Behavior and Ethology Commons^™

Responses Of Juvenile Atlantic Salmon To Competition And Environmental Change: Implications For Performance In Maine Streams, Nicole C. Ramberg-Pihl

Electronic Theses and Dissertations

New England’s climate is changing faster than that of any other region in the continental United States. Over the last century, Maine has experienced an increase in annual temperature of approximately 1.48^oC along with a 15 percent increase in annual precipitation. Temperature and precipitation play vital roles in shaping the ecology of freshwater environments. Therefore, changes in regional climate could undermine the structure and stability of Maine’s freshwater systems as they currently exist.

Maine currently harbors the last wild populations of Atlantic salmon (Salmo salar) in the United States. Atlantic salmon were once abundant in Maine …

Breeding Ecology And Habitat Use Of Unisexual Salamanders And Their Sperm-Hosts, Blue-Spotted Salamanders (Ambystoma Laterale), Kristine Hoffmann

Electronic Theses and Dissertations

Unsexual Salamanders within the Blue-Spotted Salamander Complex carry combinations of ambystomatid genomes (those of Blue-Spotted Salamanders, Ambystoma laterale, and Jefferson Salamanders, A. jeffersonianum in Maine). They are nearly all female, breed in wetlands, and use sperm of related species to reproduce. Little is known about their ecology to guide the conservation of this unique lineage. I examined breeding site occupancy, demographics, orientation, and terrestrial habitat selection of Unisexual Salamanders in comparison to Blue-Spotted Salamanders and other amphibians. I compared statistical tests of orientation to determine which was most appropriate for pitfall data.

Unisexual Salamander occupancy at breeding sites was positively …

Sources Of Ecologically Important Trait Variation In Mosquitofish (Gambusia Affinis And Gambusia Holbrooki), Heather Ann Arnett

Electronic Theses and Dissertations

The study of contemporary evolution and eco-evolutionary dynamics is classically defined in terms of genetic evolution, but the actual suite of processes driving contemporary trait change is likely much more complex than often credited. This dissertation considers additional mechanisms of trait change that might be important to an emerging model system for study of contemporary evolution and eco-evolutionary dynamics. Specifically, the research focuses on phenotypically plastic and demographic trait variation in Eastern and Western Mosquitofish (Gambusia affinis and G. holbrooki) facing the major ecological gradient of predation risk. Plasticity experiments employed a common-garden rearing design to manipulate fish …