Ecology and Evolutionary Biology Commons^™

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 …

The Discovery Of A Novel Bacteria From A Large Co-Assembly Of Metagenomes, Matthew Finkelberg

Masters Theses

In the summer of 2022, a co-assembly of metagenome was created using the microbes found at Barres Woods in Harvard Forest. 14 samples were taken, and sample was split into the organic and mineral layer, which totals 28 Bulk MAGs. Within this Co-assembly, 4 different genomes were found which were designated with the phylum of FCPU426. Three of which were considered medium quality and one being assigned high quality. The novel phyla first appeared in NCBI and GTDB databases in June 2018. The name FCPU426 dates to 2010 and was named based on the 16s amplicon sequencing.

The novel phylum …

Climate Change Attitudes Of United States Family Forest Owners And Their Influence On Forest Management Practices, Logan Miller

Masters Theses

Understanding family forest owners’ (FFOs’) attitudes and behaviors towards climate change will allow for more sustainable forest management practices to be implemented, helping to combat climate change and its impacts. The goals for this research are (1) to begin measuring U.S. FFO attitudes toward climate change, (2) to determine what factors impact these attitudes, and (3) to determine how they influence the FFO’s management practices using the Responsible Environmental Behavior (REB) framework (Hines et al. 1987). Chapter 1 explores the different facets of my thesis project focusing on forests and forests’ ecosystem services, forest ownership in the United States, and …

Factors Affecting The Distribution Of Malayan Sun Bear In Htamanthi Wildlife Sanctuary, Northern Myanmar, Min Hein Htike

Masters Theses

To understand the modeling challenges and to examine the important factors considered in Malayan sun bear (Helarctos malayanus) distribution studies, we reviewed 33 peer-reviewed articles published from 2003-2023. These studies used 54 environmental or anthropogenic variable types to investigate the distribution, habitat preference, and home range composition of sun bears. Most variable types are human disturbance (n=4), climate (n=3), topography (n=1), vegetation (n=11), or other ecological factors (n=3). Nevertheless, a number of rarely used variables might also be useful to include in future evaluations (i.e., food abundance), and observational evidence suggests that predator occurrence could also be informative. …

Evaluation Of Acoustic Telemetry Array Performance And Fine- Scale And Broad-Scale Spatial Movement Patterns For Coral Reef Species In Culebra, Puerto Rico, Roxann Cormier

Masters Theses

Acoustic telemetry is an important tool when studying the spatial ecology of marine animals. First, it is important to identify the challenges of using this tool in shallow tropical marine environments before tracking marine animals. One significant issue that can influence the effectiveness of acoustic telemetry is the efficiency or detectability of acoustic signals by receivers. Understanding factors influencing detection efficiency of acoustic tags is especially important for fine-scale positioning systems (such as the VEMCO positioning system, VPS) that use detections in an overlapping receiver network to calculate geographic positions of tagged fish. I modelled the efficiency of an acoustic …

Chemosensory Receptors In Berghia Stephanieae: Bioinformatics And Localization, Kelsi L. Watkins

Masters Theses

Chemosensation is achieved through the binding of chemical signals to chemoreceptor proteins embedded in the membranes of sensory neurons. The molecular identity of these receptors, as well as the downstream processing of chemosensory signals, has been well studied in arthropods and vertebrates. However, very little is known about molluscan chemosensation. The identity of chemoreceptor proteins in the nudibranch mollusc Berghia stephanieae are unknown. Data from other protostome and molluscan studies suggest Berghia may use ionotropic receptors for some forms of chemoreception. This study used a bioinformatics approach to identify potential chemosensory ionotropic receptors in the transcriptome of Berghia. A …

Songbird-Mediated Insect Pest Control In Low Intensity New England Agriculture, Samuel J. Mayne

Masters Theses

Global agricultural intensification has caused large-scale wildlife declines, but agricultural lands that maintain natural habitats can support healthy wildlife populations and receive significant ecosystem services from these natural communities. However, how on-farm biodiversity results in beneficial ecosystem services is highly variable and is reported to differ among taxa and guilds. One group that has attracted attention for their potential beneficial role in reducing pest abundance are birds. Understanding the role of bird communities and individual species in pest control could be important for managing farms under a low intensity agroecological framework. In New England, farmers are increasingly applying low intensity …

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 …

Factors Influencing Primate Hair Microbiome Diversity, Catherine Kitrinos

Masters Theses

Primate hair is both a substrate upon which essential social interactions occur and an important host-pathogen interface. As commensal microbes provide important immune functions for their hosts, understanding the microbial diversity in primate hair could provide insight into primate immunity and disease transmission. While studies of human hair and skin microbiomes show differences in microbial communities across body regions, little is known about the nonhuman primate hair microbiome. In this study, we collected hair samples (n=159) from 8 body regions across 12 nonhuman primate species housed at 3 US institutions to examine 1) the diversity and composition of the primate …

Patterns And Mechanisms Of Intraspecific Trait Variation Across Thermal Gradients In A Marine Gastropod, Andrew R. Villeneuve

Masters Theses

As the earth’s climate changes due to anthropogenic emissions, it has increasingly become an imperative within the ecological community to understand existing species adaptations to climate change. Much focus has been paid to how a species might react to climate change, but the role of locally adapted traits and responsible environmental mechanisms have received less attention. Quantifying how sublethal (e.g. growth rates) and lethal (e.g. thermal tolerance) trait performance vary between populations can thus improve our understanding of how populations, and the entire species, will react to climate change. Here, I quantified the spatial patterns of performance of several traits …

Evaluation Of Environmental Factors Influencing American Marten Distribution And Density In New Hampshire, Donovan Drummey

Masters Theses

Though the American marten (Martes americana) is widely distributed across northern North America, habitat use and population abundance vary widely across the range. Due to its status as a furbearer, the species has been extensively researched, resulting in a large body of knowledge about the species’ ecology, distribution, and abundance, as well as drivers of population structure and dynamics. More recently, marten research has shifted focus to genetics, habitat associations, and estimation of population state variables. The rapid increase in estimation of states such as occupancy, abundance, and density has likely been driven by the increasing accessibility of …

Applying Ecological Theory To Amphibian Populations To Determine If Wood Frogs (Lithobates Sylvaticus) Are Ideal And Free When Selecting Breeding Habitat, Taylor M. Braunagel

Masters Theses

Amphibian populations are declining globally due to a litany of factors including pollution, disease, climate change, and most importantly, habitat destruction. As most amphibian life histories involve their populations being recruitment limited, focusing on the mechanism behind breeding habitat selection will reveal useful cues that managers may use to increase abundance and breeding success. Though there are many theoretical models that describe the distribution of animals in response to a resource, the ideal free distribution (IFD) theory has not yet been applied to amphibian settling decisions. Through this application of the IFD, I have found that a population of wood …

Trait Variation And Long-Term Population Dynamics Of The Invasive Alliaria Petiolata (Garlic Mustard) Across Three Microhabitats In Its Invaded Range, Laura Hancock

Masters Theses

Long-term population dynamics across heterogeneous environments can be a major factor in determining species’ ability to expand their ranges and persist in novel environments. Whether and how the relative performance of populations in different microsites over time impacts invasion into new microsites is poorly understood. Though largely restricted to disturbed semi-shaded microhabitats in its home range, the invasive herb Alliaria petiolata (garlic mustard) successfully invades intact forest understories – a novel microhabitat – in its introduced range, where it is known to impact above and below ground community composition. To test the hypothesis that source-sink metapopulation dynamics may be promoting …

Exploration Of The Association Between Muscle Volume And Bone Geometry Reveals Surprising Relationship At The Genetic Level, Prakrit Subba

Masters Theses

The evolution of jaws in cichlid fishes of the East African Great Lakes is a textbook example of adaptive radiation in vertebrates. Karl Liem postulated that this adaptive radiation has been possible due to the functional decoupling of two cichlid functional units – the pharyngeal jaw (PJ) and the oral jaw (OJ). This functional decoupling of the jaws has enabled the OJ to be relieved of its dual role of prey capturing and processing and has allowed the PJ to take on the role of prey processing. As a result, African cichlids have adapted the morphology of their functional units …

In-Vitro Propagation And Fish Assessments To Inform Restoration Of Dwarf Wedgemussel (Alasmidonta Heterodon), Jennifer Ryan

Masters Theses

The dwarf wedgemussel (Alasmidonta heterodon) is a federally endangered freshwater mussel that once ranged from New Brunswick to North Carolina, but now only exists in isolated populations throughout its diminished range. Laboratory propagation in conjunction with augmentation or reintroduction is considered a critical component of dwarf wedgemussel restoration. My thesis aimed to I) develop in-vitro propagation techniques including methods to minimize microbial contamination for two Alasmidonta species and II) compile and assess critical fish assemblage information at existing dwarf wedgemussel presence and absence locations to inform future restoration activities. For the first objective (Chapter 2) I assessed three …

Habitat Associations Of Priority Bird Species And Conservation Value On Small, Diversified Farms In New England, Isabel Brofsky

Masters Theses

In recent decades, New England agriculture has become increasingly characterized by small, diversified farming operations with values deeply rooted in community and conservation. In sharp contrast to large-scale, high-intensity agriculture currently typified by the majority of North American farms, New England farmers commonly prioritize ecologically beneficial production practices such as reduced chemical inputs, integrated pest management (IPM), low tillage, cover cropping and crop rotation, and retention of natural habitats like woody hedgerows and herbaceous strips. Public support and demand for local, sustainable food, evidenced by the success of CSA (Community Supported Agriculture) in the region, has helped to bolster this …

Autonomous Recording Units As An Alternative Method For Monitoring Songbirds, Lindsay Clough

Masters Theses

There is an increasing interest in the use of autonomous recording units as an alternative survey method to point count surveys conducted by human observers; however, questions remain about whether or not these recording units perform similarly to point count surveys and produce valid, comparable results. The use of individual listeners to transcribe the acoustic data collected by autonomous recording units is a common method for the analysis of recorded acoustic data, but potential variability among transcribers raises questions about the standardization of listening protocols to decrease inconsistencies in transcription results.

Autonomous recording units have been used to monitor birds …

The Ecological Value Of Spruce Plantations In Massachusetts, Calvin Ritter

Masters Theses

The establishment of monoculture plantations of exotic tree species is common practice for supplementing native timber stocks. Such plantations typically provide inferior habitat for wildlife compared to native forest, which may result in a net reduction in biodiversity. However, some studies report that plantations may increase net biodiversity at the landscape scale by introducing novel habitats or supplementing existing natural forests. Using point count surveys, I examined six mature Norway spruce (Picea abies) plantations in western Massachusetts in 2016 and 2017 to evaluate bird use of these habitats relative to native forest stands. Count data were analyzed using …

Improving Growth And Survival Of Cultured Yellow Lampmussel (Lampsilis Cariosa) For Restoring Populations, Virginia Martell

Masters Theses

In North America 72% of freshwater mussel species are endangered, threatened, or of special concern due to factors such as habitat loss and degradation, biological invasion, and land use change. Propagation of freshwater mussels has been considered a necessary conservation strategy for population restoration where threats have been mitigated but small population sizes limit population viability. Yellow lampmussel is a species of freshwater mussel that is endangered, threatened, or imperiled throughout its range; therefore, I evaluated laboratory techniques (probiotic supplements and secondary rearing designs) to improve culture of yellow lampmussel for population restoration. Several aquaculture facilities commonly use probiotics; thus, …

An Examination Of Tern Diet In A Changing Gulf Of Maine, Keenan Yakola

Masters Theses

The Gulf of Maine is a dynamic ecosystem with rapidly warming sea surface temperatures (SSTs), therefore it is vital to understand how species interactions vary over time and space. In chapter two, I quantify and compare dietary differences among four tern species, across seven islands in the region, over a 32-year period. Multivariate statistical analyses were employed to discern spatial and temporal differences in foraging ecology. Findings suggest there are significant differences between species and islands; however, only three prey species comprise the majority of chick diet for all terns and islands. The reliance on only a few prey items …

Patterns Of Morphological Plasticity In Metriaclima Zebra And Danio Rerio Suggest Differently Canalized Phenotypes Due To Form-Function Relationships, Dylan Jockel

Masters Theses

In order to ascertain the degree of compatibility in developmental restructuring and behavioral plasticity between two fish species frequently made subject of laboratory research (Metriaclima zebra & Danio rerio), alternative trophic niche exposure experiments utilizing novel three-prong feeding treatments were conducted to obtain morphometric data, which demonstrated both species do bear some degree of plasticity. The results are somewhat complicated by differences in locality of detectable restructuring, which may be due to disparity in the form-function relationship for each species’ lineage. Each is notable in the manner of respective species’ jaw protrusion, as it is driven by anterior …

Visual Attention In Jumping Spiders, Margaret Bruce

Masters Theses

The different ways that animals extract and analyze visual information from their environment is of interest to sensory ecologists. Jumping spiders, well-known for visually guided mating and hunting behavior, are an interesting model for the study of visual attention because they quickly and efficiently integrate information from eight eyes with a small brain. Stimuli in front of the spider are examined by two functionally and morphologically distinct pairs of forward-facing eyes. The principal eyes discern fine details and have small retinas and thus a small visual field. However, their position at the back of moveable tubes within the cephalothorax expands …

Performance Of Floristic Quality Assessment In Massachusetts Forested Wetlands, Carolyn Gorss

Masters Theses

In order to combat the loss of valuable wetland functions and services, federal, state and tribal governments must have the tools to accurately assess and monitor the condition of wetland ecosystems. One particular method of wetland assessment is Floristic Quality Assessment (FQA), which has been growing in popularity throughout the United States since its creation in the 1970s. FQA relies on vegetative indicators of human disturbance to assess the integrity of an ecosystem. FQA calculations are based on Coefficients of Conservatism (C-scores), professionally-assigned scores ranging from 0-10 that denote a local species' tolerance to anthropogenic disturbance. Despite increasing interest in …

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 …

Modelling Bird Migration With Motus Data And Bayesian State-Space Models, Justin Baldwin

Masters Theses

Bird migration is a poorly-known yet important phenomenon, as understanding movement patterns of birds can inform conservation strategies and public health policy for animal-borne diseases. Recent advances in wildlife tracking technology, in particular the Motus system, have allowed researchers to track even small flying birds and insects with radio transmitters that weigh fractions of a gram. This system relies on a community-based distributed sensor network that detects tagged animals as they move through the detection nodes on journeys that range from small local movements to intercontinental migrations. The quantity of data generated by the Motus system is unprecedented, is on …

Direct And Indirect Effects Of Climate On Bird Abundance Along Elevation Gradients In The Northern Appalachians, Timothy Duclos

Masters Theses

The stratification of bird species along elevational gradients is widely reported, with montane bird communities typically characterized by distinctive species occurring in relatively small and isolated populations; as such, these species are the subject of considerable interest to ecologists and conservationists. The stratification of species along elevation is largely attributed to compressed climatic zonation. Recent evidence that bird species are shifting up in elevation has fueled speculation that these species are tracking their climactic niches in response to climate change. However, there is also evidence plant communities are shifting in elevation, presenting a potential additional mechanism explaining changes observed in …

Botswana’S Elephant-Back Safari Industry – Stress-Response In Working African Elephants And Analysis Of Their Post-Release Movements, Tanya Lama

Masters Theses

Understanding how African elephants (Loxodonta africana) respond to human interactions in ecotourism operations is critical to safeguarding animal and human welfare and sustaining wildlife ecotourism activities. We investigated the stress response of elephants to a variety of tourist activities over a 15-month period at Abu Camp in northern Botswana. We compared fecal glucocorticoid metabolite (FGM) concentrations across three elephant groups, including: eight elephants in an elephant-tourism operation (Abu herd), three elephants previously reintroduced back into the wild from the Abu herd, and wild elephants. There were no differences in FGM concentrations between the three groups of elephants. The highest observed …

Evaluation Of The Recreational Catch-And-Release Fishery For Golden Dorado Salminus Brasiliensis In Salta, Argentina: Implications For Conservation And Management, Tyler Gagne

Masters Theses

Golden dorado (Salminus brasiliensis, Cuvier, 1816) is increasing in popularity as a target for recreational anglers practicing catch-and-release (C&R) in northern Argentina and bordering countries. However, to date no research has looked at the potential social and ecological implications of growth in this recreational fishery. The first manuscript of this thesis assessed the consequences of C&R on golden dorado captured by anglers on the Juramento River in Salta, Argentina. This evaluation examined physical injury, physiological stress, reflex impairment, and short term post-release behavior to develop a clear set of evidence-based best practices for C&R. In addition, the Juramento …

Ecological Consequences Of Lost Anadromous Forage Fish In Freshwater Ecosystems, Steven R. Mattocks

Masters Theses

Beginning in the early 1600s, dam construction in New England obstructed anadromous fish access to spawning grounds during migration. As a result, anadromous forage fish populations have declined, which has impacted freshwater, marine, and terrestrial ecosystems. To determine the impacts of dams on anadromous forage fish and freshwater ecosystems, I used historical and current data to estimate population changes in alewives (Alosa pseudoharengus) from 1600-1900. A significant reduction in spawning habitat occurred in New England as a result of 1,642 dams constructed between 1600 and 1900, resulting in 14.8% and 16.6% lake and stream habitat remaining by 1900, …