<p> The United States Fish and Wildlife service declared an unusual mortality event (UME) in 2006 when a high number of northern sea otters in Alaska were found dead beginning in 2002. Necropsies revealed the cause of death in 30% of cases to be septicemia with meningoencephalitis and/or vegetative valvular endocarditis (VVE) colonized by gram positive cocci, later determined to be primarily <i>Streptococcus infantarius</i> ss <i>coli</i> and <i>Streptococcus phocae</i>. While much work has been done to uncover the pathogenic agents responsible for these deaths in northern sea otters, the ecology of <i>S. infantarius</i> ss <i>coli</i> and <i>S. phocae</i> in the environment remains poorly understood. This study investigated the presence of <i>S. infantarius</i> ss <i> coli</i> and <i>S. phocae</i> in the marine environment by 1) developing a molecular method to detect <i>S. infantarius</i> ss <i>coli</i> 2) examining potential microbe-habitat associations in Kachemak Bay and Resurrection Bay, Alaska, and 3) determining the competency of otter prey species to act as reservoirs for these pathogens. A PCR assay was developed to detect the <i>sodA</i> gene of <i> S. infantarius</i> ss <i>coli</i> in both environmental and clinical samples. Water and bay mussels were collected from sites in Kachemak and Resurrection Bays and pathogen presence was determined using PCR. Habitat attributes were recorded onsite and determined using ShoreZone. Prey competency was determined via a dosing experiment in the lab. Our primer set for the <i> S. infantarius</i> ss <i>coli</i> <i>sodA</i> gene, as well as a previously published primer set for the <i>S. phocae</i> <i> sodA</i> gene, successfully identified our targets in clinical and environmental samples using conventional PCR. Primer sets we designed successfully quantified the <i>sodA</i> gene of <i>S. infantarius</i> ss <i> coli</i> and/or <i>S. phocae</i> in environmental samples and in dosed prey samples using qPCR. <i>S. infantarius</i> ss <i> coli</i> and/or <i>S. phocae</i> were present in water or mussels at 61 of 162 sites. Statistical analyses to determine bacterial correlations with habitat attributes revealed some correlations between habitat parameters selected and presence of our target bacteria in the environment. Prey competency experiments showed that bivalves were the most competent pathogen reservoirs. Results of this study will inform microbial ecologists and wildlife managers of the potential environmental risk factors for <i>S. infantarius</i> ss <i>coli</i> and <i>S. phocae</i> infection as well as provide information about pathogenic bacterial presence in the marine environment. </p><p>

The Hudson River estuary (HRE) is a well monitored aquatic resource and much secondary data exist for this system. We developed two objectives based on accessible HRE aquatic data. The first objective was to determine if changes in HRE fish community over the time period (1974 to 2005) years are correlated to local and regional climate. We addressed this objective by employing a multivariate statistical approach. We confirmed that the HRE fish community structure has changed over the time period (1974 to 2005). These changes are correlated with local hydrology (freshwater flow and water temperature) and regional climate (Atlantic Multidecadal Oscillation or AMO and North Atlantic Oscillation or NAO). We found that abundances of striped bass larval stages are positively correlated with high freshwater flows and juvenile shad abundances are negatively correlated with the AMO or warmer sea surface temperatures (SST). This finding suggests that climate-related variability affects HRE juvenile shad abundances and current management strategies for this declining species should include the implications of climate change. The second objective was to examine whether factors such as sediment type, water characteristics and distance to nearest submerged aquatic vegetation (SAV) beds affect the occurrence or presence/absence of juvenile American shad (Alosa sapidissima) and juvenile striped bass ( Morone saxatilis) in the HRE during the fall. We addressed this objective by applying geostatistics and general linear mixed effects models. We found the probability of presence for both species were commonly driven by spatial dependence or river mile, Julian day and salinity. Our results include maps depicting probability of occurrence (or presence) for both species throughout the HRE. We found the highest predicted probabilities of juvenile American shad presence are found in the Upper HRE. Conversely, highest predicted probabilities of juvenile striped bass presence are found in the Lower HRE. Habitat partitioning between these two species is present during the fall in this system but the mechanism is unclear. Future studies could address a possible predator-prey or competitive relationship between juvenile American shad and juvenile striped bass.

Anyone who has spent time in coastal New England has seen gulls flying overhead and heard their familiar sound; gulls may be one of the most recognizable birds in the world. There are over 50 species of gulls worldwide, and many of them are closely associated with human development or activities. In Massachusetts, there are several common gull species including herring (Larus argentatus), great black-back (Larus marinus), laughing (Leucophaeus atricilla), and ring-billed (Larus delawarensis). While coastal encounters with gulls are ubiquitous, gulls can also be found inland, and ring-billed and herring gulls are now a common sight at lakes, parks, and commercial parking lots dozens or hundreds of kilometers from the ocean. This inland population of gulls presents unique challenges and exciting research opportunities. Because they are often closely associated with human activity, concentrations of inland gulls can lead to potential water quality concerns (when large roosts form on public water supply reservoirs), airplane hazards (when groups of gulls concentrate near airports or flight paths), or disease transmission (when gulls forage at landfills or waste water treatment plants then visit areas with people). In the following chapters I explore various aspects of inland gull ecology during the non-breeding season. In chapter 1, I review the concept of philopatry in birds and discuss ways to assess site faithful behavior. In Chapters 2 and 3, I explore some of the ecological aspects of inland gulls. Chapter 2 examines the site fidelity of gulls to their wintering areas and my results suggest that gulls exhibit high winter-site fidelity but variable site persistence during the winter season. Chapter 3 explores roost site selection throughout the year and models roost selection in Massachusetts. My results indicate that ring-billed gulls prefer freshwater roosts, while herring gulls use saltwater roosts more often. In Massachusetts, both herring and ring-billed gulls select inland freshwater roosts based on the size of the water body and proximity to their last daytime location. In Chapter 4, I detail the results of an experimental study trying to reduce the amount of anthropogenic food available to gulls at inland parking lots. Ring-billed gulls were the most common gull found in parking lots, and my educational approach to reduce feedings had mixed results; education seemed to reduce the number of feedings in some cases, but the number of gulls in each parking lot was not affected. In Chapters 5 and 6, I detail some applied management techniques. Chapter 5 discusses efforts to exclude gulls from a waste water treatment plant in central Massachusetts. Overhead stainless-steel wires were completely effective at preventing gulls from using structures at the treatment plant. Chapter 6 describes an innovative technique that was used to efficiently and effectively catch gulls during winter in highly urbanized environments. I captured over 1000 gulls using a net launcher in various parking lots and other urban areas.

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abstract: Interdisciplinary research has highlighted how social-ecological dynamics drive the structure and function of the urban landscape across multiple scales. Land management decisions operate across various levels, from individuals in their backyard to local municipalities and broader political-economic forces. These decisions then scale up and down across the landscape to influence ecological functioning, such as the provisioning of biodiversity. Likewise, people are influenced by, and respond to, their environment. However, there is a lack of integrated research, especially research that considers the spatial and temporal complexities of social-ecological dynamics, to fully understand how people influence ecosystems or how the resulting landscape in turn influences human decision making, attitudes, and well-being. My dissertation connects these interdisciplinary themes to examine three questions linked by their investigation of the interactions between people and biodiversity: (1) How do the social and spatial patterns within an arid city affect people’s attitudes about their regional desert environment? (2) How are novel communities in cities assembled given the social-ecological dynamics that influence the processes that structure ecological communities? (3) How can we reposition bird species traits into a conservation framework that explains the complexity of the interactions between people and urban bird communities? I found that social-ecological dynamics between people, the environment, and biodiversity are tightly interwoven in urban ecosystems. The regional desert environment shapes people’s attitudes along spatial and social configurations, which holds implications for yard management decisions. Multi-scalar management decisions then influence biodiversity throughout cities, which shifts public perceptions of urban nature. Overall, my research acts as a bridge between social and ecological sciences to theoretically and empirically integrate research focused on biodiversity conservation in complex, social-ecological systems. My goal as a scholar is to understand the balance between social and ecological implications of landscape change to support human well-being and promote biodiversity conservation. / Dissertation/Thesis / Doctoral Dissertation Geography 2020

Includes bibliographical references / This thesis focuses on the economics and institutional aspects of community wildlife conservation in the context of local communities living adjacent to the Gonarezhou NationalPark in Zimbabwe. A significant proportion of wildlife in Zimbabwe, and in Southern Africa in general, is managed as a common pool resource by communities under community-based natural resource management. Several challenges threaten conservation efforts at both local and higher levels, thus hindering its ability to bring about development that might improve the welfare of poor rural communities participating in wildlife conservation. The most pressing issues in the wildlife sector include: inability to extract resource rents from wildlife conservation that in turn affect household welfare in terms of total household income and reduction in poverty and inequality, lack of capacity by local communities to solve collective action problems or lack of incentives to self-organise, and lack of comparable successful outcomes in CBNRM communities such as the wildlife conservancy communities. Learning from other successful communities that use community-based' models, such as wildlife conservancies, might provide important insights for policy makers and development practitioners. These issues are explored in three substantial papers included in this thesis. The thesis consists of five chapters starting with an introduction, followed by three papers and finally conclusions and policy implications. The study makes use of purpose-collected primary data from local communities living adjacent to Gonarezhou National Park in Zimbabwe. The first paper investigates the effects of wildlife resources on community welfare. Specifically, the paper examines the contribution of environmental income to) total household income,) poverty reduction, and) reduction in income inequality. Furthermore, it investigates the impact of environmental income on households in different income categories, the role of wildlife in the portfolio of environmental income and the determinants of environmental income generated by different households. To achieve the objectives above, the paper makes use of income quintile analysis, the Foster-Greer-Thorbecke poverty measure, Gini coefficient analysis, Ginidecomposition analysis, ordered logit regression model and instrumental variables estimation using heteroscedasticity-based instruments. The results show that the relative contribution of environmental income towards total household income is more pronounced in poor households, while the relative contribution of agricultural income is noticeable in wealthier households. In particular, wealthier households consumed more wildlife products in total than relatively poor households. However, poorer households derive greater benefit from the consumption of wildlife resources than wealthier households. Excluding wildlife compromised the relative contribution of environmental income and, at the same time, increased the relative contribution of farm and wage income. Environmental income has more impact in terms of poverty and inequality reduction in the lower income quintiles than in the upper quintiles. Wildlife income alone accounted for about 5.5% reduction in the proportion of households living below the poverty line. Furthermore, wildlife income had an equalizing effect, bringing about a 5.4% reduction in measured inequality.

Deep-sea organisms are increasingly subject to bycatch interactions worldwide. Recent studies have shown that discard mortality can lead to significant declines in deep sea fish stocks, and highlight the inherent vulnerability of deep sea organisms to overexploitation due to their shared suite of conservative life history characteristics. Estimating the post-release mortality (PRM) rates of these deep-sea organisms is a necessary step towards responsible fisheries management, particularly as PRM represents a substantial source of uncertainty when estimating total fishery mortality. The deep-sea giant isopod Bathynomus giganteus and its relatives are captured as bycatch in numerous fisheries, although knowledge is limited regarding their population trends or response to capture and release. In order to assess and predict PRM in B. giganteus, we used reflex action mortality predictors (RAMP) whereby the presence or absence of target reflexes was used to create a delayed mortality model, and considered factors affecting mortality. Mortality rates five days post-capture ranged from 50-100% and both RAMP scores and time at the surface were significant predictors of mortality, although our conclusions regarding the effect of surface time are limited. In-cage video documented little movement within the 24 h monitoring period following cage deployment, and it appeared that surviving individuals often fed within the holding period after cage deployment. Our results suggest that PRM in B. giganteus is common and that this unaccounted source of mortality should be quantified and investigated for other deep-sea crustaceans as well. Similarly, bycatch interactions with deep-sea elasmobranchs can lead to dramatic declines in abundance over short time scales. Sharks hooked in the deep sea could face a higher likelihood of severe physiological disturbance, at-vessel mortality, and PRM than their shallower counterparts. Unfortunately, robust PRM rates have not yet been estimated for deep-sea elasmobranchs and as such are not currently incorporated into total fishery mortality estimates or bycatch assessments, limiting the effectiveness of conservation or management initiatives. We empirically estimated PRM for two focal species of deep-sea shark, the Cuban dogfish Squalus cubensis and the gulper shark Centrophorus sp. using post-release cages deployed at-depth. We calculated 24 h PRM rates of 49.7% (± 8.5 SE) for S. cubensis and 83% (± 16 SE) for Centrophorus sp. and identified shark size (total length), blood lactate, blood pH, and vitality scores as predictors of PRM in Squalus cubensis. We also observed all PRM within 11 h post-capture and demonstrated the effects of capture and recovery depth on stress and behavior. Our results suggest that PRM rates of deep-sea sharks are higher than previously assumed, and highlight the need for filling in this gap in fishery mortality estimates for other common deep-sea discards in the future. / A Thesis submitted to the Department of Biological Science in partial fulfillment of the Master of Science. / Spring Semester 2016. / March 31, 2016. / bycatch, deep-sea, giant isopod, mortality, post-release, shark / Includes bibliographical references. / Brendan Suneel Talwar defended this Thesis on March 31, 2016, Professor Directing Thesis; Edward J. Brooks, Committee Member; Don Levitan, Committee Member; Joseph Travis, Committee Member.

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