USEPA Region 7 Regional Technical Assistance Group

Transcription

1 USEPA Region 7 Regional Technical Assistance Group Debbie Baker and Donald Huggins P C C Central Plains Center for BioAssessment, Kansas Biological Survey B Gary Welker USEPA Region 7, Kansas City, KS

2 CPCB History Created in 1998 at the Kansas Biological Survey. Facilitate coordination of regional-based nutrient criteria and biocriteria for waterbodies of USEPA Region 7.

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5 USEPA Region 7

6 Streams

7 Database 18 sources of data > 54, sampling events 2235 sites Level 3 Omernik ecoregions Total Nitrogen Total Phosphorus Chlorophyll a (suspended and benthic) Turbidity Fish Macroinvertebrates

8 Stream classification Strahler Order (1 8) Watershed size (136 ha 8,159,84 ha) Ecoregion (14 Level III) Reference sites Best professional judgment (n=254) Trisection based on suspended chlorophyll a (n=1) Trisection based on macroinvertebrate richness (n=169) 25 th percentile for each parameter

9 16 Frequency Distribution of Watershed Size Number of Watersheds Log of Watershed Size in Hectares 16% <12 mi 2 38% mi 2 31% mi 2 15% >1234 mi 2 7 8

10 Chemistry Database Raw records (>54,) of chemistry parameters compiled into medians for each variable for each site 2235 records, each site represented once. Only sites with > 5 records per site considered for analyses.

11 Biology Databases Separate database of taxa matched with chemistry sampling events taken < 1 month prior to taxa samples Bugs & chemistry: 57 sampling events (348 sites). Fish & chemistry: 1179 events (51 sites).

12 Preliminary Analyses ANOVA, ANCOVA, GLM ANOVA Linear regression with chlorophyll response Conclusions Use all seasons. Significant differences among ecoregions. Significant differences among orders appear to be groupings: 1 5 and 6 8.

13 Descriptive Statistics 25th%ile BPJ tri chla* tri macro* n 25th n med n med n med TN (mg/l) TP (mg/l) turbidity (NTU) sestonic chla (ug/l) benthic chla (mg/m2) macroinv. total rich fish total rich * Trisection based on the best third of the sites for suspended chlorophyll a or macroinvertebrate taxa richness.

14 Potential benchmark values for nutrient stressors and other associated variables derived using multiple approaches. Literature 1 Nutrient Regions 2 Reference Streams Tri-section 3 25% MEANS Parameter (range) (range) (median) (median) (percentile) (all methods) TN (mg/l) TP (mg/l) turbidity (NTU) NA sestonic chla (ug/l) benthic chla (mg/m2) 2-7 NA Dodds WK, Jones JR, Welch EB (1998) Suggested classification of stream trophic state: Distributions of temperate stream types by chlorophyll, total nitrogen, and phosphorus. Water Res. 32, These values are for streams in the mesotrophic range. 2. From EPA 822-B--17, -18, -19, -2; EPA 822-B-1-13, -14, Tri-section values are for upper one-third streams in US EPA Region 7 having highest total richness for macroinvertebrates

15 Reference sites Macroinvertebrate richness Total Phosphorus (mg/l) Turbidity (NTU) Blue triangle = Reference sites Yellow circle = Nonreference sites

16 Reference Values Number of sites TOTAL NITROGEN USEPA Nutrient Criteria Manual 75% 25% Reference All sites Black = 25th%ile of all sites Red = 75th%ile of Best Professional Judgment sites Blue = median of trisection (chla) sites

17 Analyses Robust regression Downweights outliers Nutrients vs. biological responses Nutrients and biology vs. watershed size LOWESS smoothing curve Nonparametric regression technique LOcally WEighted Scatterplot Smoothing

18 Smoothing Techniques Macroinvertebrate Total Richness Black = Regression Red = LOWESS Smooth Blue = Median Smooth Light blue = Polynomial Mean Total Phosphorus (mg/l)

19 Total Richness TN r 2 =.9 p =. Fish Ratio of Sensitive Species TP r 2 =.2 p = Mean Total Nitrogen (mg/l) Total Richness Turbidity r 2 =.1 p =. Total Richness Size r 2 =.23 p =

20 14 Macroinvertebrates 14 Total Richness TN r 2 =.5 p =.1 Total Richness TP r 2 =.38 p = Mean Total Nitrogen (mg/l) Mean Total Phosphorus (mg/l) 14 Total Richness Turbidity r 2 =.54 p =. Total Richness Size r 2 =. p = Mean Turbidity (NTU)

21 Piecewise Regression Total Richness Mean Total Phosphorus (mg/l)

22 Next Steps Piecewise regression Break point regression Toms and Lesperance, Ecology 23, Piecewise Regression: A Tool for Identifying Ecological Thresholds

23 Next Steps Ratios by ER (richness:tn, etc.). Remove variance caused by turbidity before examining macroinvertebrate richness with nutrients. Precipitation Annual average of each watershed. As a substitute for stream flow.