Lower Trophic Level Indices of Biological Integrity and Their Possible CBP Uses

1. Lower Trophic Level Indices of Biological Integrity and Their Possible CBP Uses Presentation to the Monitoring and Assessment Subcommittee May 12, 2004 Meeting by Claire Buchanan and Jacqueline Johnson Interstate Commission on the Potomac River Basin

2. “Lower Trophic Levels” Phytoplankton SAV Zooplankton Benthos

3. Source Water Quality Lower Trophic Levels Resource Source to Resource

4. Biological Integrity • “the capability of supporting and maintaining a balanced, integrated, adaptive community of organisms having a species composition, diversity, and functional organization comparable to that of the natural (minimally impaired) habitat...” (Karr and Dudley 1981) • Healthy biological communities are: • more resilient to natural and man-made disruptions • require minimal external support from management

5. Index Development Steps • Assess Habitat • Select Metrics • Score Metrics • Score Index • Validate Index

6. SAV • Restoration Goals • Not an IBI • May be used like an IBI • “Reference sites” derived from historic data • Poor water clarity is major stressor

8. Benthos Restoration Goals Led to B-IBI • Reference Site Criteria • No highly developed watersheds, no known point source discharges, and no toxic pollutants • Low total organic content in sediments • Bottom dissolved oxygen All records >2 mg DO liter-1 90% records >3 mg DO liter-1 80% records >5 mg DO liter-1

9. —5 meets goal — 3 — 1 — 2.7 — 2.1 marginal degraded severely degraded Benthic IBIs • strongly reflect seasonal habitat conditions • communities “meeting goal”: • high abundance and high diversity of taxa • pollution sensitive species dominate • diverse feeding guilds • IBI Classification Efficiencies (Summer) IBI Scale

11. Phytoplankton • Reference Criteria for Samples in All Seasons • Low phosphorus (PO4) and • Low nitrogen (DIN) and • Relatively high light (Secchi depth)

12. IBI Scale 5 — 4 3 2 1 — good fair-good fair fair-poor poor - - - - Phytoplankton IBIs • strongly reflect immediate water quality conditions • reference, or “good,” communities: • no nuisance algal blooms • associated with high DO and good water clarity • often higher median biomass (consistent good supply) • IBI Classification Efficiencies

14. Zooplankton • POLYHALINE Reference Criteria for Summer Samples • Low phosphorus (PO4) and • Low nitrogen (DIN) and • Relatively high light (Secchi depth) Same as phytoplankton

15. * * * Zooplankton MESOHALINE Reference Criteria for Summer Samples • Phytoplankton reference habitat criteria aren’t very effective…

16. low DIN and • low PO4and • low chlorophyll aand • high diatom biomass and • low dinoflagellate biomass (CART analysis)

17. IBI Scale 5 — 4 3 2 1 — good fair-good fair fair-poor poor - - - - Zooplankton • reflect water quality and algal food conditions • reference, or “good,” communities: • higher median abundance & biomass, esp. copepods • more “blooms” (desirable for fish) • greater diversity (more robust) • IBI Classification Efficiencies

19. Upper Bay Choptank Patuxent Potomac Rappahannock York James Food Availability Index Anadromous Fish Spawning & Nursery Areas (Mesozooplankton liter-1) Optimal: > 25 / liter Minimum: 15 to 25 / liter Below Minimum: 5 to 15 / liter Poor: < 5 / liter

21. Analysis Tools at Hand • SAV Restoration Goals • Benthic Restoration Goals and IBI • Phytoplankton IBI • Zooplankton IBI, FAI, Habitat Index

22. 1. Confirm Achievement of Designated Uses DO, water clarity, and chlorophyll a criteria are protective of designated uses Criteria attainment doesn’t guarantee achievement of designated uses

23. Designated Uses

24. Dry Years Wet Years Water Clarity Criteria Attainment 0% 100% Ex. Potomac Shallow Water Habitats SAV Goal

25. Ex. Potomac Deep Water Habitats 3.6 2.1 2.4 3.0 2.1 2.6 1.9 2.4 - - 3.3 1.6 2.2 1.3 Dry Years Wet Years Dissolved Oxygen Criteria Attainment 60% 100% Benthic IBI

26. 1.8 2.2 2.8 2.0 1.9 2.4 Dry Years Wet Years Risk of Algal Blooms 100% 0% Ex. Potomac Open Water Habitats Phytoplankton IBI

27. 2. Components in Index of Ecosystem Integrity (IEI) • Ecological Integrity • “sum of balanced, integrated, and adaptive chemical, physical, and biological data can be equated with ecological integrity” (Karr and Dudley 1981)

28. Jordan and Vaas 2000 “An Index of ecosystem integrity for Northern Chesapeake Bay” Environmental Science and Policy 3:S59-S88 • DIN • PO4 • Secchi depth • Chlorophyll a • Bluegreen and dinoflagellate biomasses • Ratio of mesozooplankton to microzooplankton • Microzooplankton biomass • Benthic restoration goal values (pre-IBI index) • % DO observations <1 ppm in bottom waters or <5ppm above pycnocline • % SAV Tier 1 goal achieved • Index of relative proportions of carnivores, planktivores and benthivores for fish • Number of species in bottom trawl

29. 3D Water Quality Model EcoPath/EcoSim Model Watershed Model Model elements Phytoplankton in common: SAV Benthos Zooplankton Oysters Source Water Quality Lower Trophic Levels Resource 3. Mechanism for Coupling WQ & Fisheries Models

30. 4. Fisheries Ecosystem Planning • Habitat, Habitat Requirements and Habitat Management (Element 3) • Assess habitat value using habitat requirements • Produce habitat suitability maps • Indicators of Ecosystem Health and Biological Reference Points (Element 6) • Use data from long-term monitoring data sets • Evaluate usefulness of existing indicators • Develop a framework in which to use indicators

31. Summary of Possible CBP Uses • Confirm Achievement of Designated Uses • Develop Index of Ecosystem Health • Provide a Mechanism to Couple WQ and Fisheries Models • Fisheries Ecosystem Planning

32. Data Time Line

33. Acknowledgements the CBP monitoring programs, past and present Supported by Interstate Commission on the Potomac River Basin & EPA Chesapeake Bay Program