Scholarworks
ScholarWorks is an open access repository for the capture of the intellectual work of Montana State University (MSU) in support of its teaching, research and service missions. MSU ScholarWorks is a central point of discovery for accessing, collecting, sharing, preserving, and distributing knowledge to the Montana State University community and the world.
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Recent Submissions
'Hypertemporal' remote sensing of plant function: a comparison of phenocam and geostationary operational environmental satellite NDVI data products
(Montana State University - Bozeman, College of Agriculture, 2019) Douglas, James Thomas; Chairperson, Graduate Committee: Paul C. Stoy
Ongoing climate warming is changing the seasonality of plant canopy function, but common approaches to explore these changes via polar-orbiting satellites often miss rapid canopy transitions due to infrequent observations. I explored the ability of satellites designed for studying weather systems, namely The Geostationary Operational Environmental Satellite (GOES), to track plant canopy status on time scales of minutes. With new capabilities to remotely sense in the infrared, the GOES weather satellites now have the capability to detect photosynthetic activity. Satellite observations of the normalized difference vegetation index (NDVI) are compared against near-surface phenological camera ("PhenoCam") observations from the National Ecological Observation Network (NEON, Inc.) at six sites every 15 minutes for one week in April 2019. Diurnal trends across both observation platforms showed the expected diurnal parabolic structure in NDVI with critical differences in NDVI magnitude between PhenoCams and GOES observations. One tailed T-test results show that there is variability between methods when measuring NDVI, with P-values less than 0.05 in all cases. This was anticipated due to correction factors needed for PhenoCam NDVI observations. However, additional variability can be attributed to other areas such as cloud cover, plant type, and heterogeneity. My proof-of-concept study demonstrates that raw NDVI data from both methods are often comparable, which lends credit to the notion that NDVI can be accurately observed from space at high (up to five minute) temporal resolution. With current research underway on the topics of atmospheric corrections and further surface validation, GOES has the potential to observe land surface attributes at up to 5-minute intervals across entire hemispheres for identifying phenology, disturbance and other vegetation dynamics in real time. With two hypertemporal methods at different spatial scales recently introduced, the research is primed to move towards a real time understanding of plant canopy function across the United States.
The role of canopy tree diversity on understory plant richness and tree seedling abundance in a Pinus strobus forest in the southeastern U.S.
(Montana State University - Bozeman, College of Agriculture, 2019) Davis, Stephanie Ann Morrow; Chairperson, Graduate Committee: Lisa Rew
The goal of my project was to determine whether diversity in the canopy layer of a Pinus strobus dominated, mixed mesic forest in the piedmont of North Carolina showed a relationship to 1) understory richness and 2) tree seedling abundance. Forty plots were randomly selected at White Pines Nature Preserve, in Sanford, North Carolina for the study. For each plot, understory, species and tree seedling richness and density were recorded. Explanatory variables included canopy tree species richness, density and cover, total diameter at breast height (dbh) and environmental data including soil type, distance to nearest trail, and elevation. Diversity was calculated using the Simpson Index of Diversity (1-D) to show the effect of dominance in the canopy. Understory richness showed a decreasing pattern with increasing canopy diversity (p= 0.0783), suggesting a negative effect of canopy diversity on understory richness. Likewise, tree seedling abundance showed a significant negative response to canopy richness (p= 0.0146) and to all soils types (both positive and negative response). Total canopy tree basal area (diameter of tree at breast height) showed a positive relationship (p= 0.0514) to canopy species diversity (with functional similarity), which supports research showing complementarity between functionally-similar canopy tree species. Overall, results for this study suggest that, in a historically Pinus strobus-dominated forest, although greater canopy tree basal area is related to higher canopy diversity, understory richness is negatively affected by higher canopy diversity, and tree seedling abundance is negatively affected by higher canopy species richness.
Spatial analysis of the recovery of submerged aquatic vegetation in the Hudson river estuary following the 2011-2012 hurricane seasons
(Montana State University - Bozeman, College of Agriculture, 2019) Carroll, Sean Michael; Chairperson, Graduate Committee: Scott Powell
Submerged aquatic vegetation (SAV) is a critical habitat found in estuarine ecosystems throughout the world. SAV performs a multitude of ecosystem functions ranging from water quality improvement to habitat for macroinvertebrates and juvenile fish, and acts as a significant contributor to dissolved oxygen throughout the estuarine system. In the Hudson River Estuary (HRE), native SAV beds have been greatly reduced or altered by threats such as sedimentation, water quality issues, and the spread of invasive aquatic plants, as well as by disturbance from natural events such as large-scale storms. In 2011 and 2012, three hurricanes made landfall in the northeastern United States, having a tremendous impact on the Hudson River and the Hudson Valley region as a whole. SAV in the estuary was impacted by both storm surge as well as significant sediment deposition from the river's tributaries. However, in the wake of these events, there is uncertainty about the spatial patterns of SAV loss and recovery, and how these patterns are affected by the hydrology and physical characteristics of the river. Therefore, my study seeks to address this knowledge gap by investigating the impacts of these storms on SAV spatial patterns and the influence of SAV proximity to shoreline, tidal wetlands, and persistent "colony" SAV beds. I investigated these effects by analyzing overall (whole system) SAV recovery, the spatial patterns of recovery, and the correlation of recovery to prior SAV coverage and proximity to these features. Analysis was done using three years of remotely-sensed SAV GIS data, and was done at three different spatial scales. SAV coverages were determined at each scale for all three years and areal-change and percentage-change were calculated. Distance to the three aforementioned features was calculated for the fine-scale analysis. The results suggest that there was significant SAV loss river-wide between 2007 and 2014, followed by significant recovery between 2014 and 2016. Loss between 2007 and 2014 was greatest in the most upstream approximately 100 km of the river, likely a result of proximity to the Mohawk River, a major tributary and large sediment source during the storms. SAV recovery showed a similar pattern, occurring most in these upstream reaches. Distance from shoreline, tidal wetlands, and persistent SAV beds had varying impacts on SAV loss and recovery. The findings of this study help to elucidate both the potential impacts on the magnitude and patterns of vegetation loss following a large storm event and subsequent sediment flux, as well as the recovery potential of this vegetation during 'normal' years. Such information can help inform future biological studies of the HRE and watershed management decision-making.
Water quality and physical parameters of Barnegat Bay after Hurricane Sandy
(Montana State University - Bozeman, College of Agriculture, 2019) Rodenberg, Taylor; Chairperson, Graduate Committee: William Kleindl
Barnegat Bay is a coastal water body located off of the east coast of New Jersey. The bay is bordered by an estuary system to the west and barrier island and the Atlantic Ocean to the east. The bay is an important ecosystem for dozens of species of invertebrates, fish, mammals, birds, and amphibians, and provides millions of dollars in revenue for surrounding towns in tourism and recreation. However, coastal water bodies such as Barnegat Bay are subject to impacts from coastal storm systems such as hurricanes and tropical storms. My assessment determined how physical water properties and chemistry including water temperature, dissolved oxygen, pH, salinity, turbidity, specific conductance, and chlorophyll A were affected during landfall of Hurricane Sandy on October 29, 2012. Data on these properties was collected from available sources and were analyzed for significance in year-long data before and after hurricane landfall as well as one week before and after landfall in 2012 as compared with 2013. Results suggest that significant changes in water temperature, dissolved oxygen, pH, turbidity and chlorophyll a were observed in the week before compared with after the hurricane, while only significant changes in pH, turbidity and chlorophyll a could be observed in the year-long analysis. These data could be used to encourage further research in impacts to bay systems from coastal storms and to help create restoration plans following a storm system or preventive measures to ensure the health of the bay after major storms.
Evaluating growth-defense trade-offs in ponderosa pine (Pinus ponderosa) in response to stimulated bark beetle attack
(Montana State University - Bozeman, College of Agriculture, 2019) Hull-Jones, Jessica Wrae; Chairperson, Graduate Committee: Amy Trowbridge
The mountain pine beetle (MPB; Dentroctonus ponderosae, Hopkins, Coleoptera: Curculionidae: Scolytinae) and its associated blue stain fungi are considered to be among the greatest natural threat to conifer ecosystems worldwide. In response to a rapidly changing climate, namely more frequent and hotter droughts, bark beetles benefit through a combination of higher reproductive capacity and greater availability of weakened and stressed host trees. Conifers have potent constitutive and induced chemical defenses to resist the bark beetle-fungi complex, but investment in these carbon-based defenses may be constrained by trade-offs associated with a tree's inherent growth rate. Although there are trade-offs that exist among all processes, it is unclear whether those particular growth-defense trade-offs are measurable and can be compared between individuals within various populations. Here we assess the concentration and composition of constitutive and induced terpene chemical defenses as a function of intraspecific variation in growth rates (slow-versus fast-growing mature ponderosa pines). We examine these relationships in the context of classical plant defense theories as well as the current state of the field. By determining the variation in chemical responses to stimulated bark beetle attack we can further our understanding of potential resistance trade-offs that might exist in stands that are being selectively bred for fast growth.