Ecology and Evolutionary Biology 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 …

Determining The Physiological And Behavioral Responses To Elevated Salinity In The Freshwater Bivalves, Corbicula Fluminea And Lampsilis Ovata, John W. Roden

Electronic Theses and Dissertations

Salinization has been identified as an increasing threat to freshwater mussel diversity in recent years. Native mussels have been observed to display reduced salinity tolerance in comparison to some invasive bivalve species, but methods by which organismal tolerance is achieved are not well understood. This study was designed to compare the behavioral and physiological responses of the native Lampsilis ovata to that of the invasive Corbicula fluminea. Lampsilis were found to exhibit strong behavioral avoidance to salinity exposure, whereas Corbicula displayed very weak avoidance to comparable salinity concentrations followed by indications of osmotic conformation through physiological mechanisms. Prolonged valve …

The Occurrence Of Microplastics Among Freshwater Fish Guilds In A South Carolina Reservoir, Chasity Rae Moore

Graduate Theses

No abstract provided.

Impact Of Disturbance Regimes On Community And Landscape Biodiversity In Atlantic Coastal Pine Barren Ecoregion Streams, Sean T. Mccanty

Graduate Doctoral Dissertations

Streams are dynamic systems shaped by geographic location, hydrology, riparian vegetation, and in-stream habitat. Furthermore, ecosystem disturbance plays a major role in structuring stream communities and ecosystem processes. Disturbances include natural occurrences, such as flooding, drought, and fire events and anthropogenic disturbances such as land use changes, damming, and pollution. Agricultural use acts as a press disturbance regime, homogenizing the surrounding landscape and simplifying in-stream habitat, leaving legacy effects after farming ceases. Active restoration is intended to ameliorate these effects by reintroducing variation, with the goal of shifting the ecosystem into a more diverse and natural state. The act of …

Effects Of Light, Nutrients, And Salts On Microbial Biofilm Productivity And Detrital Processing In Aquatic Mesocosms, Bethanie Brooke Howard-Parker

Graduate Theses and Dissertations

Anthropogenic activities associated with urbanization, agriculture, and resource extraction continue to increase to support increasing needs of the growing population. These activities increase the amounts of pollutants entering freshwater streams and put aquatic ecosystems at structural and functional risk. Aquatic microbes play an important role in detrital processing in streams as a key linkage in moving carbon from detrital stocks into aquatic food webs. My research investigates the effects of light, nutrients, and salts on detrital microbes and decomposition in freshwaters using a mesocosm approach. In chapter one, I modified a current priming effect (PE) hypothesis model to include light …

Ecological Response To Altered Rainfall Differs Across The Neotropics, Diane S. Srivastava, Régis Céréghino, M. Kurtis Trzcinski, A. Andrew M. Macdonald, Nicholas A. C. Marino, Dimaris Acosta Mercado, Céline Leroy, Bruno Corbara, Gustavo Q. Romero, Vinicius F. Farjalla, Ignacio M. Barberis, Olivier Dézerald, Edd Hammill, Trisha B. Atwood, Gustavo C. O. Piccoli, Et Al.

Ecology Center Publications

There is growing recognition that ecosystems may be more impacted by infrequent extreme climatic events than by changes in mean climatic conditions. This has led to calls for experiments that explore the sensitivity of ecosystems over broad ranges of climatic parameter space. However, because such response surface experiments have so far been limited in geographic and biological scope, it is not clear if differences between studies reflect geographic location or the ecosystem component considered. In this study, we manipulated rainfall entering tank bromeliads in seven sites across the Neotropics, and characterized the response of the aquatic ecosystem in terms of …

Organic Matter Is A Mixture Of Terrestrial, Autochthonous, And Wastewater Effluent In An Urban River, Julia E. Kelso, Michelle A. Baker

Ecology Center Publications

Terrestrially derived organic matter (OM) is known to dominate the OM pool in reference watersheds. Urban watersheds are known to receive large OM loads compared to reference watersheds, but the proportion of terrestrial, autochthonous, and anthropogenic (e.g., wastewater effluent) sources of OM in urban watersheds remains unknown. Organic matter was identified as a pollutant of concern in the Jordan River, an urban river in the Salt Lake Basin, U.S.A. Our objective was to identify autochthonous, terrestrial, and anthropogenic sources of three size-classes of OM to the Jordan River to inform OM reduction strategies within the watershed. Samples of coarse particulate …

Land Use Influences Along Elevation Gradient On Macroinvertebrate Communities, Brittany Sprout

Electronic Theses and Dissertations

Land use activities have caused disturbances that affect the quality of freshwater ecosystems worldwide. How the influences of land use along an environmental gradient and the associated environmental variables that may influence stream diversity and function is unclear. We address these issues by studying biodiversity, abundance, and functional diversity of macroinvertebrates across different land types along a gradient in Colorado, USA. We also address how diversity may change along an elevation gradient by analyzing previously published macroinvertebrate research. We found evidence that land use and disturbance are stronger explanations of changes in macroinvertebrate communities, rather than elevation. Functional trait patterns …