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This study evaluated the relations between algal, invertebrate, and fish assemblages and physical environmental characteristics of streams at the reach, segment, and watershed scale in agricultural settings in the Midwest. The 86 stream sites selected for study were in predominantly agricultural watersheds sampled as part of the U.S. Geological Survey's National Water-Quality Assessment Program. Species abundance and over 130 biological metrics were used to determine which aspects of the assemblages were most sensitive to change at the three spatial scales. Digital orthophotograph-based riparian land use/land cover was used for analyses of riparian conditions at the reach and segment scales. The percentage area...
Abstract: A significant number of historically existing wetlands that naturally stored rainwater and attenuated flood peaks have now been drained and employed as new farming areas. Beyond the water quality and flow problem, this has resulted in loss of natural habitats of diverse ecological species. Restoring wetlands have hence been proposed as a potential conservation strategy to help attenuate many of these problems. In this study a spatial, multi-objective optimization study of new potential wetlands was carried out to achieve biodiversity improvements in addition to flood reduction benefits and water quality improvements. The Soil and Water Assessment Tool (SWAT) was used to simulate flow and water quality,...
Seasonal hypoxia in the northern Gulf of Mexico has been linked to increased nitrogen fluxes from the Mississippi and Atchafalaya River Basins, though recent evidence shows that phosphorus also influences productivity in the Gulf. We developed a spatially explicit and structurally detailed SPARROW water-quality model that reveals important differences in the sources and transport processes that control nitrogen (N) and phosphorus (P) delivery to the Gulf. Our model simulations indicate that agricultural sources in the watersheds contribute more than 70% of the delivered N and P. However, corn and soybean cultivation is the largest contributor of N (52%), followed by atmospheric deposition sources (16%); whereas...
Whitefish Lake, which is officially named Bardon Lake, is an oligotrophic, soft-water seepage lake in northwestern Wisconsin, and classified by the Wisconsin Department of Natural Resources as an Outstanding Resource Water. Ongoing monitoring of the lake demonstrated that its water quality began to degrade (increased phosphorus and chlorophyll a concentrations) around 2002 following a period of high water level. To provide a better understanding of what caused the degradation in water quality, and provide information to better understand the lake and protect it from future degradation, the U.S. Geological Survey did a detailed study from 2004 to 2008. The goals of the study were to describe the past and present...
Renewable fuel production, particularly grain-based ethanol, is expanding rapidly in the USA. Although subsidized grain-based ethanol may provide a competitively priced transportation fuel, concerns exist about potential environmental impacts. This contribution focuses on potential water quality implications of expanded grain-based ethanol production and potential impacts of perennial-grass–based cellulosic ethanol. Expanded grain-based ethanol will increase and intensify corn production. Even with recommended fertilizer and land conservation measures, corn acreage can be a major source of N loss to water (20–40 kg ha-1 yr-1). A greater acreage of corn is estimated to increase N and P loss to water by 37% (117 million...
Abstract (from http://www.tandfonline.com/doi/full/10.1080/00028487.2016.1150879): Long-term sampling of fisheries data is an important source of information for making inferences about the temporal dynamics of populations that support ecologically and economically important fisheries. For example, time series of catch-per-effort data are often examined for the presence of long-term trends. However, it is also of interest to know whether certain sampled locations are exhibiting temporal patterns that deviate from the overall pattern exhibited across all sampled locations. Patterns at these “unusual” sites may be the result of site-specific abiotic (e.g., habitat) or biotic (e.g., the presence of an invasive species)...
Abstract (from ESA): Estimating population size and resource selection functions (RSFs) are common approaches in applied ecology for addressing wildlife conservation and management objectives. Traditionally such approaches have been undertaken separately with different sources of data. Spatial capture–recapture (SCR) provides a hierarchical framework for jointly estimating density and multi‐scale resource selection, and data integration techniques provide opportunities for improving inferences from SCR models. Despite the added benefits, there have been few applications of SCR‐RSF integration, potentially due to complexities of specifying and fitting such models. Here, we extend a previous integrated SCR‐RSF model...
Although drought is a natural part of climate across the north-central United States, how drought is experienced and responded to is the result of complex biophysical and social processes. Climate change assessments indicate drought impacts will likely worsen in the future, which will further challenge decision-making. Here, a drought management decision typology is empirically developed from synthesis of three in-depth case studies using a modified grounded-theory approach. The typology highlights 1) the entity or entities involved, 2) management sectors, 3) decision types, 4) spatial and temporal scale(s) of decision-making, and 5) barriers that inhibit decision-making. Findings indicate similarities in decision...
Since the mid 1990's, Lake Erie has experienced seasonal eutrophication. This investigation was designed to look at potential causes for eutrophication in Lake Erie. It was also designed to see if any correlations exist between agriculturally applied fertilizers (including sewage sludge) and cyanobacterial blooms in the Western Basin of Lake Erie that occurred during the months of July, August, and September for the years 1999-2003. An algorithm was used on available LANDSAT Thematic Mapper (TM) frames to monitor phycocyanin growth caused by cyanobacteria. These images were analyzed in conjunction with Maumee River water quality data, planted winter wheat, local weather data, and records of agriculturally applied...
Runoff losses of nitrogen (N) and phosphorus (P) from field applied manure can contribute to surface water pollution. Grass hedges may reduce runoff losses of nutrients and sediment. The objective of this study was to evaluate the effects of narrow switchgrass (Panicum virgatum L.) hedges (−0.75 m wide) on the transport of P and N from a field receiving beef cattle feedlot manure under tilled and no-till conditions. This study was conducted on a steep (12 % average slope) Monona silt loam (fine-silty, mixed, superactive, mesic Typic Hapludolls) soil near Treynor, Iowa. The experiment was a split-plot with no-till and disked systems as main plots and subplots of manure, fertilizer, and check with or without a grass...
Impacts of climate change on natural resources need to be evaluated in a range of geography and agricultural systems for better conservation planning. The objectives of this paper were to evaluate spatial sensitivity of predicted soil loss and runoff to climate change at large scales, and to simulate the “regional” impacts of climate change on soil erosion on the southern Great Plains. Relative climate changes at three spatial scales between 1950 to 99, and 2070 to 99, projected using HadCM3 under the A2a, B2a, and GGa1 emission scenarios, were used to generate changed climates for Chickasha, Oklahoma. The Water Erosion Prediction Project (WEPP) model was run for each climate scenario at three spatial scales with...