation season and compare emergence to nearby natural streams in the valley. We found that non-perennial streams, both natural and artificial, dominated the surface-water network, representing over 70% of total length. Irrigation ditches also constituted 37% and 23% of total length and surface area of all waterbodies in the valley, respectively. Insect emergence production from ditches averaged 32.0 mg m -2 d -1 and exceeded fluxes from nearby natural streams, which contained more classically sensitive taxa (i.e., Ephemeroptera, Trichoptera, and Plecoptera). Ditches varied in water temperature, substrate size, and flow permanence, leading to distinct emergence timing, species composition, and magnitudes of biomass flux. One of the study ditches dried early because of more 'junior' water rights, but this ditch provided the largest emergence subsidy, including a pulse of dipteran emergence at the onset of flow cessation. Annual production from intermittent ditches was ~6 g m -2 y -1 and was comparable to estimates from natural perennial streams. Although our study focused on one river valley of the western US, results suggest that these ecosystems contribute broadly to lotic habitat, heterogeneity, and cross-ecosystem subsidies via aquatic insect emergence. Given increasing demand for water and changes to flow regimes and water management driven by climate change, additional study is needed on these novel and underappreciated artificial ecosystems.Item Hold fast: cultural resilience in the face of climate change(Montana State University - Bozeman, College of Arts & Architecture, 2024) LaCalle, John Christian; Chairperson, Graduate Committee: Hugo R. SindelarThe Cajun Prairie of South Louisiana offers a distinctive lens through which to view the resilience, spirit, identity, and culture of a regional community that is under threat by the impacts of climate change and unsustainable development. Hold Fast explores and captures these struggles using documentary storytelling techniques through the lens of an emblematic subculture in southwest Louisiana in the McNeese State University Rodeo Team. The film presents the challenges of living within a changing climate as the team rebuilds after Hurricane Laura ravaged southwest Louisiana and uprooted their lives in 2020. The short film showcases that in a time of upheaval and widespread displacement, strong cultural identity becomes critical to a community's ability to rebound after disaster. By highlighting the McNeese Rodeo team's journey against the backdrop of Cajun Prairie's challenges, this project seeks to illuminate the interconnectedness of human and environmental stories, showcasing the unwavering spirit of the Cajun community.Item Pollinator conservation and restoration in semi-natural ecosystems(Montana State University - Bozeman, College of Letters & Science, 2022) Glenny, William Robb; Chairperson, Graduate Committee: Laura Burkle; This is a manuscript style paper that includes co-authored chapters.Semi-natural ecosystems are areas with biological and physical characteristics that resemble natural ecosystems but are also affected by anthropogenic disturbances. Semi-natural ecosystems are also areas with high insect pollinator diversity. Land management actions within semi-natural ecosystems may therefore be important to counteract future declines of insect pollinators. However, current restoration strategies for insect pollinator communities are based on evidence from agricultural ecosystems, which have frequent human interventions to ensure plant success, neglect the importance of nesting materials, and primarily benefit generalist species. To inform management actions for the conservation and restoration of insect pollinators in semi- natural ecosystems, I (1) synthesized the current understanding of the effects of common land management actions on insect pollinators on public lands in the US, (2) identified habitat characteristics which structure the taxonomic and functional diversity of bee communities, (3) evaluated the strength of influence of mechanisms associated with diet breadth across groups of bee species and (4) designed a conceptual model which can be used to select flowering plant species to provide food resources for bee communities in semi-natural ecosystems. Management actions that increase the abundance of floral and nesting resources to support bee species from different functional groups are required to conserve and restore insect pollinator communities in semi-natural ecosystems. I found that (1) management actions have positive, neutral, and negative effects on insect pollinators, but research trends vary depending on the taxon and habitat type, (2) the taxonomic and functional diversity of bee communities are structured by the abundance of both floral and nesting resources, (3) patterns of abundance across space and time have a more positive effect on the diet breadth of bumble bee species compared to non- bumble bee species, and (4) wildflower species that receive a high visitation rate and richness, occupy functionally important positions within bee-flower interaction networks, and are spatially and temporally widespread are important to provide bee communities with food resources in semi-natural ecosystems. These wildflower species may be particularly important to include within seed mixes to revegetate semi-natural ecosystems and provide food resources for insect pollinators.Item Roadkill and wildflowers: land-based approaches to settler naturalization(Montana State University - Bozeman, College of Letters & Science, 2022) Zimmerer, Jacob Thomas; Chairperson, Graduate Committee: Kristin T. RuppelSettler-colonialism is the process of severing relationships between people and the land. This ongoing process displaces well-established kinship networks between Indigenous communities and their other-than-human relatives, replacing them with systems of exploitation, settlers, and foreign ecologies. Decolonization, the philosophical counterpart to settler-colonialism, relies on the mending of relationships. This project explores the larger project of decolonization from a settler point-of-view and examines the complexities of navigating a colonial context not entirely of our own making. Settler cultures fail to adequately situate people within the ecosystems of the places they now live, and the ecological and social consequences of this failure have been catastrophic. This piece explores the philosophical underpinnings of settler cultures, provides settler-colonial context, and examines the intersections of colonialism, culture, land, food, and conservation. I propose settler-naturalization as a framework for revitalizing cultures that integrate human communities within ecological systems, and posit that the practices of hunting, scavenging, and foraging are potential pathways towards settler-naturalization. I conclude that there is a need for new stories that embody the concept of naturalization and guide settlers away from narratives of displacement.Item Long-term environmental history of two low-elevation mixed-conifer forests, Mission Valley, Montana(Montana State University - Bozeman, College of Letters & Science, 2021) LaPierre, Kari Richard; Chairperson, Graduate Committee: David McWethyLow elevation mixed-conifer forests are widespread throughout the Northern Rocky Mountains, yet there are few long-term environmental histories from these structurally and compositionally heterogenous ecosystems. We reconstructed >10,000 years of vegetation change, fire activity, and human presence (e.g., pollen, charcoal, biomarkers) for two closed-basin lakes in mixed-conifer forests in the Mission Valley, western Montana. Environmental reconstructions highlight periods of pronounced changes in climate, vegetation, and fire activity. The late glacial period (>18,000-11,000 cal yr. BP) was characterized by post-glacial warming, generally wet conditions, establishment of mixed-conifer forests and infrequent fires. Following an abrupt, short-lived return to Juniper/Douglas fir parkland associated with the Younger Dryas (~12,900-11,500 cal yr. BP), warming temperatures during the early Holocene (11,000-6,000 cal yr. BP) promoted the expansion of open parkland/grasslands and frequent fire activity until cooler summers and warm, wet winters facilitated the development of modern-day closed mixed-conifer forests. Organic biomarker analyses indicate human presence within the Rainbow Lake watershed for millennia c. 7,000-3,000 cal yr. BP. Regional fire frequency increased during this period at Rainbow Lake, suggesting a possible increased role of human influence.Item Interpreting the impact of bioregional curriculum design: measuring sense of place in high school science students(Montana State University - Bozeman, College of Letters & Science, 2019) Dille, Victoria Christine; Chairperson, Graduate Committee: Greg FrancisThe purpose of this study was to gain insights into the relationship between bioregional curriculum design, place-attachment, and ecological awareness in high school science students. Research questions were as follows: (1) Does bioregional curriculum affect place-attachment in high school science students? (2) Does a bioregional approach to studying environmental issues affect local ecological literacy--including shifting ecological awareness and an understanding of local stewardship and conservation topics? (3) What attitudes do students have towards learning experiences informed by bioregional curriculum design? Pre- and post-semester surveys, interviews, performance assessments and a mapping exercise were used as data collection instruments. Data were processed using qualitative and quantitative analysis strategies. The results suggest that students made gains in place-attachment and ecological awareness and had formative learning experiences tied to the curriculum.Item Holistic approach to natural resource and human management : a case study of the Himalayan National Parks in Nepal(Montana State University - Bozeman, 1994) Sherpa, Nima Wangchu; Chairperson, Graduate Committee: Clifford MontagneItem Framing a boundless horizon : a sense of place and the rural adult learner(Montana State University - Bozeman, College of Education, Health & Human Development, 1997) Kittredge, Edrienne LucindaItem Nonindigenous plant species distributions : modeling the role of human disturbances and predicting management responses(Montana State University - Bozeman, College of Agriculture, 2012) Bridges, Melissa Elaine; Co-chairs, Graduate Committee: Lisa J. Rew and Bruce D. Maxwell; Bruce D. Maxwell and Lisa J. Rew were co-authors of the article 'Human disturbance regimes influence the transferability of nonindigenous plant distribution models' in the journal 'Biological invasions' which is contained within this thesis.; Bruce D. Maxwell and Lisa J. Rew were co-authors of the article 'The role of current and historic land uses on the local occupancies of nonindigenous plant species' in the journal 'Landscape ecology' which is contained within this thesis.; Bruce D. Maxwell and Lisa J. Rew were co-authors of the article, 'Nonindigenous population and off target plant community responses to management along an environmental suitability gradient' in the journal 'Journal of applied ecology' which is contained within this thesis.The current paradigm of nonindigenous plant species (NIS) management assumes all NIS populations are invasive and ignores that different populations of the same species have different dynamics and respond differently to perturbations in dissimilar environments. Species distribution models (SDM) can predict spatial patterns of NIS environmental suitability and form a link between management objectives and species distributions. The objectives of this dissertation were to evaluate the utility of SDMs for NIS management. Specifically, the spatial transferability of models, the importance of land uses in explaining NIS distributions, and the relationships between management efficacy and SDM predictions were assessed. The first objective evaluated the transferability of SDMs for two NIS among neighboring regions representing a three-point gradient of human disturbance intensities. The models did not adequately transfer between the two management units representing the least and greatest intensities of human disturbances. This suggested NIS might be distributed differently in response to human disturbances. The second objective compared the relative roles of environmental, current land use, and historical land use variables on explaining occupancies for six NIS. Historical land use explained greater amounts of the variation in NIS occupancies as compared to only environmental variables or environmental plus current land use variables. Land uses currently or previously irrigated for agriculture increased predicted probabilities of occurrence for multiple NIS, including an introduced perennial forage species. The final objective assessed the applicability of SDMs to prioritize NIS populations for management treatments. Herbicide treatments were applied to populations of two NIS located along a gradient of their respective SDM predictions. The effect of herbicide treatment on NIS densities varied either positively or negatively with predicted environmental suitability depending on the specific species. Thus, NIS population responses may be predictable and treatment prioritized using SDM predictions; however, contrasting responses between the two NIS evaluated suggested management should be adapted for species and site specific conditions. This study showed that human disturbance history can affect how NIS are distributed, and, thus, SDMs should be generated from site specific data. Further, SDMs can guide managers as to which NIS populations should be prioritized for management.