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Periphyton Data from National-Scale Assessments Can Inform Nutrient Criteria Development for Southeastern States. R. Jan Stevenson Michigan State University East Lansing, MI 48824.
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Periphyton Data from National-Scale Assessments Can Inform Nutrient Criteria Development for Southeastern States R. Jan Stevenson Michigan State University East Lansing, MI 48824
Periphyton Data from Region 4 and National-Scale Assessments Can Inform Nutrient Criteria Development for Southeastern States R. Jan Stevenson Michigan State University East Lansing, MI 48824 Chris Decker U.S. Environmental Protection Agency, Region 4 Athens, GA 30605
Outline • Review “Diatom Responses to Nutrient Conditions in Region 4 Streams”, a report prepared for USEPA Region 4 by Chris Decker and me. • Review results from NAWQA-NEET and NRSA periphyton studies that relate to Region 4 • NEET: Covariation in pH and NP with Human Disturbance Gradient confounds assessing nutrient effect • NRSA: Modeled MMIs with tested metrics, species characterizations for refined metric testing • Next steps • Further species traits analysis • Website and Database
Streams sampled in Region 4 during summer 2006 and summer 2007 (SPNBR and SPNR) N=169
Wide range of nutrient concentrations should be sufficient to produce biological responses The 25th percentiles of TP and TN at all sites sampled in Region 4 streams were 0.020 and 0.234 mg/L, respectively
pH was unusually low in Coastal Plain Streams Region 4 NRSA
Correlation Between Water Chemistry and Land Use Land Cover Variables
Diatom Species Composition Highly Related to Nutrient & pH/Cond Gradients
C D Inferred TP Jack (ln(mg TP/L)) Resid Inf TP Jack (ln(mg TP/L)) Observed TP (ln(mg TP/L)) Observed TP (ln(mg TP/L)) A B Inferred TP (ln(mg TP/L)) Resid Inf TP (ln(mg TP/L)) Observed TP (ln(mg TP/L)) Observed TP (ln(mg TP/L)) Region 4 TP Metric (Weighted Average (PLS) Regression) • ∑piOpti • i=1-n spp
Many Diatom Metrics Correlated to TP and Human Disturbance Gradient
Most Response is in Low Range of Nutrients Note Linearity and Non-linearity of Responses
Weighted Average Metric Better Related to Land Use than Indicator Species Metrics
Response of Periphyton Could Be Used to Justify Nutrient Criteria (thresholds or reference condition)
NARS: Periphyton MMI(no new metrics used) Site Class (R=reference, MD=moderately disturbed, HD=highly disturbed, V=reference validation)
Traditional MMI Modeled MMI NRSA Periphyton MMI by Ecoregion:Eastern Highlandsand Lowland Plains Site Class (R=ref, MD=mod dist, HD=high dist, V= validation)
Web Site: Species Traits • Trait Types • Weighted Average Optima • Indicator Species Values • Indicate What? • Reference and Trashed or Human Disturbance Gradient • Biological condition traits • Sensitive and Tolerant Taxa • Ecological Functions • Stressors • Nutrients, pH, siltation, hydrologic alteration (dam upstream) • Existing and New Traits based on NARS surveys
Web Site: Database • Input Tables • Species names and traits (12 traits at a time) • Sample IDs, species names, counts • Taxa harmonization table • QA • Matches for all taxa names, count totals • Metric calculation • Weighted average metrics (∑piOpti) • Indicator species metrics (% spp or ind w trait)
Summary • Periphyton metrics work in Region 4 and can be use to support development of nutrient criteria • Periphyton metrics could be better • Lots of Potential from Existing and New Data Sets • Next steps • Further species traits analysis • Website and Database