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Full-Text Articles in Life Sciences

Deep Benthic Coral Habitats Of Glacier Bay National Park And Preserve, Alaska, Elise C. Hartill Aug 2019

Deep Benthic Coral Habitats Of Glacier Bay National Park And Preserve, Alaska, Elise C. Hartill

Electronic Theses and Dissertations

Glacier Bay National Park and Preserve in Southeast Alaska is a system of fjords that presents an ideal natural laboratory to study terrestrial, aquatic and marine patterns of succession due to its unique and recent history of deglaciation. The patterns of deep benthic community assemblages in the fjords of Glacier Bay were investigated by quantitative assessment of underwater photo-quadrats collected using a remotely operated vehicle. The percent cover and diversity of species were lowest near the glaciated heads of the fjords and highest in the Central Channel and at the mouths of the fjords of Glacier Bay, where oceanographic conditions ...


Assessing The Mechanisms And Implications Of Altered Carbon Cycling In Arctic And Boreal Lakes, Rachel Fowler May 2019

Assessing The Mechanisms And Implications Of Altered Carbon Cycling In Arctic And Boreal Lakes, Rachel Fowler

Electronic Theses and Dissertations

Dissolved organic carbon (DOC) is an important component of lake ecology, as it contributes to light attenuation and carbon cycling. In recent years, DOC declined in a suite of lakes in Greenland. I performed experiments to test potential mechanisms of DOC loss. The tested mechanisms did not reduce DOC concentration, but DOC composition was affected. I also paired water quality data with meteorological observations to evaluate effects of climate drivers on lake variables. The lake variables were temporally coherent and associated with patterns of mean annual precipitation.

In the northeastern U.S., recovery from acidification and climate change have contributed ...


Living On The Edge: Thermophysiology Of The Southern Flying Squirrel At Its Northern Range Margin, Vanessa R. Hensley May 2019

Living On The Edge: Thermophysiology Of The Southern Flying Squirrel At Its Northern Range Margin, Vanessa R. Hensley

Electronic Theses and Dissertations

Climate change has the potential to upset entire ecological systems, making predictive models of the utmost importance. The incorporation of physiological parameters into predictive models not only bolsters their accuracy but also provides a mechanistic explanation for ecological changes already observed and those yet to come. North American flying squirrels, for example, have already experienced dramatic range shifts northward over recent decades, with climate change being the suspected driver. While other studies have focused on warming winter temperatures, I explored the hypothesis that rising summer temperatures were driving the observed range shifts. Unable to find a reliable population of the ...


Response Of Estuarine Fish Biomass To Restoration In The Penobscot River, Maine, Justin R. Stevens May 2019

Response Of Estuarine Fish Biomass To Restoration In The Penobscot River, Maine, Justin R. Stevens

Electronic Theses and Dissertations

Diadromous fish require both freshwater and marine habitat to complete their life cycle. Dams restrict the movement between these habitats and as a result, many populations are historically low across their range. The Penobscot River is the second largest river in Maine and once had large populations of diadromous fish and it has been the focus of mainstem dam removals, dam passage improvements, and stocking with the goal of restoring those populations. Since 2012, NOAA Fisheries has conducted surveys of the Penobscot Estuary using mobile, multi-frequency echosounders (SIMRAD EK60 split-beam 38 and 120 kHz) combined with mid-water trawl surveys to ...


Assessing Migrations And Habitat Connectivity For Two Anadromous Species Following A Major Restoration Effort In The Penobscot River, Maine, George A. Maynard May 2019

Assessing Migrations And Habitat Connectivity For Two Anadromous Species Following A Major Restoration Effort In The Penobscot River, Maine, George A. Maynard

Electronic Theses and Dissertations

The construction of industrial dams across major rivers in New England began in the early 1800s with textile mills in Massachusetts. Because of its legacy of mill dams and log driving dams, New England has the highest density of dams anywhere in North America, averaging one dam for every 44 km2 of drainage area. By the early 1900s, these dams drastically limited migrations by diadromous fishes, resulting in declines in populations of migratory fishes, including Atlantic salmon Salmo salar and American shad Alosa sapidissima. Since that time, different fishway designs and river management plans have been tried around the ...


Cascading Community Consequences Of Fish Adaptation, Zachary T. Wood May 2019

Cascading Community Consequences Of Fish Adaptation, Zachary T. Wood

Electronic Theses and Dissertations

Trophic interactions are an enduring framework for ecological thought. Broad and growing evidence for contemporary evolution has demonstrated that ecology and evolution dynamically interact on similar time scales. In this dissertation, I seek to understand how genetic and plastic trait change in human-influenced systems shape trophic dynamics, how such trait changes are constrained by inherent tradeoffs, and the broad implications of such trait change for ecological communities. I advance the premise that competition-defense tradeoffs are the essential mechanism behind many eco-evolutionary trophic dynamics that can reshape multi-trophic communities. In support of this view, I assess the presence of ecologically relevant ...


Ecological And Economic Implications Of Increased Storm Frequency And Severity For Boreal Lakes, Kathryn Warner May 2019

Ecological And Economic Implications Of Increased Storm Frequency And Severity For Boreal Lakes, Kathryn Warner

Electronic Theses and Dissertations

In boreal regions, increased precipitation events have been linked to increased concentrations of dissolved organic carbon (DOC), however less is known about the extent and implications of these events on lakes. We assessed the effects of precipitation events on six drinking water lakes in Maine, USA to better understand how DOC concentration and quality change in response to precipitation events. Our results revealed three types of responses: (1) an initial spike in DOC concentrations and quality metrics; (2) a sustained increase in DOC concentrations and quality metrics and; (3) no change during all sampling periods. Lake residence time was a ...


Improving Conservation Of Declining Young Forest Birds Through Adaptive Management, Anna Buckardt Thomas Apr 2019

Improving Conservation Of Declining Young Forest Birds Through Adaptive Management, Anna Buckardt Thomas

Electronic Theses and Dissertations

Early successional forest and shrubland habitats are collectively called young forest. Changes in disturbance regimes and land use conversion resulted in declines of young forest and associated wildlife across eastern North America. Conservation of declining young forest birds relies on the maintenance and creation of young forest habitats used for breeding. American Woodcock (AMWO; Scolopax minor) and Golden-winged Warbler (GWWA; Vermivora chrysoptera) are two declining young forest species. Conservation plans for both species use an adaptive management framework, which is an iterative process of planning, management actions, and monitoring and evaluation, in the context of species conservation goals. Adaptive management ...


Niche Evolution Along A Gradient Of Ecological Specialization, Meaghan Conway Apr 2019

Niche Evolution Along A Gradient Of Ecological Specialization, Meaghan Conway

Electronic Theses and Dissertations

The concept of the ecological niche is fundamental to understanding constraints on species distributions in space and time, and in explaining the origin and maintenance of biodiversity. A niche can be broadly defined to include all of the biotic and abiotic conditions that a species requires to persist. Niche breadth, or the degree of specialization, may influence how labile a species niche is, which can have broad implications for species ability to adapt to environmental change, and for explaining patterns of diversification. I investigated mechanism that facilitate or constrain niche evolution at multiple scales. First, I developed an index of ...


A Qualitative Study Of The Perceived Risks Of The Impacts Of Moose-Winter Tick Interactions On Human Health, Maine Economy, And Maine Culture, Asha Dimatteo-Lepape Apr 2019

A Qualitative Study Of The Perceived Risks Of The Impacts Of Moose-Winter Tick Interactions On Human Health, Maine Economy, And Maine Culture, Asha Dimatteo-Lepape

Honors College

In order to answer the question of how people perceive the interactions between winter ticks and moose, and the impacts that these interactions may have on culture, economy, and recreational practices in Maine, interviews were conducted with participants from four stakeholder groups: hunters, outfitters, Wabanaki citizens, and wildlife managers. By using a case study methodology, I was able to explore moose health risk perceptions as described by participants from the four stakeholder groups, and the likely impacts on recreation behavior, livelihoods and economic viability, cultural maintenance, and wildlife management. In this study, multiple data generation techniques (i.e., semi-structured interviews ...