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Natural Selection And Its Interactions With Migration And Population Demography: Experiments In Wild Guppy Populations, Dylan Jones Weese
Natural Selection And Its Interactions With Migration And Population Demography: Experiments In Wild Guppy Populations, Dylan Jones Weese
Electronic Theses and Dissertations
In this dissertation I quantify spatial and temporal variation in the pattern and strength of natural selection in wild populations of Trinidadian guppies (Poecilia reticulata), and assess the demographic costs of ongoing contemporary evolution in the form of selection against migrants. First, I describe the results often mark-recapture experiments to test hypotheses concerning the role of natural selection in geographic patterns of trait variation. Previous work has reported that guppies inhabiting high- and low-predation sites differ in both body shape and color. These patterns of phenotypic variation have been theorized to reflect differences in the balance between functional trade-offs among …
Analysis Of Optical Spikes Reveals Dynamics Of Aggregates In The Twilight Zone, Nathan Briggs
Analysis Of Optical Spikes Reveals Dynamics Of Aggregates In The Twilight Zone, Nathan Briggs
Electronic Theses and Dissertations
The "biological pump," whereby phytoplankton grow in the surface ocean, aggregate, and sink, is a critical process contributing to global atmospheric CO2 drawdown and provides the vast majority of food for deep ocean and benthic ecosystems. The strength of this pump hinges on the amount of material that stick together to form larger aggregates, the sinking rates of these aggregates, and the rate at which they are consumed as they sink. However, marine aggregates, also called "marine snow," are often fragile and notoriously difficult to sample, their sinking rates are highly variable and difficult to quantify, and their concentrations can …
Land Use Planning And Vernal Pool Conservation In A Southern Maine Town, Robert Carlton Freeman
Land Use Planning And Vernal Pool Conservation In A Southern Maine Town, Robert Carlton Freeman
Electronic Theses and Dissertations
In this dissertation I investigate the impacts of both growth management regulations and vernal pool protection regulations on landscape permeability for wood frogs (Rana sylvatica), a vernal pool-obligate species. Motivated by new legislation in Maine (USA) to protect vernal pools and the species that depend on them, I combined a spatially-explicit economic model of the conversion of undeveloped parcels to residential use with a landscape permeability model for wood frogs. I estimated the economic model using a Bayesian Gibbs Sampler to account for spatial error dependence and used the results to predict future landscape patterns in a focal town, Falmouth, …
Assessing The Biological Condition Of Maine Streams And Rivers Using Benthic Algal Communities, Thomas John Danielson
Assessing The Biological Condition Of Maine Streams And Rivers Using Benthic Algal Communities, Thomas John Danielson
Electronic Theses and Dissertations
The purpose of this study was to test and develop algal methods of evaluating the condition of Maine streams and rivers. The primary objective was to develop a statistical model to predict attainment of Maine's aquatic life criteria for water quality classes A, B, and C. I collected 298 samples of algae on rocks from 193 locations across the state. The major pattern in species composition related to conversion of forests to urban, residential, and agricultural land uses. I calculated preferred environmental conditions of 236 algal taxa for 1) concentrations of nitrogen, phosphorus, and dissolved ions in the water, 2) …