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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 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 Biophysical environments of the rough fescue/Idaho fescue (Festuca scabrella/Festuca Idahoensis) habitat type of western Montana(Montana State University - Bozeman, College of Agriculture, 1995) Barber, James AustinItem Measuring ecosystem integrity in agroecosystems and rural communities(Montana State University - Bozeman, College of Agriculture, 1997) Knox, David Ernest; Conservation Reserve Program (U.S.)Item Influence of native bunchgrass and invasive forb litter on plant growth in a semi-arid bunchgrass prairie(Montana State University - Bozeman, College of Agriculture, 2006) Hoopes, Carla; Chairperson, Graduate Committee: Cliff Montagne.Litter can influence plant species diversity. I investigated plant litter effects for density, cover, and biomass on common St. Johnswort Hypericum perforatum L., a nonnative- species-group, and a native-species-group. The following hypotheses were tested: litter source would favor species dominant in the litter; the high amount of litter (908 grams) would decrease density more than the moderate amount (454 grams); coarse size litter would decrease density more than fine size; and the effect of litter would depend upon interactions of all three variables. Above-ground plant material was removed from two adjacent sites, one a native bunchgrass prairie (native site), the other infested with St. Johnswort (invasive site). Three-way litter treatments were applied in October 1999 and reapplied in July 2000 in combinations of high- or moderate-amount of litter, native or St. Johnswort species by source, and fine or coarse texture by size. Sampling occurred at peak standing crop July 2000 and 2001. Analysis of variance in 2001 data results follow. St. Johnswort was decreased by its own litter (all P <.06). St. Johnswort and native species were detrimentally influenced more by the high amount of litter than by the moderate amount (all P <.05). Although litter size did not influence St. Johnswort, native species biomass was more detrimentally influenced by coarse size litter than by fine (P <.05). When we added more fine size litter, native species were more detrimentally influenced than when we increased the amount of coarse litter (P <.06). In the invasive site, moderate amounts of coarse native litter decreased St. Johnswort. High amounts of coarse St. Johnswort litter decreased it even more (both P <.05). The opposite effects were found for native species (both P <.05). In the native site, the only treatment that reduced St. Johnswort more than no litter was the high amount of fine St. Johnswort litter (P <.05). The same fine St. Johnswort litter in moderate amounts was the only treatment that did not decrease native species (P <.05). The complexity of litter influence through interactions of amount, source, and size detrimentally and non-detrimentally caused changes to plant species diversity at each site (all P <.05).Item Relationships among geochemical processes and microbial community structure in a unique high-arsenic, sulfidic geothermal spring in Yellowstone National Park(Montana State University - Bozeman, College of Agriculture, 2007) Taylor, William 'Peyton'; Chairperson, Graduate Committee: William P. Inskeep.The metabolisms of chemotrophic microorganisms are linked with the geochemical transformation of redox-active chemical species and mineral precipitation-dissolution reactions in geothermal environments. The objectives of the current work were to correlate the spatial distribution of microbial populations with changes in aqueous geochemistry and mineralogy in a unique Yellowstone National Park (YNP) geothermal spring, and to cultivate thermophilic microorganisms with phylogenetic and metabolic relevance to spring conditions. The geothermal spring (hereafter referenced as Joseph's Coat Spring -JC3) contains the highest reported concentrations of arsenic, antimony and thiosulfate of any geothermal feature studied in YNP. A suite of analytical and molecular approaches including aqueous geochemical and dissolved gas analysis, solid phase characterization, energetic calculations, microscopy and 16S rRNA gene sequence distribution were utilized to correlate specific microbial populations with biogeochemical processes. Predominant geochemical changes observed within the outflow channel were disappearance of methane, dissolved sulfide and ingassing of dissolved oxygen. Oxidation of arsenite was significant within the outflow channel despite the slow ingassing rates of dissolved oxygen. Microbial 16S rRNA gene sequences were determined at locations in the source pool and within the outflow channel.