Browsing by Author "Dolph, Christine, L."

Now showing 1 - 4 of 4
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    Characterization of streams and rivers in the Minnesota River Basin Critical Observatory: water chemistry and biological field collections, 2013-2016
    (2017-09-06) Dolph, Christine, L.; Hansen, Amy, T.; Kemmitt, Katie, L.; Janke, Ben; Rorer, Michelle; Winikoff, Sarah; Baker, Anna; Boardman, Evelyn; Finlay, Jacques, C.; dolph008@umn.edu; Dolph, Christine, L.
    This dataset was collected to inform the Water, Sustainability and Climate Minnesota River Basin Observatory, and was supported by the National Science Foundation under Grant No. 1209402 Water, Sustainability and Climate (WSC) – Category 2, Collaborative: Climate and human dynamics as amplifiers of natural change: a framework for vulnerability assessment and mitigation planning. The dataset contains point locations, watershed areas and water quality information for 231 ditch, stream, river and wetland sites located in the Le Sueur River, Chippewa River, Cottonwood River, Cannon River, Wantonwan River and Blue Earth River basins of Minnesota. Study sites ranged in size from 1st order ditches and streams to an 8th order river. Each of these sites was sampled at least once between 2013-2016 (most sites were sampled multiple times) for one or more of the following parameters: 1) water chemistry (total dissolved nitrogen, nitrate-N, nitrite-N, ammonium-N, particulate nitrogen, soluble reactive phosphorus, total dissolved phosphorus, particulate phosphorus, total phosphorus, dissolved organic carbon, dissolved inorganic carbon, particulate carbon, chlorophyll a, total suspended solids, volatile suspended solids, delta-H-2 and delta-O-18 stable isotopes of site water, specific UV absorbance (SUVA) of site water, fluorescence index (FI) of site water); 2) stable isotopes (delta-C-13, delta-N-15, delta-H-2) of invertebrate consumers, particulate carbon and potential food sources; 3) denitrification rates and characteristics of benthic sediment in agricultural drainage ditches; and 4) stream discharge. This dataset also includes spatial data files containing study site locations and watershed areas delineated for each site.
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    The impact of rare taxa on a fish index of biotic integrity
    (2010) Wan, Haibo; Chizinski, Christopher, J.; Dolph, Christine, L.; Vondracek, Bruce; Wilson, Bruce, N.
    The index of biotic integrity (IBI) is a commonly used bioassessment tool that integrates abundance and richness measures to assess water quality. In developing IBIs that are both responsive to human disturbance and resistant to natural variability and sampling error, water managersmust decide how to weigh information about rare and abundant taxa, which in turn requires an understanding of the sensitivity of indices to rare taxa. Herein, we investigated the influence of rare fish taxa (within the lower 5% of rank abundance curves) on IBI metric and total scores for stream sites in two of Minnesota’smajor river basins, the St. Croix (n = 293 site visits) and Upper Mississippi (n = 210 site visits). We artificially removed rare taxa from biological samples by (1) separately excluding each individual taxon that fell within the lower 5% of rank abundance curves; (2) simultaneously excluding all taxa that had an abundance of one (singletons) or two (doubletons); and (3) simultaneously excluding all taxa that fell within the lower 5% of rank abundance curves. We then compared IBI metric and total scores before and after removal of rare taxa using the normalized root mean square error (nRMSE) and regression analysis. The difference in IBI metric and total scores increased as more taxa were removed. Moreover, when multiple rare taxa were removed, the nRMSE was related to sample abundance and to total taxa richness, with greater nRMSE observed in samples with a larger number of taxa or sample abundance. Metrics based on relative abundance of fish taxa were less sensitive to the loss of rare taxa, whereas those based on taxa richness were more sensitive, because taxa richness metrics give more weight to rare taxa compared to the relative abundance metrics.
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    Implications of community concordance for assessing stream integrity at three nested spatial scales in Minnesota, USA
    (2011) Dolph, Christine, L.; Huff, David, D.; Chizinski, Christopher, J.; Vondracek, Bruce
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    The Index of Biological Integrity and the bootstrap: Can random sampling error affect stream impairment decisions?
    (2009) Dolph, Christine, L.; Sheshukov, Aleksey, Y.; Chizinski, Christopher, J.; Vondracek, Bruce; Wilson, Bruce
    Multimetric indices, such as the Index of Biological Integrity (IBI), are increasingly used bymanagement agencies to determine whether surface water quality is impaired. However, important questions about the variability of these indices have not been thoroughly addressed in the scientific literature. In this study, we used a bootstrap approach to quantify variability associated with fish IBIs developed for streams in two Minnesota river basins. We further placed this variability into a management context by comparing it to impairment thresholds currently used in water quality determinations for Minnesota streams. We found that 95% confidence intervals ranged as high as 40 points for IBIs scored on a 0–100 point scale. However, on average, 90% of IBI scores calculated from bootstrap replicate samples for a given stream site yielded the same impairment status as the original IBI score.We suggest that sampling variability in IBI scores is related to both the number of fish and the number of rare taxa in a field collection. A comparison of the effects of different scoring methods on IBI variability indicates that a continuous scoring method may reduce the amount of bias in IBI scores.