Over the last few decades, increased urbanization has led to a new recognition in stream health – the urban stream or the urban stream syndrome. Understanding urban water quality is important for identifying those factors or sources that contribute to impairment. Many streams are listed as impaired because of the increased concentrations of pathogens. While wastewater treatment plants (WWTPs) discharge effluent that has been disinfected, often downstream from WWTPs point sources are high numbers of indicator bacteria, Escherichia coli. This study collected data on the recovery and regrowth of E. coli by collecting ultraviolet light treated effluent from the Carters Creek WWTP and spiked it with three different concentrations of DOC derived from a leaf and grass extract. Escherichia coli were enumerated at 6, 12, 18, 24, 36, 48, and 72 hours. After 6 h growth for each of the grass treatments, except for the control and high grass treatment exceeded the primary contact recreation standard for surface water quality. At 18h the low and high leaf treatments exceeded the primary contact recreation standard for surface water quality. The chemistry of each flask was analyzed for DOC, total N, NO3-N, NH4-N, Na , K , Mg 2, Ca 2, F-, Cl-, SO4-2 and PO4-3 at t=0 and t=72 h. CNP values for both leaf and grass treatments ranged from 2.22 - 36.5. Regrowth was not observed in those treatments with a CNP value below 5. Biodegradability of the treatments was examined to identify the limiting nutrient. By focusing on reducing the CNP value below 5 of the receiving water, recovery and regrowth of E. coli downstream from WWTPs can be reduced. The biodegradability test suggested that in the presence of excess DOC, N is the limiting nutrient. Certain macroinvertebrate species, Ephermeroptera, Trichoptera, and Plecoptera (EPT), are indicators of good stream health. Macroinvertebrates were collected at nine watersheds within the Bryan/College Station area, a rapidly urbanizing community, upstream and downstream from WWTPs and analyzed for relative abundance of pollution intolerant (percent EPT) and pollution tolerant species. All sites downstream from a WWTP had percent EPT present in the collection.

Anthropogenic impacts have degraded the function of many large river-floodplain ecosystems. Habitat rehabilitation/management, in the form of water level management, often emphasize the promotion of wetland vegetation. Wetland management is believed to enhance macroinvertebrate populations. To test this assumption, I evaluated macroinvertebrate response to habitat rehabilitation, habitat type, and vegetation density in Swan Lake, an Illinois River floodplain lake located in Calhoun County, Illinois. Results indicated wetland rehabilitation generally enhanced macroinvertebrate availability for spring migrating waterfowl. Results comparing habitats available at Swan Lake indicated moist soil habitats provided greater abundance and biomass of water column macroinvertebrates in the fall season, while spring was more variable. In addition, benthic macroinvertebrate communities indicated inconsistent differences between habitat types. Fall estimates indicated inundation can be an effective mechanism for controlling the timing of water column macroinvertebrate colonization. Vegetation manipulations did not consistently impact macroinvertebrate taxonomic and functional groups, but results indicated some specific taxonomic groups were influenced by vegetation presence/absence and were correlated (positively or negatively) with coarse organic matter. This research supported the principle that management of habitat and hydrologic regime can be effective tools for improving macroinvertebrate populations in order to optimize nutritional resources for waterfowl.

Conversion to agriculture, land fragmentation, and removal of native grazers have made tallgrass prairies and the streams that drain them one of the most imperiled systems on earth. Patch-burn grazing (PBG), an increasingly common management practice on remaining prairie parcels, has been shown to benefit cattle and grassland birds. However, potential influences of this practice on streams are unknown. To address this, we sampled stream macroinvertebrates and benthic organic matter two years before and three years during PBG on two watersheds with riparian fencing (fenced), two grazed watersheds without riparian fencing (unfenced), and two ungrazed (control) watersheds. Very fine benthic organic matter increased 51% in unfenced watersheds after implementation of PBG, accompanied by a threefold increase in fine organic sediments in the same watersheds. Contribution of fine inorganic sediments to total substrata increased 28% in unfenced watersheds during PBG, while fine inorganic sediments decreased in both the control (18%) and fenced (16%) watersheds. Increases in the contribution of Chironomidae to total macroinvertebrate abundance (18% before, 49% during PBG) and biomass (10% before, 19% during PBG) were evident in unfenced streams. In contrast, abundance of sensitive EPT taxa decreased an order of magnitude from 7,635 to 687 individuals m-2 in unfenced streams, but did not change in fenced and control streams. Increases in tolerant taxa and fine organic and inorganic sediments, along with reductions in metrics of biotic integrity, suggest PBG adversely impacts prairie streams. However, the absence of negative responses in fenced watersheds indicates that riparian fencing can mitigate these impacts by serving as a buffer to prevent excess sedimentation. In order to properly manage remaining tallgrass prairie parcels, it is important to consider both the aquatic and terrestrial components of these systems, as they are tightly linked. Results from this study provide a basis for management and policy decisions regarding remaining grassland watersheds.

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No description available.

The structure and composition of benthic macroinvertebrate communities can vary spatially and over time. Spatial and temporal variation along a stream has many implications for population and community dynamics, which may influence bioassessment programs. I examined variability in the benthic community of eight streams within the Polecat Creek, Virginia watershed. These streams vary in size from 1st to 4th order. The streams were sampled once every season for eleven years using standard bioassessment protocols. Macroinvertebrates were sampled from both sediment and submerged wood habitats at each site. The coefficient of variation (CV) was used to quantify among season, among year and among site variability of eight community metrics from both the sediment and wood samples. ANOVAs were calculated using Tukey post-hoc test to determine if there were statistically significant differences in taxonomic richness and mean CV values across seasons, years and sites for both sediment and wood samples. Sorenson’s Quotient of Similarity was used to examine the extent of differences in the taxonomic composition of the macroinvertebrate communities among the four seasons over the 11 years of the study and among the 8 sampling sites. A high amount of variability was observed among seasons, sites and years. A wide range of CV values was observed among community metrics, with certain metrics exhibiting low overall mean CV values and others exhibiting very high overall mean CV values. It is important to understand the temporal and spatial variability of macroinvertebrates when planning biomonitoring programs.

The objective of this study was to obtain a bioassessment using benthic macroinvertebrates to meet TMDL (Total Maximum Daily Load) criteria for an oligotrophic (Lake Seminary) and an eutrophic (Lake Jesup) freshwater system in Seminole County, Florida. Monthly sampling of the benthic macroinverterbrate communities provided important biological data necessary to construct TMDL protocol and trophic state. Since macroinvertebrates are near the base of the food chain, they not only provide a critical role in the natural flow of energy and cycling of nutrients through the food web, but also provide a good indication of water quality by their presence and abundance. This study suggests that TMDL protocol and reversal trends in eutrophication can be successfully monitored using benthic macroinvertebrate data. Comparative methodology between the LCI and conventional methods indicate that the LCI is a valid, cost-effective and rapid bioassessment method when compared to the conventional method and that the conventional method is an effective tool when more in depth benthic studies are needed as it shows distinct seasonal patterns and accounts for more of the sensitive, intolerant taxa. Furthermore, this type of biological monitoring and trend analysis aids in the implementation of anthropogenic controls that targets waters for TMDLs in suspect systems. When integrated within a watershed management plan, multi-metric indexing functions as an effective overall indicator of the biological condition within a waterbody responding to its watershed.

Water resource management operations have significantly modified river flow regimes globally, prompting widespread lotic ecosystem responses. There is a growing need to better understand how increasingly prevalent hydrological alterations to riverine systems will affect biota dependent on specific elements of river flow regimes. This thesis examines macroinvertebrate community responses to river flow regimes modified by various water resource management operations across southwest England though four detailed investigations. The first study examines the influence of river impoundments and how macroinvertebrate communities differ between regulated and non-regulated sections of river. Findings from this investigation highlight that flow regulation alters the structure and function of faunal assemblages due to significant changes to the flow regime, rather than stream temperature modifications associated with the reservoirs. The second study focusses on groundwater dominated headwater streams transitioning from temporary (i.e. reaches periodically drying positioned furthest upstream) to perennial flow conditions which are subjected to variable groundwater abstraction intensities. The results indicate that macroinvertebrate communities respond significantly to the duration of antecedent flowing conditions and the spatial proximity of sampling sites to perennial sources; but faunal assemblages are not sensitive to groundwater abstraction. The third study examines how communities inhabiting different organic and mineralogical lotic habitats responded to multiple river flow properties (hydrological indices, anthropogenic flow alteration measures and hydraulic variables) in perennial, groundwater dominated systems. The findings highlight that faunal assemblages are most responsive to local hydraulic conditions measured at the point of sampling, rather than antecedent hydrological conditions. The influence of hydraulic properties on communities differs between lotic habitats, highlighting that mineralogical and organic characteristics of riverbeds strongly mediate how biota respond to flow. The final study presents the results of a long-term (1995-2016), region-wide (spanning Dorset, Hampshire and Wiltshire) examination of macroinvertebrate communities inhabiting groundwater dominated rivers and their responses to hydrological variability (including extreme low- and high-flow events) and anthropogenic flow alterations. The results indicate that indices characterising the proportion of discharge added to (through effluent water returns and low-flow alleviation strategies) or removed from the river (via groundwater abstraction) exert profound effects on faunal assemblages over long-term periods. These results provide empirical evidence that reductions in river discharges via groundwater abstraction of approximately 15% have no perceptible negative ecological effects on macroinvertebrate communities. The results from the four detailed investigations are used to develop conceptual models to illustrate how research undertaken within this thesis can be applied more widely. The findings and study designs presented within this thesis could inform surface and groundwater water resource management operations and underpin the development of environmental flow methodologies required to conserve riverine ecosystems globally.

Identifying the processes and mechanisms that govern communities of organisms is the main goal of community ecology. Locally operating mechanisms such as environmental filtering, in which the environment determines what species are found in a given location, as well as regional processes such as dispersal have all been identified as potential drivers of community processes. However, the relative importance of these drivers may vary temporally and spatially. In dendritic stream networks, headwater streams are isolated when compared to more centrally located mainstem stream sections. I investigated the potential for stream networks to influence the relative influence of local and regional processes via a survey and field experiment based approaches. I found that headwater streams can influence mainstem stream communities, potentially as a result of the dispersal of organisms or abiotic materials. Additionally, I demonstrated that macroinvertebrate communities in headwater streams respond more strongly to manipulations of local environment than do mainstem streams, both in terms of community composition as determined taxonomically and as functional traits. These results indicate that headwater streams may be affected differently than mainstem streams by anthropogenic activity and as such, management strategies and restorations may need to be specifically tailored to address the relative influences of local and regional processes at varying points within a stream network. / Ph. D.

Macroinvertebrate assemblage structure was compared from 12 streams differing in urbanization type and degree. Urbanization, both historical and current, was measured using several variables generated from GIS overlays of land cover, aerial photographs, and field exploration in the study watersheds. Quantitative benthic macroinvertebrate samples were taken, and a variety of physicochemical characteristics were measured. Increasing urbanization resulted in a decline in diversity and abundance of intolerant organisms. Streams in industrial areas had greater invertebrate density due to large increases in a few tolerant groups. Urbanization in the watersheds was coupled with changes in the physical and chemical structure of the streams suggesting some possible mechanisms for urbanization impact on stream biota. Multivariate analysis grouped streams based on a number of pollution-sensitive taxa suggesting the utility of this type of approach in analyzing community data. Primary funding for this project was from the Coweeta Hydrologic Lab NSF-LTER grant. Additional funding was provided through a Graduate Research and Development Project grant from the Graduate Student Assembly of Virginia Polytechnic Institute and State University. Matching funds were provided by the Biology Department. / Master of Science