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Coastal wetland vegetation along the Great Lakes differs strongly with latitude, but most studies of Great Lakes wetland condition have attempted to exclude the effect of latitude to discern anthropogenic effects on condition. We developed an alternative approach that takes advantage of the strong relationship between latitude and coastal wetland floristic condition. Latitude was significantly correlated with 13 of 37 environmental variables tested, including growing degree days, agriculture, atmospheric deposition, nonpoint-source pollution, and soil texture, which suggests that latitude is a good proxy for several environmental drivers of vegetation. Using data from 64 wetlands along the U.S. coast of Lakes Huron,...
We evaluated the relationships between landscape characteristics and lake water quality in receiving waters by regressing four water quality responses on landscape variables that were measured for whole watersheds and three different buffer distances (30, 60, and 120 m). Classical percolation theory was used to conceptualize nutrient pathways and to explain nonlinear responses. The response variables were total nitrogen (TN), total phosphorus (TP), chlorophyll-a (Chl-a), and Secchi transparency (SD). Landscape data were obtained from satellite image-derived maps of 130 watersheds in Iowa using geographic information systems software. We developed regression models with a stepwise protocol selecting the optimal number...
The high load of suspended sediments in Kansas rivers and reservoirs has raised many concerns about the quality of the state's water supply. Erosion originating in pastures, croplands, gullies and channel-banks accounts for the majority of the suspended sediment load. Pasture and cropland adjacent to river and stream banks without riparian buffers increase de-stabilization allowing for bank deterioration and contribute non-point source pollutants such as fertilizers, pesticides and fecal matter. Determining high-risk areas along rivers and tributaries for either riparian remediation or bank stabilization is part of our research. Using GIS technology with present day and historical aerial images, high risk areas...
Results from the generation of a multidecadal gridded climatic dataset for 57 yr (1950–2006) of daily and monthly precipitation (PTotal), maximum temperature (Tmax), and minimum temperature (Tmin) are presented for the important agricultural and forest products state of Wisconsin. A total of 176 climate stations were used in the final gridded dataset that was constructed at 8-km (5.0′) latitude–longitude resolution using an automated inverse distance weighting interpolation. Accuracy statistics for the interpolated data were based on a rigorous validation step using 104 first- and second-order climate observation stations withheld in the production of the gridded dataset. The mean absolute errors (MAE) for daily...
The ecological effects of spawning runs of native Pacific salmon (Oncorhynchus spp.) on stream ecosystems of the Pacific Northwest and Northern Pacific Rim have been studied extensively. However, little is known about how nonnative Pacific salmon affect stream ecosystems in the Great Lakes Basin, especially given the difference in environmental context between the regions. Mechanisms by which salmon spawners alter stream ecosystems include nutrient enrichment from excretion by live adults, carcass decomposition, and physical disturbance of the substrate during redd construction. The objective of our study was to quantify changes in water chemistry and benthic periphyton in 3 streams in northern Michigan that have...
Reliable water quality models are needed to forecast the water quality consequences of different agricultural nutrient management scenarios. In this study, the Soil and Water Assessment Tool (SWAT), version 2000, was applied to simulate streamflow, riverine nitrate (NO3) export, crop yield, and watershed nitrogen (N) budgets in the upper Embarras River (UER) watershed in east-central Illinois, which has extensive maize-soybean cultivation, large N fertilizer input, and extensive tile drainage. During the calibration (1994–2002) and validation (1985–1993) periods, SWAT simulated monthly and annual stream flows with Nash-Sutcliffe coefficients (E) ranging from 0.67 to 0.94 and R 2 from 0.75 to 0.95. For monthly and...
The article offers information on the stimulation of phosphorus transport in an agricultural watershed using the water erosion prediction project (WEEP) model. The authors state that the WEEP model has been tested for its ability to predict soil erosion, runoff, and sediment delivery over a wide range of conditions and scales for both hillslopes and watersheds. They explain that the study aims to program, incorporate, and test the ability of WEEP to estimate total phosphorus (TP) loss with sediment at the small watershed scale. They also point out that the study suggests that further developments of the phosphorus model could lead to the incorporation of a nutrient cycling routine in the WEEP model to adjust the...
Management practices may affect the potential for nitrate leaching from agricultural systems. Two studies are discussed that used plot-size lysimeters on loamy sand and clay loam soil in Northern New York. One was conducted from 1991 to 1994 and involved sod plowing and the use of three rates of fertilizer on maize (Zea mays L). The other study was conducted from 1997 to 2000 and quantified N-leaching losses under maize and orchardgrass (Dactylis glomerata L.) as affected by the timing of manure application. These studies showed that timing and rate of N fertilizer and manure additions, timing of green-manure incorporation, and soil type strongly influenced N-leaching losses. Losses from fall-applied N sources were...
Increased awareness of the contributions of non point source runoff to the degradation of water quality in the Mississippi River and Gulf of Mexico emphasizes the need to increase conservation practices that reduce nutrient export from agricultural lands. To achieve long- term conservation goals in agricultural landscapes, it is important to understand farmers' perspectives on what practices are effective, practical, and economically attainable. We conducted a series of surveys, interspersed with focused outreach, of farmers in two agricultural watersheds in central Illinois in an attempt to better understand how outreach influenced their views on and adoption of conservation practices. Programs differed between...
Riparian buffers are designed as management practices to increase infiltration and reduce surface runoff and transport of sediment and nonpoint source pollutants from crop fields to adjacent streams. Achieving these ecosystem service goals depends, in part, on their ability to remove water from the soil via transpiration. In these systems, edges between crop fields and trees of the buffer systems can create advection processes, which could influence water use by trees. We conducted a field study in a riparian buffer system established in 1994 under a humid temperate climate, located in the Corn Belt region of the Midwestern U.S. (Iowa). The goals were to estimate stand level transpiration by the riparian buffer,...
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...
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 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...