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Item Remote sensing for wetland restoration analysis: Napa-Sonoma Marsh as case study(Montana State University - Bozeman, College of Agriculture, 2019) Byrne, Charles; Chairperson, Graduate Committee: William KleindlHuman-caused ecosystem change and habitat loss is a major worldwide concern. Wetland loss has been remarkable worldwide and in the US. In the San Francisco Bay system, the largest estuary on the eastern rim of the Pacific Ocean and a biodiversity hotspot, more than 90 percent of the wetlands have been lost to urban development, salt production and agriculture, a loss that primarily occurred in the century following 1850. Restoration is our primary mechanism for confronting this challenge. While wetland restoration design has advanced dramatically since the early designs of the 1980s, restoration analysis and evaluation remain challenges that until now have wholly or primarily required on-site sampling. This is a major challenge for larger restoration projects, such as the Napa-Sonoma Salt Marsh restoration in California. Previous studies have indicated that the Normalized Difference Vegetation Index (NDVI) has been used in some restoration analyses with apparent success, but data is limited. To better understand its potential, this study examines issues in restoration analysis in the context of wetland restorations. By comparing pre- and post-restoration remote sensing data, I found that two sites in the Napa-Sonoma Marsh restoration demonstrated mixed NDVI results and that changes depended on subarea and whether median or maximum NDVI was analyzed. The mixed results are explained by several factors: the inherent limitations of NDVI; the large restoration size; the fact that wetlands, less vegetated, present special challenges for analysis; and the fact that it is early in the post-restoration period. The case study supports the use of remote sensing and GIS for restoration analysis and evaluation, but also emphasizes their current limitations. Many of these limitations, which hinge on the complexity of the potential data involved, are likely to be addressed in the next generation as the relevant technology continues to develop.Item Multi-scale assessment of semi-arid vegetation communities: climate, disturbance, and environment as spatiotemporal drivers of phenology and composition(Montana State University - Bozeman, College of Agriculture, 2021) Wood, David Jonathan Adrian; Chairperson, Graduate Committee: Scott Powell and Paul C. Stoy (co-chair); This is a manuscript style paper that includes co-authored chapters.Ecosystems processes and functions include hierarchical and complex drivers. Assessing drivers of variation at multiple scales therefore helps predict biotic responses and improves our overall understanding of ecosystems. For example, the seasonal cycle and duration of events, phenology, represents a foundational process sensitive to changes in climate, and has cascading impacts across the ecosystem. The long-term record and expansion of remote sensing techniques provides an opportunity to both assess phenological changes through time at broad spatial extents while also assessing variability at finer spatial scales. At regional extents, satellite-based measurement can provide key insights into community level shifts, while finer scaled techniques such as unpiloted aerial vehicles (UAVs), spectral sensors, and automated digital cameras (phenocams) can investigate pattern differences at centimeter scales (i.e., plant and functional groups). I analyzed the year to year and spatial variability of phenology and composition of rangeland systems over multiple spatial scales to explore interrelated aspects of ecosystem functions. I used the AVHRR satellite record of phenology to examine spatial and temporal variability in phenological drivers and to identify key drivers and differences between the phenology of communities, including the role of ecological memory, the legacy impact of prior climate over months to years. In addition, by employing UAVs, spectral sensors, and phenocams I investigated the pattern and influence of heterogeneity on the phenology of grasses and shrubs. Finally, I investigated the interaction of multiple disturbances on the relative proportions of vegetation functional groups within a community. Key findings include productivity tradeoffs, where higher annual temperature increased peak but decreased growing season long productivity; climate conditions from the prior season and up to four prior years influenced date and productivity phenological measures; near earth sensors can characterize phenological variation at the microsite level; and there is an interactive effect of fire and development disturbance on non-native annual grass expansion. The vegetation of U.S. rangelands is projected to have consequential impacts from climate change, especially summer drying, and these impacts can be better quantified by including antecedent conditions and incorporating microsite differences into predictive models.Item Long-term response of willow to beaver reintroduction and moose browsing in the southern Absaroka-Beartooth Wilderness(Montana State University - Bozeman, College of Agriculture, 2022) Dines, Rachael Helen; Chairperson, Graduate Committee: Bok SowellWillow is an important component in the southern Absaroka Beartooth Wilderness (ABW) riparian areas because it provides critical beaver habitat and is an essential food source for moose populations. Forest Service managers have monitored long-term trends in willow condition and herbivore populations in the southern ABW. Beavers were extirpated in the mid-1900's and then reintroduced beginning in 1986. Moose numbers increased in the early 1900's and willow over-browsing followed until the population declined after habitat loss from the 1988 Yellowstone fires. The objective of this study was to examine willow condition in response to changes in beaver and moose populations in the southern ABW. I used annual stream-side surveys to record the number and location of beaver colonies from 1986 to 2021 and aerial imagery to describe changes in willow canopy cover. I used a binomial regression to evaluate the relationship between willow canopy cover and beaver colony density and longevity to estimate if long-term beaver presence increased willow canopy cover. I used linear regression to analyze indices of moose relative abundance, willow plots recording height and browsing, and a long-term browsing exclosure to evaluate the effect of moose population trends on willow height. Beaver have remained at carrying capacity over the last 20 years, and average willow canopy cover increased from 16% in 1981 to 37% in 2019. The probability of willow occurrence increased the longer beaver occupied an area and with colony density (colonies/km). Moose relative abundance declined from 1987 to 2021, while average willow height increased from 113cm in 1988 to 190cm in 2021 and browsing decreased from 53% in 1989 to 3% in 2021. Browsing was an important factor limiting willow height. Moose abundance had a positive linear relationship with average browsing pressure and negative linear relationship with average willow height. This study shows that the southern ABW was able to recover from historic over-browsing and beaver extirpation. The long-term effects of beaver reintroduction and reduced moose numbers in a historically degraded environment enhanced willow, indicating that under the right circumstances, willow communities have the potential to recover from a previously degraded state.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 Positive effects of ecosystem engineers on stream communities and processes(Montana State University - Bozeman, College of Letters & Science, 2022) Tumolo, Benjamin Bartley; Chairperson, Graduate Committee: Lindsey Albertson; This is a manuscript style paper that includes co-authored chapters.Ecosystem engineering is a process by which organisms modify habitat characteristics and influence community structure and ecosystem function. These engineer-mediated habitat modifications often have positive effects on community members by improving or creating novel habitats that ameliorate harsh conditions. Despite the far-reaching consequences of such positive interactions, most of what we know about ecosystem engineering is limited to marine or terrestrial habitats and focused on sessile, long-lived foundation species. Less recognition has been given to mobile, smaller bodied, and shorter-lived insect engineers within freshwater ecosystems. This knowledge gap is significant as freshwaters are one of the most threatened habitats globally, and freshwater insects are experiencing alarming rates of decline. My dissertation seeks to uncover how organism interactions modify physical and resource environments in ways that can affect community structure and ecosystem function. My objectives were to: 1) synthesize literature to develop a conceptual framework aimed at describing how two distinct mechanisms of positive interactions scale over time and space; 2) measure how net-spinning caddisfly (Hydropsychidae) engineers and their abandoned engineering structures differentially facilitate communities; 3) quantify the importance of beneficiary functional traits and environmental gradients in determining the strength of facilitation between caddisflies and invertebrate communities; and (4) test how caddisflies can generate hotspots of community assembly and ecosystem function. I found that caddisfly ecosystem engineers and their abandoned structures increased invertebrate colonization; however, occupied structures supported greater colonization of Chironomidae compared to abandoned structures. Additionally, I found that the strength of caddisfly facilitation increased with increasing elevation and was dependent on small-bodied beneficiaries. Furthermore, I found that caddisfly engineers generated ecological heterogeneity by aggregating both resources and consumers, with consequences for elemental cycling. Overall, my dissertation emphasizes the role that biology can play in modifying environments and how these alterations can positively influence biological communities with consequences for ecosystem function.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 Climate-fire-vegetation dynamics in the Greater Yellowstone Ecosystem: recent trends and future projections in a changing climate(Montana State University - Bozeman, College of Letters & Science, 2020) Emmett, Kristen Dawn; Co-chairs, Graduate Committee: Benjamin Poulter and David Roberts; Katherine M. Renwick and Benjamin Poulter were co-authors of the article, 'Disdentangling climate and disturbance effects on regional vegetation greening trends' in the journal 'Ecosystems' which is contained within this dissertation.; Katherine M. Renwick and Benjamin Poulter were co-authors of the article, 'Adapting a dynamic vegetation model for regional biomass, plant biogeography, and fire modeling in the western U.S.: evaluating LPJ-GUESSLMFIRECF' submitted to the journal 'Ecological modelling' which is contained within this dissertation.; Benjamin Poulter was a co-author of the article, 'Processed-based modeling approaches for climate-vegetation-fire feedbacks in the Greater Yellowstone Ecosystem' which is contained within this dissertation.Climate change threatens to change forested ecosystems and wildfire characteristics across the globe. For the Greater Yellowstone Ecosystem (GYE), under future warming temperatures, wildfire activity is expected to increase and the suitable habitat for many dominant tree species is expected to shrink. Previous studies predict large high severity fires to occur more frequently, potentially so frequent that forests are unable to grow old enough to produce seeds and self-regenerate. Studies of suitable climate spaces show that previously habitable areas may become too warm or dry to support common GYE trees. The first goal of this dissertation was to use vegetation images from satellites to detect recent changes in forest productivity in the GYE, and then determine the relative importance of recent climate and disturbance observations in explaining these changes. We found that areas with detected increases in plant growth, or 'greening' trends, were associated with forested areas regenerating after wildfire. Detected decreases in plant growth, or 'browning' trends, were associated with areas that had recently burned. Historically dry areas with recent increases in precipitation were associated with greening trends. Warming of 0-2 °C was associated with greening trends, while greater increases in temperature (>2 °C) were correlated with browning trends. The key take-away is although forests in the GYE are usually considered temperature limited, changes in precipitation may be more important than previously thought. The second goal of this dissertation was to adapt a global vegetation computer model for regional applications to simulate forests and wildfire dynamics, ultimately to run simulations under future climate conditions to predict how forest extent and composition may change. Life history characteristics and climate limitations were aquired for the dominant GYE plant types to dictate their establishment, growth, competition, and mortality in the new model. Before running future simulations, it is required to evaluate how well the model represents current conditions. Adding new equations that calculate the initiation, spread, and effects of crown fires was required to reproduce recent vegetation abundance, distribution of plant types, and fire activity in the GYE. Methods, expected results, and implications of running future simulations are described in Chapter 4.Item Evaluation of methanotrophic activity and growth in a methanotrophic-heterotrophic co-culture(Montana State University - Bozeman, College of Engineering, 2021) Kilic, Ayse Bengisu; Chairperson, Graduate Committee: Ellen G. Lauchnor; Erika J. Espinosa-Ortiz, Brent M. Peyton and Ellen Lauchnor were co-authors of the article, 'Methane-based bioreactor configurations in value-added product development: a review' submitted to the journal 'Journal of bioscience and bioengineering' which is contained within this thesis.; Erika J. Espinosa-Ortiz, Brent M. Peyton and Ellen Lauchnor were co-authors of the article, 'Evaluation of methanotrophic activity and growth in a methanotrophic-heterotrophic co-culture' submitted to the journal 'Engineering in life sciences' which is contained within this thesis.Methane is a potent greenhouse gas (GHG) and accounts for 20-30% of the GHG emissions globally. In nature, methane is utilized as a sole carbon and energy source by a group of bacteria referred to as methanotrophs. Methanotrophs have been reported to have the ability to form close associations with other microorganisms such as heterotrophic bacteria in the environment. Therefore, understanding methanotrophic activity and growth in a microbial consortium with heterotrophic bacteria is of interest from an environmental and biotechnology perspective. In this study, a methanotroph; Methylocystis sp. NLS7 and a heterotrophic bacterium, Pseudomonas chlororaphis, were co-cultivated in a methane-fed bioreactor with a dialysis membrane device used to separate the species physically. It was hypothesized that the co-culture would exhibit enhanced methanotrophic activity and microbial growth of NLS7 in NLS7- P. chlororaphis co-culture. The methane-oxidation rate and microbial growth rate of NLS7 were evaluated as a functional response variable to the presence of P. chlororaphis. In addition, the effects of NLS7 growth were evaluated on the growth of P. chlororaphis. Our findings indicated that the presence of P. chlororaphis does not have any beneficial effects on Methylocystis sp. NLS7 activity and growth. However, the growth of P. chlororaphis in the co-culture with solely methane as a carbon source indicated that P. chlororaphis is likely gaining carbon and energy from by-products of methane oxidation by Methylocystis sp. NLS7 since P. chlororaphis could not utilize methane as a carbon and energy source. The results of this study give us an important insight into the activity and the growth of methanotrophic consortia in methane-driven ecosystem.Item Plant diversity of Mediterranean-type ecosystems with an emphasis on cultivated species(Montana State University - Bozeman, College of Agriculture, 2019) Botros, Mina Habib; Chairperson, Graduate Committee: Matthew LavinThe Mediterranean Basin is an important biodiversity hotspot. Unfortunately, only 5% of its original vegetation remains intact because people have managed and transformed the landscape for the past 2000 years. In the last century, humans overused the semi-natural habitats which had a negative impact on the area more than earlier times. This is in addition to the mechanization of agriculture which had a negative impact on the area as well (Puddu, Falcucci, and Maiorano 2011). Mediterranean-type ecosystems (MTEs) are as plant diverse as tropical ecosystems. This biodiversity is larger than expected considering the relatively high latitude and the low productivity of the region. This makes these areas a good case study to examine the processes affecting plant diversity. Five MTEs are described as biodiversity hotspots due to the high numbers of endemic plant species. Scientists are working to decrease the biodiversity loss in the Mediderranean area. Here we will discuss biodiversity, cultivated species, and threats to Mediterranean-type ecosystems. Moreover, we will present the adaptation of these species to biotic and abiotic stresses, in addition to scientists' efforts to develop cultivars well-adapted to these stresses.Item An interpretive center for the Greater Yellowstone ecosystem(Montana State University - Bozeman, 1991) Harger, Keith; Chairperson, Graduate Committee: Henry E. Sorenson