Effects of beaver dam analogs on stream ecosystem function of Crab Creek, Washington State

This study documents the effects of beaver dam analogs (BDAs) on nutrient transport, fish community composition, macroinvertebrate drift, and benthic macroinvertebrate communities of Crab Creek, WA, USA. In 2019, the U.S. Fish and Wildlife Service (USFWS), and Natural Resource Conservation Service (NRCS) placed 25 BDAs in Crab Creek on a section of private land near Harrington, WA. Beaver dam analogs are structures placed in streams to mimic the ecosystem effects of beaver activity and are increasingly used as a stream restoration technique. The primary goals of placing these BDAs in the stream was to impound sediment and create a new floodplain at the currently incised stream channel. While BDAs are increasingly used as a stream restoration technique, there is limited research on their impacts on stream ecosystem function. Investigating how BDAs effect nutrient retention, macroinvertebrate communities, and fish community composition will help inform practitioners about the effectiveness of this restoration strategy. Crab Creek had a significantly higher density of red sided shiners (Richardsonius balteatus) (p=0.00175) in the BDA reach compared to control reaches. When comparing the BDA reach to the control sites, there were no significant differences in nutrient retention in the BDA site. Macroinvertebrate community response had limited statistically significant differences when compared to the control sites. However, there were significant changes from 2009 to 2020 when comparing benthic macroinvertebrate assemblages, probably in response to factors other than BDA installation. Altogether, few effects of BDA installation were detected for nutrient retention, macroinvertebrate communities, and fish community composition. BDAs are a process-based restoration technique that requires a significant change in physical ecosystem parameters before any changes are likely to be seen in the biological community or ecosystem processes. Changes to geomorphology of the stream could potentially take time, as these restoration techniques require stream energy to alter the physical parameters of the stream. Since BDA installation in Crab Creek, no significant high flow events have occurred. Without early spring flood events, changes in the nutrient dynamics, and macroinvertebrates communities could be subtle, or undetectable. This research will ultimately contribute to the current limited understanding of the effects of BDAs on stream ecosystem function

Effect of Vegetation on the Ontogeny to Piscivory in Juvenile Largemouth Bass

Largemouth Bass (Micropterus salmoides) are an economically important gamefish species in North America and as such are a focal species for managers. A frequent bottleneck to their recruitment is overwinter survival in their first year of life. Early ontogeny to piscivory provides increased overwinter survival through growth and accumulation of lipids. This ontogeny is slowed by dense and complex vegetative habitats according to anecdotal field evidence. I chose to address two issues: 1) does vegetation density affect the foraging return of piscivorous juvenile Largemouth Bass? 2) Does vegetation density affect the timing of the ontogeny to piscivory in juvenile Largemouth Bass? To answer objective 1) I conducted foraging trials using piscivorous juvenile Largemouth Bass and Juvenile Fathead Minnows (Pimephales promelas) in eight treatments of varying simulated vegetation densities (0, 125, 250, 500, and 1,000 stems/m2) and complexities (simple and complex). Piscivorous Largemouth Bass consumed the most Fathead Minnows in the 125 stems/m2 simple treatment and the least in the 0 stems/m2 treatment. Indicating that juvenile Largemouth Bass forage least efficiently on Fathead Minnows in habitats with no complexity. To answer objective 2) I conducted enclosure experiments across 5 weeks of the typical time frame (mid-summer) that juvenile Largemouth Bass would transition to piscivory. Thirty-two enclosures were constructed across two 0.10 hectare ponds and treated with four stem densities of simulated vegetation (0, 50, 250, and 500 stems/m2). Three juvenile Largemouth Bass and 30 juvenile Bluegill (Lepomis macrochirus) were added to each enclosure. All fish were sampled twice per week. Largemouth bass growth was measured as total length (mm) and diets were collected via gastric lavage. Bluegill densities were manipulated to stay consistent. It was found that Largemouth Bass switched to piscivory during the second week in the 0, 50, and 500 stems/m2 treatments but did not completely switch in the 250 stems/m2 treatment. Growth mirrored this pattern where Largemouth Bass grew less in the 250 stems/m2 treatment. Differing results in these two experiments suggest that vegetation density does affect the foraging rate and subsequent ontogeny to piscivory in juvenile Largemouth Bass. However, it has an interactive effect with available fish prey species.Natural Resources and Ecology Managemen

A River Continuum Analysis of an Anthropogenically-Impacted System: The Little Bear River, Utah

In September 2012 the Aquatic Ecology Practicum class from Utah State University studied the 51km river continuum of the Little Bear River located in northern Utah (Figure 1). The relatively pristine headwaters of the river begin in the Wasatch Mountain Range at an altitude of 1800 m. The river flows northward into Cache Valley where it terminates in Cutler Reservoir (1345 m elevation). Agricultural development and urbanization have modified the natural terrain and chemical characteristics of the river, and Hyrum Reservoir, located midway along the gradient causes a discontinuity in river processes. The results from analyses of stream condition indicators from up to eleven stations along the gradient were interpreted within the context of the River Continuum Concept (Vannote et al. 1980) and the Serial Discontinuity Hypothesis (Ward and Stanford 1983)

Toxicity evaluation of metal plating wastewater employing the Microtox® assay: A comparison with cladocerans and fish

The relative sensitivity of the Microtox assay is closely related to the type of toxicant, and hence its utility in biomonitoring effluents is better evaluated on a case-by-case basis. The Microtox® assay, employing the marine bacterium Vibrio fischeri , was evaluated for its applicability in monitoring metal plating wastewater for toxicity. The results of the Microtox assay after 5, 15, and 30 min of exposure, were compared with data obtained from conventional whole effluent toxicity testing (WET) methods that employed Daphnia magna , Ceriodaphnia dubia , and the fathead minnow ( Pimephales promelas ). The Microtox assay produced notably comparable EC50 values to the LC50 values of the acute fathead minnow toxicity test (<0.5 order of difference). The Spearman's rank correlation analyses showed that the bacterial assay, regardless of exposure duration, correlated better with the acute fish than the daphnid results ( p <0.05). These observations were consistent to other studies conducted with inorganic contaminants. The relative sensitivity of the 30-min Microtox assay was within the range of the two frequently used acute daphnid/fish toxicity tests. In conclusion, the Microtox assay correlated well with the acute fathead minnow data and is well suited for toxicity monitoring for these types of industrial wastes. © 2001 John Wiley & Sons, Inc. Environ Toxicol 16: 136–141, 2001Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/35240/1/1017_ftp.pd

Anthropogenically Altered Land and its Effect on δ15N Values in Periphyton on a Fourth Order Stream in Utah’s Cache Valley

The Little Bear River is a tributary to the Bear River that drains the south end of the Cache Valley in Northern Utah. The upper elevations are more pristine and are made up of mostly forested mountainous terrain with some grazing activity. The lower elevations are comprised of low gradient agricultural and urban parcels. Anthropogenically influenced landscapes can result in higher nitrogen inputs to streams, and these increases are often marked by an increase in the heavy-nitrogen isotope, δ15N. This study looked at the concentration of δ15N in periphyton on the river bed. These concentrations were then compared to anthropogenic land use in the surrounding watershed. δ15N values in the periphyton were significantly correlated with increasing percentages of anthropogenically affected land use in the Little Bear River watershed. It is likely that anthropogenic land uses (manure fertilization and wastewater treatment) caused the enrichment in δ15N concentrations

An Analysis of Benthic Invertebrate Response to Nutrient Mitigation in the Wenatchee River Tributaries

This project will analyze responses of benthic invertebrates to an ongoing salmon restoration project in the Chiwawa River, a tributary of the Wenatchee River. The Columbia Cascade Fisheries Enhancement Group (CCFEG) is adding nutrients in the form of salmon carcass analogs to a reach of the Chiwawa River each fall from 2018 through 2022, with the goal of increasing growth and overwinter survival of juvenile salmonids. This study will use a Before-After Control-Impact study design to measure the effects of nutrient mitigation on the benthic macroinvertebrates. I will use previous data, collected before nutrient mitigation was implement, for five rivers in the Wenatchee River Basin: Nason Creek, White River, Upper and Little Wenatchee Rivers, and the Chiwawa River as a reference to determine if nutrient mitigation has increased invertebrate populations that serve as food for juvenile salmonids, or altered the composition of the invertebrate community. Specifically, I will investigate whether there is stimulation of invertebrate production by nutrient mitigation, and whether invertebrate communities indicate any changes to water quality or ecosystem health in the nutrient mitigation reach of the Chiwawa River. These findings will benefit the CCFEG by evaluating the effectiveness of nutrient enhancement. This research will also contribute to our understanding of how nutrient mitigation effects macroinvertebrate communities over a large special scale