Ben Jessup – Tetra Tech, Inc.

1. BENTHIC INDICATORS FOR THESUBSTANTIALLY ALTERED LANDSCAPE OF THEMISSISSIPPI ALLUVIAL PLAINS Ben Jessup – Tetra Tech, Inc. Valerie Alley – Mississippi DEQ Matt Hicks – USGS SWPBA November 14, 2012 Lake Guntersville State Park

2. Sampling Locations

6. Analytical Steps • Gather and Compile Data • Define the Disturbance Gradient • Classify Sites by Natural Types • Assess Metric Responses to Disturbance • Combine Metrics in an Index

7. Step 1: Gather Data

8. Data Elements • Collected during 2002*, 2007, 2008, and 2010 by MDEQ and the U.S.G.S. • Macroinvertebrates, water quality, habitat ratings, general site observations, and GIS. • 57 sites (2002 samples eliminated) • QC process for lab processes • In EDAS for metric calculation

9. Step 2: Define the Disturbance Gradient (preliminary) LD: Score +1 for each MD: score (-1) for each

10. Disturbance Gradient Longitude Latitude Bluff Inter. -5 -4 -3 -2 -1 0 1 2 3 4 5 Disturbance Gradient Score Map

11. NMS Ordination Core Bluff

12. Natural Gradient % Alluvium Flow Rate

13. Step 3: Site Classification • All the “best” sites (lower disturbance) have bluff and non-Delta land in their catchments • Core Delta sites are essentially different than bluff sites (slope, substrate, flow, soils, etc.) • This confounds the “natural” and “anthropogenic” gradients • We should not expect bluff-like bug samples in the core of the Delta • Two site classes: Bluff Hills and Core Delta

14. Redefine the Disturbance Gradient

15. Step 4: Metric Responses • Screened metrics against the disturbance gradient score using correlation • Plotted the most responsive metrics to evaluate responses within site classes • Compared reference and stressed within site classes using DE and Z-score

16. Bluff Sites Interior Sites Disturbance Gradient Score

17. Metric Response among Classes EPT Taxa LD Other MD Ref MD Other Bluff Hills Interior Delta

18. Bluff Sites Interior Sites Disturbance Gradient Score

19. Bluff Sites Interior Sites Disturbance Gradient Score

20. Metric Results • In the Interior Delta • Only five of 67 potential metrics had DE ≥69% • In the Bluff Hills • One metric in each category had a DE = 100% • Scoring was based on the 5th and 95th %iles

21. Combine Metrics in an Index Interior Delta • Of several combinations of responsive metrics • The best index had a DE of 92% a ”X” in the formula represents the metric value • b POET includes Plecoptera, Odonata, Ephemeroptera, & Trichoptera

22. Combine Metrics in an Index Bluff Hills • Several combinations of responsive metrics • The best index had a DE of 100% 1”X” in the formula represents the metric value

23. Index Performance Bluff Hills Drainage Interior Delta • DE: 100% • Ref 25th: 75 • 90% CI: ±6.2 • DE: 92% • Ref 25th: 43 • 90% CI: ±14.9

24. Biological Condition Gradient LD MD MD LD Bluff Hills Interior Delta (?) Observable Delta Sites

25. Conclusions • Metrics responses are related to both the stressor gradient and site classes • In this case it is best to find metrics that respond uniquely in each site class • Stressor gradients have different meanings in different site classes

26. “I’m afraid you have humans”