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New Benthic Macroinvertebrate Health Indicator

New Benthic Macroinvertebrate Health Indicator. Katie Foreman, Claire Buchanan, Andrea Nagel, Scott Phillips, Nontidal Workgroup MASC Indicator Workshop December 17, 2008. Outline. Brief history of 2007 benthic indicator Brief review of 2008 methodology List of issues brought forth by NTWG

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New Benthic Macroinvertebrate Health Indicator

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  1. New Benthic Macroinvertebrate Health Indicator Katie Foreman, Claire Buchanan, Andrea Nagel, Scott Phillips, Nontidal Workgroup MASC Indicator Workshop December 17, 2008

  2. Outline • Brief history of 2007 benthic indicator • Brief review of 2008 methodology • List of issues brought forth by NTWG • Options for mapping and graphing the indicator

  3. History: Watershed indicator development • Fall ’07 – Spring ’08: Watershed Health Indicator developed in response to STAC workshop and report: Developing Environmental Indicators for Assessing the Health of the Chesapeake Bay Watershed • Many options considered and reviewed as an indicator of benthic macroinvertebrate (BMI) health in the Chesapeake Bay Watershed (CBW) through the following process: • NTWG meetings (2007-08) • MASC indicator workshop (Dec. 18-19th, 2007) • IC meeting (Jan. 24th, 2008)

  4. Map of impaired segments chosen as indicator • Final indicator published in CBPO 2007 Health and Restoration Assessment Report: • Map of stream segments with degraded BMI communities in the Bay watershed (from 303(d)/305(b) reports) • Pie chart displaying the % of total stream miles in CBW portion of each state that were impaired, not impaired, and not assessed (2006 reporting period)

  5. 2007 INDICATOR: Chapter 4 Health of Freshwater Streams & Rivers

  6. Benthic Macroinvertebrate Community Health Percent of Non-tidal Tributaries with Healthy Benthic Macroinvertebrate Communities Goal 52% of Goal Achieved Data and Methods: www.chesapeakebay.net/TBD Bar chart of % goal achieved considered, but rejected

  7. Limitations of 2007 indicator • Incomparability between states’ results due to differences in: • sampling methodology, scale, and listing criteria for impaired waters. • These limitations do not allow for an overall watershed-wide assessment of the health of BMI communities.

  8. Organization’s sampling methodologies differ

  9. Improved benthic macroinvertebrate health indicator development • May 7-8th, 2008 MASC Workshop • Consensus that approach by ICPRB (Astin 2006, 2007) to develop a basin-wide BMI indicator would be applied to CBW to improve current indicator.

  10. Advantages of ICPRB basin-wide indicator • Indicator based on original raw data and not assessment/”processed data” • Larger data sets for rigorous metrictesting • Broader geographic distribution • Less unintentional bias in results • More reference sites • Thresholds for “good” and “bad” are more accurate • Consistent scoring across jurisdictional boundaries • Inequalities due to different state assessment methods are minimized Courtesy of ICPRB, 2007

  11. Bay B-IBI ecoregions

  12. Methodology (all ecoregions but coastal plains) • Merge habitat, water quality, and macroinvertebrate data provided by multiple monitoring programs (Access database) • Establish uniform thresholds (“good”/”bad”) to evaluate key habitat parameters common to all programs • Identify reference and degraded habitats in each physiographic region (using habitat and water quality data thresholds) • modified Relative Status Method • Develop standardized scoring for 7 benthic metrics from reference site data • 1-3-5 scoring (thresholds based on 50th, 10th and 90th percentiles of reference community) • Other scoring methods available, but not consistent with Astin 2006 • Sum of scored metrics  multi-metric BIBI • Test sensitivity of biological metrics and index • Discrimination efficiencies; classification efficiencies • Develop BIBI ratings from reference and degraded data distributions • 5 categories: Excellent, Good, Fair, Poor, Very Poor • Validate BIBI by physiographic region • Jackknife procedure Courtesy of ICPRB, 2007

  13. Results: BIBI is efficient • Classification Efficiencies all over 75%, variation between metrics • Jackknife validation: all metrics have acceptable total error (<20%)

  14. Issues to be resolved(from 12/10 NTWG mtg) • The use of the indicator to display stream health compared to state assessment results. • Creating an overall assessment summary of stream health for the entire watershed. • Displaying stream health information on watershed maps.

  15. Next Steps • States review results and identify concerns Jan. 14th conference call • Develop a map of results to supplement indicator Three options: • Sites by average condition rating • Average condition rating by HUC 8/HUC 10 • % Healthy sites (area weighted by HUC 8/HUC 10) • Finalize approach for presenting information on a graph • What is the criteria for “healthy” benthic community, how present this info • Report average condition rating or % of sites that are healthy? • How area weight and “roll-up” the information? • Communicate how indicator is different from states listing of impaired waters • Not comparable to the state’s 303(d) listing process or criteria • Intended as a condition indicator, not regulatory indicator

  16. Map Decisions • Three options: • Point data by average condition rating • Average condition rating • Scale of averaging - HUC 8/HUC 10? • % Healthy sites • What is criteria for “healthy”? • Area weighted by HUC 8/HUC 10?

  17. Map 1: Scores by site

  18. Map 2 and 3: average condition rating by HUC 8 and combo HUC8/10

  19. Map 4 and 5 - % healthy benthic community by HUC 8 and HUC8/10

  20. Recommended: Map 5 • Data is comparable to a restoration goal • Data scored on consistent 1-3-5 scale that is directly comparable to reference sites • More resolution in the data • Bias from localized intense sampled decreased ISSUE: Should a BIBI score of 3 be the threshold?

  21. Indicator graph decisions • What is the criteria for “healthy” benthic community? • BIBI score >3 (used by CBP for estuarine systems) • Report average condition rating or % of sites that are healthy? • How area-weigh and “roll-up” the information? • HUC 8 or combo HUC 8/HUC 10?

  22. Bar Chart 1 and 2 – average vs. % healthy

  23. Recommended: Bar Chart 2, HUC8/HUC10 scales • Data is comparable to a restoration goal • Data scored on consistent 1-3-5 scale that is directly comparable to reference sites • More resolution in the data • Bias from localized intense sampled decreased ISSUE: Should a BIBI score of 3 be the threshold?

  24. References • Astin, L.E. 2006. Data synthesis and bioindicator development for nontidal streams in the interstate Potomac River basin, USA. Ecological Indicators 6: 664-685. • Astin, L. E. 2007. Developing biological indicators from diverse data: The Potomac Basin-wide Index of Benthic Integrity (B-IBI). Ecological Indicators 7: 895-908.

  25. Results Vary by Ecoregion

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