Life Sciences Commons^™

Ecology And Population Dynamics Of Salmonids In The Columbia River: Response Of Fishes To Anthropogenic Change In A Large Riverscape, Timothy Sean Elder

Dissertations and Theses

Freshwater ecosystems and the species that reside therein are disproportionately imperiled compared to terrestrial systems. Over the past 150 years, the Columbia River basin in the western United States has gone from one of the most productive and abundant salmon watersheds in the world, to having just a small fraction of its former salmon abundance. The cause of declines in salmon productivity and abundance are related to overlapping and confounding stressors including changes in large-scale climatic patterns and anthropogenic alterations within and adjacent to the Columbia River. Four main anthropogenic stressors have been identified as the leading causes of salmonid …

Mooring Impacts On Zostera Marina Meadows And Associated Epifauna In Nantucket Harbor, Massachusetts, Usa, Andrew Wright Mccandless

Dissertations and Theses

Seagrass ecosystems are some of the most productive in the world and provide a variety of ecosystem services but are facing global decline chiefly due to anthropogenic disturbance. Mechanical disturbances to seagrass meadows from anchoring, propeller scars, and mooring scars result in losses or damage to both shoots and the underlying rhizome. I conducted a literature synthesis on the extent of, recovery from, and ecological impacts of these mechanical disturbances to seagrass meadows. The literature suggests that anchoring damage tends to be worst in deeper water where larger vessels anchor and can cause large (>100m²) loss per …

Composition And Dispersal Dynamics Of Vegetation Communities In Urban Riparian Forests, Christa Von Behren

Dissertations and Theses

In urban riparian areas, vegetation composition may be affected by urban land use changes at both the stream reach and the watershed scale. Moreover, the mechanisms by which seeds disperse may be affected both by reduction in seed sources due to vegetation removal and by the urban stream syndrome that produces flashier hydrographs and incised channels. I hypothesized that vegetation communities with high cover of native and hydrophilic species would be found in watersheds with high forest cover, while more limited cover of these species would be found in highly developed watersheds. Additionally, to examine the dispersal mechanisms contributing to …

Food Waste Diversion Programming In Post-Secondary Education, Manar Arica Alattar

Dissertations and Theses

The urgent need for reform of USA and global food systems is evident in the pervasiveness of both food waste and food insecurity. Such an inefficient system strains the environmental, social, and economic systems on which it relies. Although policy and infrastructure changes are essential, consumers can play a significant role by decreasing their food waste, given that consumer waste represents 60% of the waste along the food cycle in developed countries. Incorporation of food literacy and food waste education in school curricula may provide a meaningful entry point for promoting food waste reduction skills.

This dissertation presents context on …

Assessing The Effects Of Climate Change And Fuel Treatments On Forest Dynamics And Wildfire In Dry Mixed-Conifer Forests Of The Inland West: Linking Landscape And Social Perspectives, Brooke Alyce Cassell

Dissertations and Theses

Over the past century in the western United States, warming has produced larger and more severe wildfires than previously recorded. General circulation models and their ensembles project continued increases in temperature and the proportion of precipitation falling as rain. Warmer and wetter conditions may change forest successional trajectories by modifying rates of vegetation establishment, competition, growth, reproduction, and mortality. Many questions remain regarding how these changes will occur across landscapes and how disturbances, such as wildfire, may interact with changes to climate and vegetation. Forest management is used to proactively modify forest structure and composition to improve fire resilience. Yet, …

Recovery Of Zooplankton Communities To Whole-Lake Disturbance, Brian Newton Mcgann

Dissertations and Theses

Community assembly following disturbance is a key process in determining the composition and function of the future community. However, replicated studies of community assembly at whole ecosystem scales are rare. Here is described a series of whole-lake experiments in which the recovery of zooplankton communities is tracked following an ecosystem-scale disturbance. Fourteen lakes in eastern Washington were chosen: seven lakes were treated with rotenone, while the remaining seven were reference. Each lake was monitored up to six months before and one to two years after the rotenone treatments. Zooplankton tows were taken monthly, at a shallow, intermediate, and deep site …