Finalizing the Chesapeake Bay Health Index (BHI) Part 1: Water Quality Index Part 2: Biotic Index

1. Finalizing the Chesapeake Bay Health Index (BHI)Part 1: Water Quality IndexPart 2: Biotic Index Bill Dennison Ben Longstaff, Michael Williams, Claire Buchanan, Roberto Llansó, and Peter Bergstrom On behalf of the Tidal Monitoring and Analysis Workgroup (TMAW) & the Living Resources Analysis Workgroup (LivRAW)

2. Major outcomes • Water Quality Index (Chlorophyll, Dissolved Oxygen, Clarity) will be calculated and mapped, but not necessarily included in calculation of Bay Health Index • Bay Health Index (SAV, BIBI, PIBI) will be calculated, tabulated and used to compare reporting regions • Reporting regions will be altered to group smaller tributaries, more aligned with trib strategies • A 0-100 scale will be used with 5 divisions (stoplight color scheme) • A Bay-wide integration will be calculated from the area-weighted individual indices

3. Strengths of health assessment approach • Rigorous, ecosystem health-related thresholds • Biotic indicators are integrative in nature • SAV (long term) • Benthic IBI (medium term) • Phytoplankton IBI (short term) • Indicators provide assessment of different Chesapeake Bay habitats • Shallow water assessed with SAV • Deep water assessed with Benthic IBI • Open water assessed with Phytoplankton IBI • Mid-channel assessed with water quality • Long term data trends of each indicator available

4. Key communication issues • Provide individual data maps • Express long term data trends of each indicator • Develop new table: sample size (146 x 12-20; 250 x 1; 25 x 12-13); time frame for integration (chl = Mar-Sep; DO = Jun-Sep; Clarity = Mar-Nov); range of values, etc. • Develop ways to calculate and express variability • Use conceptual diagrams to link indicators and various key living resources & habitats

5. Index categories

6. Conceptual diagram

7. Indicators selection • Proposed indicators for 2006 report

8. Water quality maps

9. Water Quality Index 2002 – low flow year Water Quality Index 2003 – high flow year

10. Biotic indices maps

11. Future indicator development • Chemical contaminants • Human health threshold (not water quality) • Tissue samples (integrate over time) • Do not respond annually • Uncertain geographic representation • Confusion with EPA Coastal Condition vs. 303(d) listing • Nutrients • Trend data has linear and non-linear trends • Criteria definition needs to be elucidated • Other examples of separating nutrient concentrations from symptom expressions (e.g., National Estuarine Eutrophication Assessment) • Nutrient limitation approach (Fisher et al.) and nutrient concentration approach could be used • PIBI and Chl are good integrators of nutrients • Nutrients are ‘flashy’ vs. more integrative measures

12. Reporting regions

13. Reporting regions issues • Use detailed maps of depth contours, residence time • Indicate stations on data maps • Provide station by station data (e.g., pdf) • Develop a hyperlinked data set (2007) • Work toward developing mapping approaches and continuous data distributions so that reporting regions are less important

14. Revised reporting regions • Upper Bay • Mid Bay • Lower Bay • Patapsco-Back • Patuxent • Potomac • Rappannock • York • James • Elizabeth • Tangier • Choptank • Chester • Lower Eastern shore • Upper Eastern shore • Upper Western shore • Lower Western shore

15. Benchmark approach issues • Investigate different methods of establishing benchmarks • Percentiles (cumulative frequency distributions) • Link benchmarks to living resources (e.g., DO from BIBI; Clarity from SAV) • Model results • Compare different thresholds (table)

16. Chesapeake Bay health assessment

17. Biotic indices: Bay grasses, Benthic Index of Biotic Integrity, Phytoplankton Index of Biotic Integrity

18. Next steps • Link spatially explicit bay health index with Bay Health & Restoration Assessment • Continue to build technical supporting documentation • Mock up communication product(s) using alternative approaches • Engage communication specialists, IC, STAC and other reviewers and incorporate feedback

19. Retrospective analysis of biotic indicators

20. Example cumulative frequency distribution

25. Indicators selection • Current indicators • Not all indicators can be included at this stage because: • Some are still being developed (tidal wetlands and menhaden) • Timeframe not suitable (chemical contaminants) • Goals and assessment at bay-wide scale (striped bass, blue crab, oysters) • Indicator is for a specific location only (shad)

26. Reporting regions • Discrete regions of the Bay used for purpose of reporting • Not too many in number (currently 14) • Must contain sufficient number of sampling stations for analysis • Based on current CBP segmentation • Group like water bodies • Align, where possible with tributary strategy boundaries, other strata (e.g., B-IBI)

27. Methods: Biotic Index • Aquatic grasses (SAV) • Michael Williams (CBP/UMCES) • Benthic Index of Biotic Integrity (B-IBI) • Roberto Llansó (Versar) • Phytoplankton Index of Biotic Integrity (P-IBI) • Claire Buchanan (ICPRB) • Biotic and Bay health index • Michael Williams (CBP/UMCES)

28. Aquatic grasses: goals • Restoration goals for each Chesapeake Bay segment (Use Attainability Analysis) • All segment goals within a reporting region combined  reporting region goal (ha)

29. Aquatic grasses: compliance assessment • Most recent year data • Compliance of a reporting region • Total area present (acres) as a proportion of the total restoration goal • If SAV acreages exceed the restoration acreages, that segment’s SAV was reduced to equal the restoration acreage (i.e., can only = 100% or less)

30. Benthic-IBI: data • Chesapeake Bay Benthic Monitoring Program data • Collected August through September • Approximately 250 stratified random sampling stations Location of Benthic monitoring probability-based sites in 2005

31. Benthic-IBI: goals • Chesapeake Bay Monitoring Programs have adopted Benthic Community Restoration Goals as a monitoring tool • The restoration goals are quantitative benchmarks: They describe the characteristics of benthic assemblages expected in non-degraded habitats • The B-IBI is scaled from 1 to 5, and sites with values of 3.0 or more are considered to meet the Restoration Goals.

32. Benthic-IBI: compliance assessment • Multi-metric, habitat-specific index of benthic community condition • Selection of metrics and the values for scoring metrics developed separately for each of seven benthic habitat types in Chesapeake Bay • Described in: • Weisberg et al. (1997), Estuaries 20:149-158 • Alden et al. (2002), Environmetrics 13:473-498

33. Benthic Index of Biotic Integrity Metric Scoring System

34. Excess Abundance or Excess Biomass Indicative of Stress

35. Metrics

36. Benthic-IBI: compliance assessment • Estimate the amount of area in a reporting region that meets the Restoration Goals (B-IBI >=3.0) • Every site that meets the goal assigned a value of 1, otherwise a site is assigned 0 • Proportion of area meeting the goals and its variance is estimated • For some reporting regions, estimates were calculated for subregions and these were then combined using proportion of area as weighting factor.

37. Phytoplankton: Data • VA and MD Phytoplankton Monitoring Survey Data • Approximately 25 stations • Collected 12-13 times a year • Spring (March, April, May) • Summer (July, August, September)

38. Phytoplankton IBI - Goal • PIBI interim goal of 4.0 (1.0 - 5.0 scale) • high level of biological integrity is certain • very low risk of harmful algal blooms • assoc. WQ meets SAV habitat requirements • commensurate with Ches Bay water clarity and DO criteria attainment • Not establish how attainment of a PIBI goal of 4.0 should be measured (mean? median? threshold? 10th%?)

39. Application of BIBI method to PIBI

40. Application of BIBI method to PIBI

41. Findings • Pass/fail method currently used to report BIBI status can also be successfully applied to PIBI • Goal of “100% PIBI > 3.0 threshold criterion” is in general agreement with goal of “median or mean PIBI = 4.0” • “% of Goal” method used to report the 3 biotic and 3 water quality indicators differs from “% attainment of water quality criteria” methods

42. Recommendations • Align methods and goals to that used for the Benthic IBI • % achievement of the threshold criteria • Threshold criteria defined as median PIBI of 3 • Area weighted

43. Phytoplankton-IBI: compliance assessment

44. Phytoplankton-IBI: compliance assessment

45. Biotic Index

46. 2002 Bay Health Index

47. 2003 Bay Health Index

48. Question to address: Do we agree with the proposed approach for assessing compliance for each of the three indicators (Aquatic grass, BIBI, PIBI)? • Data sources? • Goals and thresholds? • Compliance assessment methods? Do we agree that Biotic index is determined as the average of the 3 compliance estimates

49. Question to address: • Do we agree that Bay health index is determined as the average of the 2 component indices (Water quality index & Biotic index)? • What are the appropriate groupings for the BHI values: Those proposed? Another? • How might the index be improved in the future…

50. Phytoplankton-IBI: compliance assessment