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Madison, WI, United States

O'Donnell D.M.,Upstate Freshwater Institute | Effler S.W.,Upstate Freshwater Institute | Perkins M.,Upstate Freshwater Institute | Strait C.,Upstate Freshwater Institute | And 2 more authors.
Journal of Great Lakes Research

Optical properties have fundamental importance to water quality, ecology, and remote sensing initiatives. Paired measurements of optically active constituents (OACs), and inherent optical properties (IOPs) and apparent optical properties (AOPs), were made in September 2010 across the optical gradients of Green Bay, extending from the Fox River to Sturgeon Bay (8 sites), and for three near-shore locations in the main basin of Lake Michigan. The array of laboratory and in situ measurements provided a robust characterization of the underwater and emergent light fields of these waters with respect to magnitudes and spectral features of the OACs, IOPs and AOPs. These measurements resolved the character and possible origins of the major gradients within the bay (5 to 10-fold differences) and the substantial differences between the bay and the main basin. The credibility of the characterizations was supported through closure analyses which demonstrated: (1) the approach to equivalence between various field and laboratory measurements, and (2) good matches of AOP observations by values predicted from measured IOPs using accepted radiative transfer expressions. The bay was demonstrated to be an optically complex case 2 system, with uncoupled variations along the spatial gradient(s) in OACs of phytoplankton biomass, colored dissolved organic material, and non-algal particulates. The documented spatial differences in optical properties rival those reported in much larger marine surveys. Radiative transfer expressions are used to predict changes in AOPs of the downwelling (underwater) attenuation coefficient and remote sensing signal in response to scenarios of changes in levels of OACs of potential ecological and management interest. © 2013 Elsevier B.V. Source

van Egeren S.J.,801 Progress Rd. | Dodson S.I.,University of Wisconsin - Madison | Torke B.,3119 W. Petty Road | Maxted J.T.,Cadmus Group Inc.

Zooplankton community composition can be related to natural environmental factors such as lake morphology, lake landscape position, and water chemistry as well as anthropogenic factors such as agricultural and urban land-use. We hypothesized that within-lake factors, such as water chemistry, lake morphology, and human land-use would each be related to zooplankton community structure, but that watershed land-use would be the strongest correlate in southeast Wisconsin lakes. Zooplankton samples, collected every 3 months over a year, from 29 lakes were used to determine how lake and watershed morphology, water quality, and land-use were related to zooplankton community structure in the heavily developed Southeast Wisconsin Till Plain Ecoregion. Forward selection and a variation partitioning procedure were used to determine relative and shared contributions of each suite of variables in predicting zooplankton community structure. Redundancy analysis was used to characterize dominant gradients in pelagic zooplankton communities and related environmental factors and land-use. The major correlates of community structure included summer phosphorus, lake depth and surface area and urban and natural land. Variation partitioning illustrated that phosphorus alone accounts for the greatest part (12%) of community structure. Urban land-uses (residential, commercial and paved land) and lake morphology partially explain zooplankton community variation through combined effects with phosphorus. Small cladocerans and Skistodiaptomus pallidus were associated with higher phosphorus, shallow depth and higher urban land-use, while Daphnia pulicaria dominates in deep lakes with lower phosphorus and less urban land-use. This study contributes to the understanding of factors affecting zooplankton community structure in a largely human developed region and illustrates the importance of eutrophication in structuring zooplankton community composition. © 2011 Springer Science+Business Media B.V. Source

Grear D.A.,University of Wisconsin - Madison | Samuel M.D.,U.S. Geological Survey | Scribner K.T.,Michigan State University | Weckworth B.V.,University of Calgary | Langenberg J.A.,801 Progress Rd.
Journal of Applied Ecology

Social organization and interactions among individuals are suspected to play important roles in the transmission and potential management of wildlife diseases. However, few studies have been conducted to evaluate sociality in wildlife disease transmission. We evaluated the hypothesis of socially facilitated transmission of chronic wasting disease (CWD) among adult female white-tailed deer using spatial location and genetic relatedness for 1387 female deer, and spatial locations of 1321 adult male deer harvested during 2002-2004 CWD control efforts in Wisconsin, USA. Genetically related female deer were significantly clustered at distances of <3·2 km. However, spatial autocorrelation based on maternally inherited mitochondrial DNA was 50-fold higher than relatedness estimated from microsatellite loci, indicating spatial overlap of females from different social groups with high rates of male-mediated dispersal and gene flow among groups. Probability of CWD infection in adult females was significantly increased by closely related (full-sibling, mother-offspring) infected females that were both spatially proximate (≤3·2 km) and farther distant. To a minor extent, the probability of infection was also influenced by the number of nearby infected females (≤3·2 km), but not by the number of infected males. Direct deer-to-deer transmission of CWD between closely related female deer may be an important route of local CWD transmission.. Synthesis and applications. Random mixing and infectious contact may be inadequate models for CWD transmission and disease spread in female deer. Frequency-dependent CWD transmission may be important for females because infectious contacts are limited between members of different female social groups, even if ranges overlap. Given that our data demonstrate a strong relationship between infection probability and female relatedness, CWD management should consider female harvest to maintain smaller female social groups and reduce contact among female deer. However, evaluation of the effects of this strategy on deer social behaviour and contact is needed. © 2010 The Authors. Journal compilation © 2010 British Ecological Society. Source

Gyawali R.,801 Progress Rd. | Gyawali R.,Michigan Technological University | Griffis V.W.,Michigan Technological University | Watkins D.W.,Michigan Technological University | Fennessey N.M.,University of Massachusetts Dartmouth
Hydrological Processes

Hydro-climatic impacts in water resources systems are typically assessed by forcing a hydrologic model with outputs from general circulation models (GCMs) or regional climate models. The challenges of this approach include maintaining a consistent energy budget between climate and hydrologic models and also properly calibrating and verifying the hydrologic models. Subjective choices of loss, flow routing, snowmelt and evapotranspiration computation methods also increase watershed modelling uncertainty and thus complicate impact assessment. An alternative approach, particularly appealing for ungauged basins or locations where record lengths are short, is to predict selected streamflow quantiles directly from meteorological variable output from climate models using regional regression models that also include physical basin characteristics. In this study, regional regression models are developed for the western Great Lakes states using ordinary least squares and weighted least squares techniques applied to selected Great Lakes watersheds. Model inputs include readily available downscaled GCM outputs from the Coupled Model Intercomparison Project Phase 3. The model results provide insights to potential model weaknesses, including comparatively low runoff predictions from continuous simulation models that estimate potential evapotranspiration using temperature proxy information and comparatively high runoff projections from regression models that do not include temperature as an explanatory variable. © 2014 John Wiley & Sons, Ltd. Source

Robinson S.J.,University of Wisconsin - Madison | Samuel M.D.,U.S. Geological Survey | Rolley R.E.,801 Progress Rd. | Shelton P.,University of Illinois at Springfield
Landscape Ecology

Animal movement across the landscape plays a critical role in the ecology of infectious wildlife diseases. Dispersing animals can spread pathogens between infected areas and naïve populations. While tracking free-ranging animals over the geographic scales relevant to landscape-level disease management is challenging, landscape features that influence gene flow among wildlife populations may also influence the contact rates and disease spread between populations. We used spatial diffusion and barriers to white-tailed deer gene flow, identified through landscape genetics, to model the distribution of chronic wasting disease (CWD) in the infected region of southern Wisconsin and northern Illinois, USA. Our generalized linear model showed that risk of CWD infection declined exponentially with distance from current outbreaks, and inclusion of gene flow barriers dramatically improved fit and predictive power of the model. Our results indicate that CWD is spreading across the Midwestern landscape from these two endemic foci, but spread is strongly influenced by highways and rivers that also reduce deer gene flow. We used our model to plot a risk map, providing important information for CWD management by identifying likely routes of disease spread and providing a tool for prioritizing disease monitoring and containment efforts. The current analysis may serve as a framework for modeling future disease risk drawing on genetic information to investigate barriers to spread and extending management and monitoring beyond currently affected regions. © 2013 Springer. Source

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