Digital Commons Network^™

Use Of Unoccupied Aerial Vehicle (Drones) Based Remote Sensing To Model Platform Topography And Identify Human-Made Earthen Barriers In Salt Marshes, Joshua J. Ward

Masters Theses

Elevation is a foundational driver of salt marsh morphology. Elevation governs inundation and hydrological patterns, vegetation distribution, and soil health. Anthropogenic impacts at grand scales (e.g., rising sea levels) and local scales (e.g., infrastructure) have altered the elevation of the salt marsh surface, changing the topography and morphology of these ecosystems. This study establishes and assesses means to document and analyze these impacts using Unoccupied Aerial Vehicle (UAV) based remote sensing to model platform topography. This thesis’s first and primary study presents and compares methods of producing high-resolution digital terrain models (DTMs) with UAV-based Digital Aerial Photogrammetry (DAP) and Light …

A Multi-Regional Assessment Of Eastern Whip-Poor-Will (Antrostomus Vociferus) Occupancy In Managed And Unmanaged Forests Using Autonomous Recording Units, Jeffery T. Larkin

Masters Theses

State and federal agencies spend considerable time and resources to enhance and create habitat for wildlife. Understanding how target and non-target species respond to these efforts can help direct the allocation of limited conservation resources. However, monitoring species response to habitat management comes with several logistical challenges that are exacerbated as the area of geographic focus increases. I used autonomous recording units (ARUs) to mitigate these challenges when assessing Eastern Whip-poor-will (Antrostomus vociferus) response to forest management. I deployed 1,265 ARUs across managed and unmanaged public and private forests from western North Carolina to southern Maine. I then …

Heat Flow In The Southern Margin Of Salar De Atacama: Deep Groundwater Temperature Distributions And The Implications For Subsurface Flow And Land Surface Energy Budgets, Graham Thomas

Masters Theses

Salar de Atacama (SdA) located in Northern Chile is home to one of the planet’s largest salar systems and lithium resources. Managing groundwater resources in salars is not obvious due to the lack of scientific understanding on the connectivity between the freshwater and brine systems. Using heat as a tracer in SdA provides a cost-effective method to further investigate groundwater flow in salars. This study employs 372 temperature-depth profiles from 90 boreholes between 2013-18 to understand the distinct thermal zones and flow between them in SdA. Three thermal zones exist within the southern margin of SdA’s thermal regime, at higher …

Microplastics In Local Communities’ Tap Water, Zachary T. Rattell

Masters Theses

Microplastics are an emerging environmental contaminant. One of the ways microplastics can get into the environment is by the breakdown of larger plastics. These plastics can come from industrial practices, discarded fabrics, agriculture, and general plastic waste. As these plastics are broken down microplastics leach into the environment. The widespread use of plastics has resulted in the spread of microplastic contaminants all over the world. Microplastics have been reported to be in drinking water, so this paper is looking at the presence of microplastics in local communities of different demographics and socioeconomic statuses. In other studies of different drinking water …

The Use Of Biological Soil Health Indicators To Quantify The Benefits Of Cover Crops, Alexander Wu

Masters Theses

Soils provide many essential functions that support the world. With a decline in soil health, these functions also decrease in efficiency, and can threaten the health of billions of people around the world. Typically, soil health tests do not use biological indicators, however microbes drive and perform vital functions to increase soil health. One way to increase soil health is through the use of cover crops to reduce soil erosion during fallow periods, increasing soil organic matter, as well as collecting nutrients from soil into their biomass. These cover crops are then terminated through various methods such as herbicides, disk …

Modeling Spatial Distributions Of Tidal Marsh Blue Carbon Using Morphometric Parameters From Lidar, Bonnie Turek

Masters Theses

Tidal marshes serve as important “blue carbon” ecosystems that accrete large amounts of carbon with limited area. While much attention has been paid to the spatial variability of sedimentation within salt marshes, less work has been done to characterize spatial variability in marsh carbon density. Driven by tidal inundation, surface topography, and sediment supply, soil properties in marshes vary spatially with several parameters, including marsh platform elevation and proximity to the marsh edge and tidal creek network. We used lidar to extract these morphometric parameters from tidal marshes to map soil organic carbon (SOC) at the meter scale. Fixed volume …

The Relative Effects Of Functional Diversity And Structural Complexity On Carbon Dynamics In Late-Successional, Northeastern Mixed Hardwood Forests, Samantha Myers

Masters Theses

Late-successional forests provide a unique opportunity to explore adaptive management approaches that mitigate atmospheric carbon dioxide levels through carbon storage while also enhancing ecological resilience to novel climate and disturbances. Typical benchmarks for adaptive forest management include species diversity and structural complexity, which are widely considered to increase ecosystem stability and productivity. However, the role of functional trait diversity (e.g., variation in leaf and stem traits) in driving forest productivity and ecosystem resilience remains underexplored. We leveraged existing continuous forest inventory (CFI) data and collected local functional trait observations from CFI plots within late-successional forests in western Massachusetts to explore …

Differential Toxicity Of Pm2.5 Components And Modified Health Effects Modeling: A Case Study In Nepal, Jeremy Brownholtz

Masters Theses

During the latter part of the 20^th century, a transition away from coal as a major energy source in developed countries was accompanied by a notable decrease in air pollution-related deaths in those countries. Currently the same phenomenon is being observed in developing nations like China and India. However, many areas that do still rely on coal for their energy production or industrial needs also reflect a gap in research on the effects of those specific processes on local populations. Located in Nepal at the foot of the Himalayan Plateau, Kathmandu represents one such location. The local economy of …

Identifying New Invasives In The Face Of Climate Change: A Focus On Sleeper Populations, Ayodelé C. O'Uhuru

Masters Theses

Sleeper populations are established populations of a non-native species whose population growth is limited by one or more abiotic or biotic conditions, such as climate change. While the northeastern US is predicted to be a hotspot for future invasions, identifying potential sleeper populations before they become invasive can inform proactive, climate-smart invasive species management. I focused on 169 introduced species that are established in one or more northeastern states. I used the Environmental Impact Classification for Alien Taxa (EICAT) framework to systematically identify and review the peer-reviewed literature for these candidate species to quantify their negative ecological and socioeconomic impacts. …

Dynamics Of Water Supply And Demand In The Bandama River Watershed Of Cote D'Ivoire, Sarah Alima Traore

Masters Theses

Water is a fundamental human right supporting life, health, and livelihoods. Yet water-related issues are ranked among the top five global economic risks (WEF, 2020). About two-thirds (4 billion) of the world's population live with severe water scarcity for at least one month, of which about 48% live in both India and China (Mekonnen et al., 2016). In Côte d'Ivoire, the Bandama River, one of the largest in the country, has struggled to meet expected demand, causing recurrent water and electricity shortages. The city of Bouaké in Côte d'Ivoire and neighboring towns experienced a severe water shortage in 2018 with …

Utilizing Climate Change Refugia For Climate Change Adaptation And Management In The Northeast, Sara A. Wisner

Masters Theses

To account for the effects of climate change, management plans in the northeast need to incorporate climate adaptation. Conserving climate change refugia is one adaptation strategy. Climate change refugia are areas buffered by climate change that enable the persistence of valued physical, ecological, and cultural resources; preserving these areas could be a potential adaptation strategy. Using a translational ecology approach where researchers and managers from the National Park Service, US Geological Survey, the University of Massachusetts, and elsewhere worked together, we focused on identifying refugia for tree, herbaceous plant, mammal, and bird species in order to prioritize them for conservation …

Assessment Of The Economic And Ecosystem Service Contributions Of Usda Forest Service Landowner Assistance Programs In The Conterminous United States, Jacqueline S. Dias

Masters Theses

Forests provide immense goods and services to both local and regional communities. The USDA Forest Service’s, State and Private Forestry program administer multiple landowner assistance programs aimed at helping private forest owners while supporting the continued supply of ecosystem services (e.g., timber harvesting, recreation, carbon sequestration and storage). The two landowner assistance programs assessed in this study are the Forest Legacy Program (FLP) and the Forest Stewardship Program (FSP). A majority of the nation’s forests are privately owned, many of which are facing deleterious impacts like wildfires, invasive species, development pressures, and other adverse effects from climate change. The goal …

Hydrologic Controls On Phosphorus Speciation And Mobilization In A Subalpine Watershed (East River, Colorado), Lucia Isobel Arthen-Long

Masters Theses

The cycling of phosphorus (P) through floodplain environments is critical to ecosystem productivity and has significant implications on both water quality and soil fertility. P export from soils in response to saturation has been well documented, but the relative vulnerability of specific P pools to mobilization remains poorly constrained, as do the mechanisms mediating its release. The prediction of P availability in and export from mountainous floodplain soils is of great importance as global climate change is projected to significantly alter precipitation regimes in alpine systems. This study combined a thorough characterization of P distribution across a hillslope to floodplain …

Statistical Improvements For Ecological Learning About Spatial Processes, Gaetan L. Dupont

Masters Theses

Ecological inquiry is rooted fundamentally in understanding population abundance, both to develop theory and improve conservation outcomes. Despite this importance, estimating abundance is difficult due to the imperfect detection of individuals in a sample population. Further, accounting for space can provide more biologically realistic inference, shifting the focus from abundance to density and encouraging the exploration of spatial processes. To address these challenges, Spatial Capture-Recapture (“SCR”) has emerged as the most prominent method for estimating density reliably. The SCR model is conceptually straightforward: it combines a spatial model of detection with a point process model of the spatial distribution of …

Algorithm Performance On The Estimation Of Cdom And Doc In The North Slopes Of Alaska, Monica Weisenbach

Masters Theses

Use of satellite imagery makes environmental monitoring easy and convenient with little of the logistics involved in planning sampling campaigns. Colored dissolved organic matter (CDOM) is an important component to track as a proxy for the large pool of dissolved organic carbon (DOC). In a world contending with the looming issue of global climate change, the ability to investigate the carbon cycle of inland to coastal environments allows for examination of the magnitude of carbon flowing through the system and potential changes over years. The Arctic region is a critical area for climate change impacts but is a difficult landscape …

Coastal Groundwater Catchments Of The Gulf Of Alaska, Aeon Russo

Masters Theses

High latitude mountain environments are experiencing disproportionately adverse effects in a currently changing climate. The Gulf of Alaska (GoA) region is an exemplar of this. Dramatic shifts are occurring in the region’s freshwater reservoirs as glaciers retreat more with each passing year. Research in the region places much focus on observing and predicting climate driven shifts in glacier mass balance, surface discharge, and associated nutrient fluxes to the ocean. On the other hand, coastal groundwater discharge (CGD) is given very little attention. Global and near-global estimates of CGD indicate variable results spanning an order of magnitude. Focusing on regionally specific …

Assessing The Impacts To Society Associated With The Use Of Alternative Ammunition For Hunting On National Wildlife Refuges, Christopher Cahill

Masters Theses

Attempts to eliminate lead ammunition use for hunting through regulatory approaches can be controversial and contentious, despite extensive scientific evidence of the detrimental effect of lead on wildlife species. In the United States, voluntary approaches to non-lead use that have used outreach and education in place of regulatory approaches have achieved sustained behavioral change in hunter ammunition choice. However, voluntary approaches to alternative ammunition use can be confronted with both practical and social barriers. In collaboration with U.S. Fish and Wildlife Service and U.S. Geological Survey Cooperative Research Units Program, this study assessed the practical and social barriers associated with …

The Role Of Vegetative Cover In Enhancing Resilience To Climate Change And Improving Public Health, Anastasia D. Ivanova

Masters Theses

Changing temperature and precipitation patterns are causing degraded soil, water, and air quality which is negatively affecting the safety and health of people, and the productivity of urban and rural communities. However, research shows that implementing urban forests and cover crops into urban and rural landscapes, respectively, can mitigate these effects by providing ecosystem services. As extreme precipitation and heat events continue to intensify, there is a need for comprehensively assessing these ecosystem services under changing climates and for this information to be easily accessible by communities for rapid land-use decision making. Therefore, I investigated the role of urban forests …

How Can Employers Contribute To Reducing Commuter-Generated Carbon Emissions? Evaluating Employer-Provided Commuter Benefits In Cambridge, Ma, Mary Richards

Masters Theses

Encouraging a more sustainable commuter mode shift and improving urban transportation systems have the potential to reduce anthropogenic greenhouse gas emissions (GHGs), a major contributor to climate change. Replacing some single-occupancy vehicle (SOV) trips with alternative modes of transportation, such as public transit, walking, or bicycling, represents one approach to begin reducing transportation-related emissions. Collectively, these shifts in transportation patterns would help to reduce the negative social, economic, and environmental costs associated with high rates of personal vehicle use. Employer-provided benefits programs have the potential to influence commuter behavior by making sustainable, alternative commuting choices a more convenient and economically …

Does Invasion Science Encompass The Invaded Range? A Comparison Of The Geographies Of Invasion Science Versus Management In The U.S., Lara Munro

Masters Theses

Biases in invasion science lead to a taxonomic focus on plants, particularly a subset of well-studied plants, and a geographic focus on invasions in Europe and North America. Geographic biases could also cause some branches of invasion science to focus on a subset of environmental conditions in the invaded range, potentially leading to an incomplete understanding of the ecology and management of plant invasions. While broader, country-level geographic biases are well known, it is unclear whether these biases extend to a finer scale and thus affect research within the invaded range. This study assessed whether research sites for ten well-studied …

Enforcing Higher Standards For Flood Hazard Mitigation In Vermont, Tamsin Flanders

Masters Theses

The state of Vermont faces increasing risk of costly damage from catastrophic flooding events as climate change increases the frequency of heavy rains and cumulative precipitation. In addition to increasing flood inundation risk, extreme precipitation events are leading to high rates damage from fluvial erosion—erosion caused by the force of floodwater and the materials it carries. As in all U.S. states, flood hazard governance in Vermont is shared by multiple levels of government and involves a complex compliance model that relies on local governments to regulate private property owners to achieve community, state, or federal goals.

To encourage municipalities to …

New England’S Underutilized Seafood Species: Defining And Exploring Marketplace Potential In A Changing Climate, Amanda Davis

Masters Theses

New England’s seafood industry has been searching for opportunities to diversify their landings and build resilience as it faces socio-economic challenges from a changing climate. Developing markets for underutilized species is one way the New England community could help their seafood industry build resilience. This thesis identified New England’s underutilized fish species and explored their marketplace potential by examining their availability in a changing climate, current availability to consumers, and consumers’ responses. In Chapter I, I account how New England’s seafood preferences have changed over time. In Chapter II, I identify New England’s seven underutilized seafood species: 1) Acadian redfish …

Arboriculture Safety Around The World, Jamie Lim

Masters Theses

Arboricultural work is inherently dangerous, with more serious injuries and fatalities than most other professions. Safety standards exist in some jurisdictions, but it is unclear how many standards exist, how they compare to one another, and whether (and how many) jurisdictions share standards. To establish a baseline understanding of these issues, my objectives were to (i) develop a database of existing standards, (ii) identify the most frequently occurring safety topics and (iii) describe similarities and differences in safety topics among standards from different countries. I worked with a variety of contacts and traditional university library resources to identify, obtain, analyze, …

Defining And Addressing Interconnected Goals In Groundwater Management Planning Across The Usa, Allison Gage

Masters Theses

Groundwater accounts for approximately 99% of the available freshwater on Earth, and is an important resource for irrigation, potable water, and domestic use in the United States. However, the overuse of groundwater has led to aquifer depletion in several basins across the USA, resulting in storage reduction, contamination, salt water intrusion, and depletion of surface waters. To properly manage groundwater for the future, there is a need for well-informed Groundwater Management Plans (GWMPs) in order to prevent further depletion and erosion of the resource. Previous studies have focused on groundwater management relative to groundwater laws, regulations, and institutional arrangements. This …

Hydrologic Structure And Function Of Vernal Pools In South Deerfield, Massachusetts, Charlotte Axthelm

Masters Theses

Vernal pools are small, ephemeral wetlands lacking an inlet or outlet. These wetlands, also known as seasonal pools, are found in a wide range of biomes, and their characteristics vary based on location. While the vegetation of western U.S. pools, and amphibians of eastern U.S. pools have been extensively studied, many aspects of vernal pools have not been fully characterized. In particular, although the general seasonal wetting and drying cycle is understood qualitatively, few studies have attempted to quantify the hydrological regime of vernal pools in New England. As water level variation drives many, if not all, of the characteristics …

Eastern Whip-Poor-Will Habitat Associations In Fort Drum, Ny, Kimberly Spiller

Masters Theses

The eastern whip-poor-will (Antrostomus vociferus: hereafter whip-poor-will) has been declining from historical population levels throughout its range in the northeast. Although whip-poor-wills have been reported to use a variety of habitats, most recent studies have associated whip-poor-wills with open habitat, such as early-successional habitats or forest edges. Population declines of other early-successional bird species have been attributed to the loss of early-successional disturbance-dependent habitats in the northeast, and it has been suggested that habitat loss is a significant factor in whip-poor-will population declines, as well. However, there remain substantial gaps in our understanding of whip-poor-will habitat associations, and …

Plants, Parasites, And Pollinators: The Effects Of Medicinal Pollens On A Common Gut Parasite In Bumble Bees, George Locascio

Masters Theses

Declines in several pollinator species are due to a variety of factors, including pathogens. Incorporating pollinator-friendly plant species into wild and agricultural habitats could reduce the stress of pathogens if food sources act medicinally against pathogens. Previous research demonstrated one domesticated sunflower cultivar (Helianthus annuus) can dramatically reduce a gut pathogen (Crithidia bombi) of the common eastern bumble bee, Bombus impatiens. To ascertain the breadth of this medicinal trait, we tested whether pollen from several H. annuus cultivars and four relatives could also reduce C. bombi infections in B. impatiens. We also investigated whether …

Watershed-Scale Modeling For Water Resource Sustainability In The Tuul River Basin Of Mongolia, Javzansuren Norvanchig

Masters Theses

Water scarcity is a prevalent issue all over the world. Growing water abstractions combined with uncertain effects of climate increase competition for scarce water resources worldwide, especially in arid and semiarid regions. It is crucial to assess and manage available water resources to ensure its sustainability. There is a need for integrated water management at a watershed scale. Watershed models are a useful tool to support sustainable water management and investigate effects of hydrologic responses at various scales under climate change conditions and to simulate effects of the management decisions. This study aims to assess the sustainability of water resources …

Mapping Sandbars In The Connecticut River Watershed Through Aerial Images For Floodplain Conservation, Bogumila Backiel

Masters Theses

Active geomorphic features of rivers like sandbars provide habitat for endangered and threatened riparian plant and animal species. However, human development has altered flow and sediment regimes, thus impairing formation of sandbars and islands. Large scale mapping of the fluvial geomorphology in river ecosystems like the Connecticut River is are necessary to understand the dynamics of these features and preserve habitat. Orthophotographs from 2012 from United States Department of Agriculture's Farm Service Agency (FSA), National Agriculture Imagery Program (NAIP) were used to develop a model in ArcGIS Pro to identify fluvial geomorphic features in the Connecticut River and 12 of …

Juvenile River Herring In Freshwater Lakes: Sampling Approaches For Evaluating Growth And Survival, Matthew T. Devine

Masters Theses

River herring, collectively alewives (Alosa pseudoharengus) and blueback herring (A. aestivalis), have experienced substantial population declines over the past five decades due in large part to overfishing, combined with other sources of mortality, and disrupted access to critical freshwater spawning habitats. Anadromous river herring populations are currently assessed by counting adults in rivers during upstream spawning migrations, but no field-based assessment methods exist for estimating juvenile densities in freshwater nursery habitats. Counts of 4-year-old migrating adults are variable and prevent understanding about how mortality acts on different life stages prior to returning to spawn (e.g., juveniles …