Ecology and Evolutionary Biology Commons^™

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 …

Don't Delay: The Effects Of Tide Gates And Road-Stream Crossing Culverts On River Herring (Alosa Spp.) Spawning Migrations, Derrick J. Alcott

Doctoral Dissertations

River herring (Alosa spp.) are anadromous fish that spawn in freshwater rivers and lakes in North America from Florida to Nova Scotia, CA. They have been listed as a species of conservation concern due to dramatic stock declines observed in the 1970’s. Stocks have failed to show significant signs of recovery despite over a decade of harvest restrictions throughout their range. Bycatch in commercial fisheries and reduced access to spawning habitat due to anthropogenic barriers to migration, such as dams and tide gates, have been identified as major causes of the decline in herring populations. Physical barriers to …

Improving Understanding Of Forest Communities And Biodiversity With Multi-Dimensional Landscape Gradients, Ben J. Padilla

Doctoral Dissertations

This dissertation was motivated by a desire to understand the effects of habitat degradation and urbanization on a single species in a single study system in western Massachusetts, the red-backed salamander (Plethodon cinereus), but along the way unexpected conceptual and methodological hurdles caused the work to grow into a multi-species, multi-region, and multi-scale endeavor. As I designed my dissertation research and began considering approaches to quantifying heterogeneity and human influence in my study landscape, I recognized inconsistencies in methods used to define and quantify landscape metrics, particularly in urban systems. To investigate further, I conducted a critical review …

Fear, Parental Behavior, And Community Structure In Residential Lands, Aaron M. Grade

Doctoral Dissertations

In an urbanizing world, residential lands present an opportunity for conservation of biodiversity right in our backyards. Informed conservation necessitates a mechanistic understanding of how development influences animal populations and communities. Birds nesting in residential lands are less productive in urban yards than rural yards. Urban yards also have higher densities of potential predators, but lower per capita predation, indicating that direct predation is not entirely responsible for lack of productivity. I suggest that fear effects, also known as non-lethal effects, could be a mechanism by which predators exert indirect influence on bird parental behavior and nestling condition in urban …

Interacting Effects Of Climate And Biotic Factors On Mesocarnivore Distribution And Snowshoe Hare Demography Along The Boreal-Temperate Ecotone, Alexej P. Siren

Doctoral Dissertations

The motivation of my dissertation research was to understand the influence of climate and biotic factors on range limits with a focus on winter-adapted species, including the Canada lynx (Lynx canadensis), American marten (Martes americana), and snowshoe hare (Lepus americanus). I investigated range dynamics along the boreal-temperate ecotone of the northeastern US. Through an integrative literature review, I developed a theoretical framework building from existing thinking on range limits and ecological theory. I used this theory for my second chapter to evaluate direct and indirect causes of carnivore range limits in the northeastern US, …

How Do Adult Songbirds Learn New Sounds? Using Neuromodulators To Probe The Function Of The Auditory Association Cortex, Matheus Macedo-Lima

Doctoral Dissertations

The ability to associate sounds and outcomes is vital in the life history of many species. Animals constantly assess the soundscape for cues associated with threats, competitors, allies, mates or prey, and experience is crucial for those associations. For vocal learning species such as humans and songbirds, learning sounds (i.e. perception and association learning) is also the first step in the process of vocal learning. Auditory learning is thought to depend on high-order cortical brain structures, where sounds and meaning are bound. In songbirds, the caudomedial nidopallium (NCM) is part of the auditory association cortex and is known to be …

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 …

Investigating The Effects Of Winter Drawdowns On The Ecological Character Of Littoral Zones In Massachusetts Lakes, Jason R. Carmignani

Doctoral Dissertations

Anthropogenic alteration of water levels in lakes is a major stressor to the ecological integrity of littoral zones, which provide critical heterogenous resources that support diverse biological communities. Annual winter drawdowns have been practiced in Massachusetts (MA) for several decades; however, few studies have estimated impacts to littoral zone habitat and biological communities, particularly at relatively mild magnitudes (i.e., m) and in lakes that co-occur with other anthropogenic pressures (e.g., lakeshore development) as seen in MA lakes. My dissertation reviewed the winter drawdown literature and collected empirical data in MA lakes to characterize winter drawdown hydrological regimes and estimate responses …

De-Coding The Impact Of Evolved Changes In Gene Expression And Cellular Phenotype On Primate Evolution, Trisha Zintel

Doctoral Dissertations

The goal of the dissertation work outlined here was to investigate the influence of proximal processes contributing to evolutionary differences in phenotypes among primate species. There are numerous previous comparative analyses of gene expression between primate brain regions. However, primate brain tissue samples are relatively rare, and my results have contributed to the pre-existing data on more well-studied primates (i.e. humans, chimpanzees, macaques, marmosets) as well as produced information on more rarely-studied primates (i.e. patas monkey, siamang, spider monkey). Additionally, the primary visual cortex has not previously been as extensively studied at the level of gene expression as other brain …

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, …

Neogene History Of The Kuroshio Current Extension And Planktic Foraminifera Evolutionary Implications, Adriane Lam

Doctoral Dissertations

There are outstanding questions as to how important currents are to dispersal, especially for the evolution of planktic foraminifera. During the Neogene Period there were significant increases in the diversity of planktic foraminifera that occurred during major tectonic gateway closures, episodes of warming and cooling, and reorganization and development of ocean gyres and currents. Relatedly, the behavior of some currents, namely western boundary currents, remains unknown through these times of global tectonic and climate events. This dissertation addresses outstanding questions related to how the Kuroshio Current Extension, the western boundary current of the northwest Pacific, responded to major tectonic and …