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Articles 1 - 8 of 8
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Don't Delay: The Effects Of Tide Gates And Road-Stream Crossing Culverts On River Herring (Alosa Spp.) Spawning Migrations, Derrick J. Alcott
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
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
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
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
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 …
Investigating The Effects Of Winter Drawdowns On The Ecological Character Of Littoral Zones In Massachusetts Lakes, Jason R. Carmignani
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
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 …
Neogene History Of The Kuroshio Current Extension And Planktic Foraminifera Evolutionary Implications, Adriane Lam
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 …