1. Periphyton Data from National-Scale Assessments Can Inform Nutrient Criteria Development for Southeastern States R. Jan Stevenson Michigan State University East Lansing, MI 48824

2. 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

3. 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

4. Streams sampled in Region 4 during summer 2006 and summer 2007 (SPNBR and SPNR) N=169

5. Wide range of nutrient concentrations should be sufficient to produce biological responses The 25 th percentiles of TP and TN at all sites sampled in Region 4 streams were 0.020 and 0.234 mg/L, respectively

6. pH was unusually low in Coastal Plain Streams Region 4 NRSA

7. Correlation Between Water Chemistry and Land Use Land Cover Variables

8. Diatom Species Composition Highly Related to Nutrient & pH/Cond Gradients

9. Region 4 TP Metric (Weighted Average (PLS) Regression) ∑p i Opt i – i=1-n spp Observed TP (ln(mg TP/L)) Inferred TP (ln(mg TP/L)) Inferred TP Jack (ln(mg TP/L)) Resid Inf TP (ln(mg TP/L)) Resid Inf TP Jack (ln(mg TP/L)) C D A B

10. Many Diatom Metrics Correlated to TP and Human Disturbance Gradient

11. Most Response is in Low Range of Nutrients Note Linearity and Non-linearity of Responses

12. Weighted Average Metric Better Related to Land Use than Indicator Species Metrics

13. Response of Periphyton Could Be Used to Justify Nutrient Criteria (thresholds or reference condition)

14. NAWQA-NEET

16. NARS: Periphyton MMI (no new metrics used) Site Class (R=reference, MD=moderately disturbed, HD=highly disturbed, V=reference validation)

17. Metrics Selected for National and Regional MMIs

18. NRSA Periphyton MMI by Ecoregion: Eastern Highlands and Lowland Plains Site Class (R=ref, MD=mod dist, HD=high dist, V= validation) Traditional MMIModeled MMI

19. NRSA: Species Traits

20. 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

21. 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 (∑p i Opt i ) – Indicator species metrics (% spp or ind w trait)

22. 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