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Albany, NY, United States

McKenna Jr. J.E.,U.S. Geological Survey | Carlson D.M.,NY Environmental Conservation | Payne-Wynne M.L.,New York University
Diversity and Distributions

Aim: Rare aquatic species are a substantial component of biodiversity, and their conservation is a major objective of many management plans. However, they are difficult to assess, and their optimal habitats are often poorly known. Methods to effectively predict the likely locations of suitable rare aquatic species habitats are needed. We combine two modelling approaches to predict occurrence and general abundance of several rare fish species. Location: Allegheny watershed of western New York State (USA) Methods: Our method used two empirical neural network modelling approaches (species specific and assemblage based) to predict stream-by-stream occurrence and general abundance of rare darters, based on broad-scale habitat conditions. Species-specific models were developed for longhead darter (Percina macrocephala), spotted darter (Etheostoma maculatum) and variegate darter (Etheostoma variatum) in the Allegheny drainage. An additional model predicted the type of rare darter-containing assemblage expected in each stream reach. Predictions from both models were then combined inclusively and exclusively and compared with additional independent data. Results: Example rare darter predictions demonstrate the method's effectiveness. Models performed well (R2 ≥ 0.79), identified where suitable darter habitat was most likely to occur, and predictions matched well to those of collection sites. Additional independent data showed that the most conservative (exclusive) model slightly underestimated the distributions of these rare darters or predictions were displaced by one stream reach, suggesting that new darter habitat types were detected in the later collections. Main conclusions: Broad-scale habitat variables can be used to effectively identify rare species' habitats. Combining species-specific and assemblage-based models enhances our ability to make use of the sparse data on rare species and to identify habitat units most likely and least likely to support those species. This hybrid approach may assist managers with the prioritization of habitats to be examined or conserved for rare species. © 2013 John Wiley & Sons Ltd. Source

Smith A.J.,NY Environmental Conservation | Tran C.P.,New England Interstate Water Pollution Control Commission | Tran C.P.,New York University
Journal of the North American Benthological Society

Cultural eutrophication of surface waters has become a major source of water-quality impairment throughout the US. In response, the US Environmental Protection Agency (USEPA) has devised a national strategy for the development of regional nutrient criteria. Our study is part of New York State's effort to revise its narrative nutrient standard for N and P and is based on the USEPA's recommended weight-of-evidence approach. The objective of our investigation was to identify nutrient thresholds based on a final weighted average of results from percentile analysis, nonparametric deviance reduction (changepoint), and cluster analysis. The thresholds were determined from shifts in biological community structure (benthic macroinvertebrate and diatom) related to water-column nutrient data from 40 large river sites throughout New York State. USEPA's percentile analysis yielded possible criteria of 0.023 mg total P (TP)/L, 0.51 mg total N (TN)/L, 0.16 mg NO3-N /L, and 2.4 mg chlorophyll a (chl a)/m3. Threshold responses in benthic macroinvertebrate metrics at the 50th percentile occurred at concentrations between 0.009 and 0.07 mg TP/L, 0.41 and 1.2 mg TN/L, 0.18 and 0.55 mg NO3-N/L, and 2.1 mg chl a/m3. Cluster analysis yielded 3 groups of sites based on macroinvertebrate and diatom taxa. The median nutrient values of the medium-nutrient-condition site clusters were used to set criteria for TP and TN. For site clusters based on macroinvertebrate data these values were 0.037 mg TP/L and 0.68 mg TN/L. For clusters based on diatom data these were 0.037 mg TP/L and 0.78 mg TN/L. Based on the weight-of-evidence approach and results from all 3 methods, the proposed guidance values for nutrients in large rivers are 0.03 mg TP/L, 0.7 mg TN/L, 0.3 mg NO 3-N/L, and 2.2 mg chl a/m3. These values are similar to those derived by others and provide meaningful nutrient endpoints that would be protective of aquatic life in large rivers. © 2010 The North American Benthological Society. Source

Rozell D.,NY Environmental Conservation
Journal of Environmental Engineering

An arsenic filtration experiment using iron oxide coated sand was modeled using the USGS geochemical program PHREEQC. Despite some uncertainty regarding the initial conditions of the groundwater and the simplicity of the model, it replicated the experimental results within 10%. The original experiment filtered 165 bed volumes to concentrations less than 0.01 mg/L As and approximately 210 bed volumes to 0.05 mg/L As. The model filtered 168 bed volumes to 0.01 mg/L As and 228 bed volumes to 0.05 mg/L. © 2010 ASCE. Source

Langwig K.E.,Boston University | Langwig K.E.,University of California at Santa Cruz | Frick W.F.,University of California at Santa Cruz | Bried J.T.,Oklahoma State University | And 3 more authors.
Ecology Letters

Disease has caused striking declines in wildlife and threatens numerous species with extinction. Theory suggests that the ecology and density-dependence of transmission dynamics can determine the probability of disease-caused extinction, but few empirical studies have simultaneously examined multiple factors influencing disease impact. We show, in hibernating bats infected with Geomyces destructans, that impacts of disease on solitary species were lower in smaller populations, whereas in socially gregarious species declines were equally severe in populations spanning four orders of magnitude. However, as these gregarious species declined, we observed decreases in social group size that reduced the likelihood of extinction. In addition, disease impacts in these species increased with humidity and temperature such that the coldest and driest roosts provided initial refuge from disease. These results expand our theoretical framework and provide an empirical basis for determining which host species are likely to be driven extinct while management action is still possible. Copyright © 2012 Blackwell Publishing Ltd/CNRS159 September 2012 10.1111/j.1461-0248.2012.01829.x Letter Letters © 2012 Blackwell Publishing Ltd/CNRS. Source

Analysis of PAMS (Photochemical Assessment Monitoring Stations) data at several coastal sites reveals large weekday/weekend differences in gasoline related hydrocarbons. Elevated concentrations of gasoline related constituents, including alkanes, alkenes, and aromatics, are observed on weekends at the PAMS monitors at Sherwood Island State Park in Westport, CT and at Newbury, MA. An analysis of the ratio of the concentrations of 2,3-dimethylbutane to 2,2-dimethylbutane indicates these compounds are freshly emitted, and an investigation in conjunction with wind data shows that the elevated concentrations are associated primarily with onshore winds. These elevated concentrations are most likely due to weekend recreational boating. © 2013 Elsevier Ltd. Source

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