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Full-Text Articles in Life Sciences

Ecology Of The Elusive: Genome-Informed Investigation Of Soil Microbial Diversity, Lauren Alteio Oct 2019

Ecology Of The Elusive: Genome-Informed Investigation Of Soil Microbial Diversity, Lauren Alteio

Doctoral Dissertations

Soil is considered one of the most diverse ecosystems on Earth, harboring diversity of organisms across the three domains of life. It is spatially and chemically heterogeneous: properties that intertwine in a complex matrix to support organismal diversity and function across different scales. Soil microorganisms both respond to and drive changes in ecosystems through metabolic activities. A single gram of soil is teeming with millions of cells comprised of thousands of species. Much of this diversity remains uncharacterized due to technical and methodological challenges faced by soil ecologists. Due to the complex physicochemical properties of soil and cross-feeding interactions between ...


Patterns Of Morphological Plasticity In Metriaclima Zebra And Danio Rerio Suggest Differently Canalized Phenotypes Due To Form-Function Relationships, Dylan Jockel Oct 2019

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 kinethmoid rotation in ...


Not Gone With The Wind: Addressing Effects Of Offshore Wind Development On Bat Species In The Northeastern United States, Zara Rae Dowling Nov 2018

Not Gone With The Wind: Addressing Effects Of Offshore Wind Development On Bat Species In The Northeastern United States, Zara Rae Dowling

Doctoral Dissertations

Development of coastal and offshore wind energy resources has the potential to add considerable renewable electricity capacity to the United States electrical grid, but could have detrimental impacts on wildlife. Land-based wind energy facilities are estimated to kill hundreds of thousands of bats every year in the United States, and could threaten population viability of some species. Little is known about the potential impacts of offshore wind development on bat populations along the North Atlantic coast, but a number of species are known to frequent marine islands or fly over the ocean during migration. This dissertation helps to characterize risks ...


Tracking Migratory Bird Movements In The Gulf Of Maine With Automated Radio Telemetry And Stable Hydrogen Isotope Markers, Jennifer Smetzer Mar 2018

Tracking Migratory Bird Movements In The Gulf Of Maine With Automated Radio Telemetry And Stable Hydrogen Isotope Markers, Jennifer Smetzer

Doctoral Dissertations

Coastal and offshore areas of the eastern United States provide valuable resources for both migratory songbirds and breeding seabirds, but face some of the most drastic rates of habitat alteration and urbanization. Coastal development can result in loss of significant habitats, and in proliferation of collision hazards that can pose a grave threat to birds. Conserving birds that use these coastal and offshore areas requires better information on how coastal stopover habitats are used, what breeding populations visit these regions during migration, how birds move through these landscapes, and how development can be most sensibly and responsibly directed to minimize ...


Direct And Indirect Effects Of Climate On Bird Abundance Along Elevation Gradients In The Northern Appalachians, Timothy Duclos Oct 2017

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 ...


The Effects Of Anthropogenic Stress On Nitrogen-Cycling Microbial Communities In Temperate And Tropical Soils, George S. Hamaoui Jr. Jul 2017

The Effects Of Anthropogenic Stress On Nitrogen-Cycling Microbial Communities In Temperate And Tropical Soils, George S. Hamaoui Jr.

Doctoral Dissertations

In this dissertation several research studies are discussed that characterize the effects of anthropogenic, or human-induced, stress on both ammonia-oxidizing and total bacterial soil microbial communities. The disturbances of land-use change in tropical, South American rainforests and artificial warming and nitrogen (N) fertilization in temperate, North American forests were investigated as these disturbances represent past and current disturbances caused by human landscape alteration and climate change. Initially, the response of soil ammonia-oxidizing microbial communities to land-use change from primary rainforest to pasture and, finally, back to secondary forest was determined. Next, these analyses of land-use change effects were expanded to ...


Methods For Incorporating Ecological Impacts With Climate Uncertainty To Support Robust Flood Management Decision-Making, Caitlin M. Spence Mar 2017

Methods For Incorporating Ecological Impacts With Climate Uncertainty To Support Robust Flood Management Decision-Making, Caitlin M. Spence

Doctoral Dissertations

Modern and historic flood risk management involves accommodating multiple sources of sources of uncertainty and potential impacts across a broad range of interrelated sectors. Sources of uncertainty that affect planning include internal climate variability, anthropogenic changes such as land use and system performance expectations, and more recently changes in climatology that affect the resources supporting the system. Flood management systems potentially impact human settlements within and beyond the systems’ scope of planning, local weather patterns, and associated ecological systems. Federal guidelines across nations have called for greater consideration of uncertainty and impacts of water resources planning projects, but methods for ...


Evaluating Resistance Surfaces For Modeling Wildlife Movement And Connectivity, Katherine Zeller Nov 2016

Evaluating Resistance Surfaces For Modeling Wildlife Movement And Connectivity, Katherine Zeller

Doctoral Dissertations

The continued growth of human populations and associated development in many areas of the world is causing persistent fragmentation of natural habitats. In response, wildlife corridors are often promoted as essential for the conservation of wildlife species. Wildlife corridors allow for the movement of individuals between habitat patches and confer many benefits including the maintenance of metapopulations and metapopulation dynamics, the maintenance of seasonal migratory routes, genetic exchange, and the potential for individuals and populations to shift their ranges in response to climate change.

Wildlife corridors are modeled across a resistance-to-movement surface where resistance represents the willingness of an organism ...


Ecological Consequences Of Lost Anadromous Forage Fish In Freshwater Ecosystems, Steven R. Mattocks Nov 2016

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 ...


Factors Affecting Habitat Quality For Wintering Wood Thrushes In A Coffee Growing Region In Honduras, Brett A. Bailey Nov 2016

Factors Affecting Habitat Quality For Wintering Wood Thrushes In A Coffee Growing Region In Honduras, Brett A. Bailey

Masters Theses

Amongst the diversity of taxa that occur in the Neotropics, 200 migratory bird species that breed in temperate North America can be found. Many of these populations have seen significant declines since the 1960s. The Wood Thrush, Hylocichla mustelina, is one such species. Shade coffee and other agroforestry practices show potential for benefiting migratory species, but the quality of coffee habitat and optimal habitat characteristics for Wood Thrushes remain unknown.

I surveyed a spatially complex, agricultural landscape in Honduras outside the recognized winter range of the Wood Thrush and radio-tagged 46 individuals within rustic coffee farms during the winters of ...


Modeling Historical And Future Range Of Variability Scenarios In The Yuba River Watershed, Tahoe National Forest, California, Maritza Mallek Jul 2016

Modeling Historical And Future Range Of Variability Scenarios In The Yuba River Watershed, Tahoe National Forest, California, Maritza Mallek

Masters Theses

In California's northern Sierra Nevada mountains, the fire-dependent processes of forest ecosystems have been interrupted and altered by human land use and fire suppression. U.S. Forest Service policy directs land managers to plan for a future that includes multiple use and the restoration of resilient ecosystems. Planning decisions are to be informed by an analysis of the range of variability of ecological processes at multiple scales. Current climate trends in the northern Sierra are of increasing temperatures, increased precipitation, and earlier snowmelt, as well as changes to the frequency and duration of drought. These climate changes have and ...


Variations In The Invertebrate Communities Of Wild Cape Cod Cranberry Bogs, Barbara Wagner Mar 2016

Variations In The Invertebrate Communities Of Wild Cape Cod Cranberry Bogs, Barbara Wagner

Masters Theses

As a species domesticated only in the last century, agricultural cranberry plants (Vaccinium macrocarpon) remain little removed from their wild relatives. Thus, it is a potential model species for studies of the earliest stages of domestication; however, there is little available quantitative information on its wild population biology and ecology. As such information is vital to studies of the ecological changes occurring during domestication, the purpose of this study was to consolidate the relevant knowledge available and conduct a preliminary search for patterns in the invertebrate communities of wild bogs. The alpha diversity was found to be greater than the ...


The Effectiveness And Applicability Of Amphibians As Indicator Species For Long-Term Monitoring Of Ecological Changes In New England Forests, Ahmed Siddig Aug 2015

The Effectiveness And Applicability Of Amphibians As Indicator Species For Long-Term Monitoring Of Ecological Changes In New England Forests, Ahmed Siddig

Doctoral Dissertations

The objective of this study is to assess the potential of two amphibians species, Eastern Red-backed Salamander (Plethodon cinereus (Green)) and Eastern Red-spotted Newt (Notopthalmus viridescens viridescens Rafinesque), as indicator species of forest disturbances at Harvard Forest, located in Petersham, Massachusetts, United States. Specifically, I 1) assess the impacts of these focal species to decline of hemlock forests in Harvard Forest; 2) calibrate abundance indices of P. cinereus based on artificial and natural objects surveys with a population size estimator based on depletion sampling; and 3) assess the potential of these salamanders as indicator species by developing an objective and ...


Trends In Human-Wildlife Interactions As Related To Land Use And Human Density In Massachusetts, Michael A. Huguenin Jr Mar 2015

Trends In Human-Wildlife Interactions As Related To Land Use And Human Density In Massachusetts, Michael A. Huguenin Jr

Masters Theses

We conducted a study of human-wildlife interactions in Massachusetts, USA between April 2010 and May 2012. Our objectives were to (1) compile and summarize public-generated reports on human-wildlife interactions across Massachusetts; (2) evaluate reports based on species, public concerns, and seasonal distribution; and (3) evaluate public perceptions of human-wildlife interactions. We collected unsolicited reports of human-wildlife interaction submitted to the Massachusetts Division of Fisheries and Wildlife (MDFW) through phone calls, emails, and face-to-face communications from the public. We received 2,730 reports from 332 of 351 towns in Massachusetts regarding 76 different wildlife species ranging from moose (Alces alces) to ...


The Effect Of Thermoregulation And Roads On The Movements And Habitat Selection Of Moose In Massachusetts, David W. Wattles Mar 2015

The Effect Of Thermoregulation And Roads On The Movements And Habitat Selection Of Moose In Massachusetts, David W. Wattles

Doctoral Dissertations

Massachusetts, U.S.A. is located along the southern boundary of the geographic range of moose (Alces alces) in North America. This is an atypical environment for moose, because of its extremely high levels of human development and high year-round temperatures, which are possibly at the limits of moose physiological tolerances. I investigated the role of these two factors on moose movements and habitat selection to determine how human development of the landscape and temperature influence moose occupation of this extreme environment. In addition, the response of moose to these factors provides insights into the influence of development and temperature ...


Turning Up The Heat On The Little Things That Run The World: Evaluating The Impacts Of Climate Change On Ant Biodiversity In The Temperate Forest Communities Of The Northeastern United States, Israel Del Toro Nov 2014

Turning Up The Heat On The Little Things That Run The World: Evaluating The Impacts Of Climate Change On Ant Biodiversity In The Temperate Forest Communities Of The Northeastern United States, Israel Del Toro

Doctoral Dissertations

Climatic change threatens biodiversity worldwide. In the forests of the northeastern United States, climate change is expected to increase mean annual temperatures by up to 4.5˚C and change precipitation seasonality. These changes in climate are likely to have impacts on the biodiversity of the region. In order to better understand the impacts of climate change on biodiversity, I used ants, an indicator taxonomic group, to predict how ant communities and ant-mediated ecosystem processes change as the climate warms. In the first chapter of this dissertation, I review the major ecosystem processes and services mediated by ants using the ...


Vulnerability Of Logfin Inshore Squid (Loligo Pealeii) To Predation: The Influence Of Relative Prey Size And Behavior, Michelle Dana Staudinger Feb 2010

Vulnerability Of Logfin Inshore Squid (Loligo Pealeii) To Predation: The Influence Of Relative Prey Size And Behavior, Michelle Dana Staudinger

Open Access Dissertations

Cephalopods provide forage to a wide range of predators in marine food-webs. Despite their ecological importance, a basic understanding of the mechanisms controlling predation risk and demand is lacking. This is true of one of the most common species of squid found in the northwest Atlantic, the longfin inshore squid (Loligo pealeii). In this dissertation, I address this shortcoming by investigating the role that size and behavior play in influencing squid’s vulnerability to predation. I used long-term food habits, population survey, and commercial landings data, to quantify size-based patterns of predation respective to 25 species of predators. Additionally, I ...


Spatial Ecology, Population Structure, And Conservation Of The Wood Turtle, Glyptemys Insculpta, In Central New England, Michael T. Jones May 2009

Spatial Ecology, Population Structure, And Conservation Of The Wood Turtle, Glyptemys Insculpta, In Central New England, Michael T. Jones

Open Access Dissertations

Abstract (Summary) Wood turtles ( Glyptemys insculpta ) are of conservation interest rangewide. Anecdotal accounts demonstrate that some populations have been decimated since 1850, and recent studies demonstrate that declines are still underway. From 2004-2008 I investigated the ecology of wood turtles in Massachusetts and New Hampshire. I obtained between one and five years of annual home range data for 150 turtles, and evaluated population structure at 31 sites in five major watersheds. Seasonal floods displaced 7% of wood turtles annually in one watershed, and accounted for elevated mortality. Twelve wood turtles were displaced < 16.8 km, and two were displaced over a 65-foot dam. Several turtles overwintered at their displacement site and two returned successfully, indicating that floods are a mechanism of population connectivity. Several homing turtles ended up in new areas. Turtles occupied stream segments with gradient < 1%, lower than generally available. Agricultural machinery accounted for most observed mortality, followed by automobiles and mammals. Female turtles exhibit smaller home ranges in agricultural areas. Older turtles move farther from the river than do young turtles, possibly reflecting their familiarity with a former landscape. Population density ranged from 0-40.4 turtles/river-kilometer. The highest densities occur in central New Hampshire and lower densities occur in the Housatonic watershed. Population density is negatively correlated with agriculture at both riparian and watershed scales, and responds unimodally to forest cover. Wood turtle populations in western Massachusetts are declining by 6.6-11.2% annually. I estimated ages of turtles by assessing shell-wear rates from photographs. Wood turtles regularly achieve ages over 80 years, and like related species, do not exhibit clear signs of senescence. Old wood turtles are reproductively dominant, and their survival rates are twice as high as young turtles. Carapace scutes appear to require 80 years to become worn. Population modeling indicates that wood turtle populations are declining in New England due to anthropogenic and natural factors. Conservation efforts must address the effects of agriculture on adult survival. Climate change may negatively affect northeastern wood turtles through increased flooding. Populations in mountainous areas may be likely candidates for conservation because they don't occupy prime agricultural land, but may be more susceptible to floods.