Environmental Sciences Commons^™

Topographic Influences On Trends And Cycles In Nutrient Export From Forested Catchments On The Precambrian Shield, Samson G. Mengistu

Electronic Thesis and Dissertation Repository

This dissertation explored topographic controls on spatial and temporal patterns in water yield and nutrient (carbon, nitrogen and phosphorus) export from forested headwater catchments in the Turkey Lakes Watershed in central Ontario, where other factors contributing to differences in water yield and nutrient export, including climate, geology, forest, and soils, are relatively constant. Topographic characteristics, including (a) hydrological flushing potential (expansion of water table into nitrate-N producing areas); (b) hydrological storage potential (area of wetlands, which can alternatively allow water and nutrients to bypass wetlands when storage capacity is filled with water or to trap them when not filled); and …

Factors Influencing The Distribution Of Brown Trout (Salmo Trutta) In A Mountain Stream: Implications For Brown Trout Invasion Success, Christy Meredith

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Brown trout (Salmo trutta), one of the world’s most successful introduced species in river and lake systems, negatively impacts native species through predation, competition, and systemwide effects. Thus, there is a need to understand factors controlling the distribution of brown trout, in order to prioritize and develop conservation and management strategies. Within the context of invasion success, I investigated how the physical characteristics of the Logan River influence the distribution of brown trout, as well as the potential for brown trout predation on a native fish, the mottled sculpin (Cottus bairdi).

In chapter 1, I evaluated …

The Influence Of Geology And Other Environmental Factors On Stream Water Chemistry And Benthic Invertebrate Assemblages, John R. Olson

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Determining if a stream has been degraded by human activities requires knowing what that stream’s natural water quality and freshwater species composition would likely be without any alteration. However stream natural conditions vary greatly from stream to stream, making predicting natural conditions difficult. To determine natural stream conditions, I developed models to predict natural stream water chemistry at individual streams across the western USA. Specifically, the models predict a stream’s electrical conductivity (a measure of the amount of solids dissolved in water), acid neutralization capacity, and concentrations of calcium, magnesium, sulfate, total phosphorus, and total nitrogen. These models predict chemistry …

Effects Of Varying Land Use On Headwater Stream Fish Assemblages And In-Stream Habitats In Southwestern Louisiana, Alexandra Marie Fitzgerald

LSU Master's Theses

Although watershed land use effects on in-stream fish habitat and fish-macrohabitat associations have been widely studied in the past, low-gradient, coastal Louisiana streams have been poorly described in the literature. In this thesis, I report the results of a two-year study exploring relationships among regional land use, in-stream physical habitat, and headwater stream fish assemblages. In chapter two, I examined in-stream habitat variables such as depth, flow, and substrate combined with three-pass electrofishing depletion estimates at thirteen 100-m stream sites. I used a combination of principle component analysis and structural equation modeling to determine if trends were present in the …