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 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 25 th percentiles of TP and TN at all sites sampled in Region 4 streams were and 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

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

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)

NAWQA-NEET

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

Metrics Selected for National and Regional MMIs

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

NRSA: Species Traits

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 (∑p i Opt i ) – 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