Bottom Habitat

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Chesapeake Bay Program Indicator Framework

Reporting Level Indicators

Indicator and Data Survey

LONG-TERM BENTHIC (LTB) MONITORING PROGRAM 

For each indicator for which you are responsible, please provide the following information.  This information will be made available to the developers of the reports, the reviewers of the reports and by members of the public who may request detailed information about the data used in the reports.  Please refer to the sample for examples of the level of detail that should be provided.

(PLEASE NOTE:  For indicators that do not have data (narrative info only for the March 2006 reports), complete as much of the survey as possible.  If possible, indicate plans for the development of data to be featured in the 2007 Reports.)

A.  Category/Name/Source/Contact

(1) Category of Indicator

___ Factors Impacting Bay and Watershed Health

___ Restoration and Protection Efforts

___ Watershed Health

_X_ Bay Health

(2) Name of Indicator:  Bottom Habitat (Benthic Index of Biotic Integrity)

(3) Description of Data set used to calculate percent goal:  Percent area of Chesapeake Bay and 10 sampling strata failing the Chesapeake benthic community restoration goals in 2009. 

For what purpose(s) were the data collected? (e.g., tracking, research, or long-term monitoring.)  All of the above.

Which parameters were measured directly?  Abundance, biomass, and species composition of macrobenthos (i.e., those benthic organisms retained on a 0.5-mm mesh sieve).

Which were obtained by calculation?  Benthic Index of Biotic Integrity (B-IBI) and component metrics.

(4) Source(s) of Data:  Versar, Inc., under contract with the Maryland department of Natural Resources (MDNR); and Old Dominion University, under contract with the Virginia department of Environmental Quality (VA DEQ).

Is the complete data set accessible, including metadata, data-dictionaries and embedded definitions?  If yes, please indicate where complete dataset can be obtained.  Yes.  The data sets for Maryland, Data Dictionary, and the Quality Assurance Project Plan can be found at:http://www.baybenthos.versar.com/data.htm.  The complete data sets for 2009 will be available at this website by May 15, 2010.  The Chesapeake Benthic Monitoring Homepage (www.baybenthos.versar.com) describes the methods and presents the results of the LTB program, including reports, documents, and presentations.  The Virginia Monitoring Program results are also presented at this website.  The Virginia data sets can be obtained from Dr. Daniel Dauer (ODU), telephone: 757-683-4709.  Archived data can be obtained from the Data Hub served by the Chesapeake Information Management System (CIMS): http://www.chesapeakebay.net/cims/

(5) Custodian of Source Data (and Indicator, if different):  Dr. Roberto J. Llansó, Versar Inc., Columbia, MD.;  Dr. Daniel M. Dauer, Department of Biological Sciences, Old Dominion University, Norfolk, VA.  

(6) CBPO Contact:  Jacqueline Johnson, Chesapeake Bay Program, Annapolis, MD.

B.  Communication Questions

(complete either part 1, 2, or 3)

1.  Restoration and Protection Efforts indicators only

(7a) How much has been completed since 1985 (or baseline year)?  How much has been completed since 2000?

(8a) How much was done last year?

(9a) What is the current status in relation to a goal?

(10a) What is the key story told by this indicator?

(11a) Why is it important to report this information?

(12a) What detail and/or diagnostic indicators are related to this reporting level indicator? (Detail and diagnostic indicators can be spatially-specific, parameter-specific, temporally-specific information, etc.)

2.  Bay Health or Watershed Health indicators only

(7b) What is the long-term trend?  (since start of data collection)

1996-2009 Baywide.  No statistical trends are currently run on the random data.  However, no trend of increase or decrease is discernible by inspection of the data. Between 1996 and 2009, this indicator has averaged 47% and has ranged from 40.8% 56.1% (Figure 1).  

(8b) What is the short-term trend? (10-year trend)

See answer 7b above

Figure 1. Bay-wide BIBI

BottomHabitatFigure1 (1).gif

(9b) What is the current status in relation to a goal?

In 2009, a new high of 56.1% of the Chesapeake Bay tidal waters achieved the benthic community restoration goals. Baywide, goal achievement increased 14.6 percent, from 41.5 percent to 56.1 percent. 

•The mainstem bay areas improved, on average, 15 percent from 2008:

o32 percent increase in the upper-Bay mainstem 

o28 percent decrease in mid-Bay mainstem 

o40 percent increase in lower-Bay mainstem  

•Most of the Bay’s major tributaries improved, on average, 15 percent from 2008:

o17 percent increase in the Choptank

o17 percent increase in the Patapsco

o12 percent increase in the Patuxent

o3 percent increase in the Potomac

o19 percent increase in the Upper Eastern Shore tributaries, Maryland

o15 percent decrease in the Upper Western Shore tributaries, Maryland

o12 percent decrease in the Lower Eastern Shore tributaries, Virginia

o16.5 percent increase in the Lower Western Shore tributaries, Virginia

o3 percent increase in the Rappahannock

o15 percent increase in the York

oNo change in the Elizabeth

The Potomac River was largely unchanged from 2008, again the result of sampling artifact due to fewer random sites in its lower portion.  The lower portion of the Potomac is usually azoic.  

(10b) What does this indicator tell us?

Benthic macroinvertebrates are sensitive and reliable indicators of habitat quality in aquatic environments.  This is because most benthic organisms have limited mobility and cannot avoid changes in environmental conditions.  Benthic organisms live in bottom sediments where exposure to contaminants and oxygen stress is most frequent.  The benthos includes diverse taxa representing a variety of sizes, modes of reproduction, feeding guilds, life history characteristics, and physiological tolerances to environmental conditions.  Therefore, they respond to and integrate natural and anthropogenic changes in environmental conditions in a variety of ways.

Figure 2. Maryland Tributaries

BottomHabitatFigure2 (2).gif

Figure 3. Virginia Tributaries

BottomHabitatFigure3 (1).gif

(11b) Why is it important to report this information?

Benthic organisms are sensitive to changes in water quality.  Benthic organisms are also important secondary producers.  Benthic secondary production constitutes the base that leads to most fisheries species.  In Chesapeake Bay, a majority of fish feed on benthos.  Thus the condition of the benthic community provides an indication of the overall health and productivity of the Bay, and a direct measure of the effectiveness of management actions.

(12b) What detail and/or diagnostic indicators are related to this reporting level indicator?

3.  Factors Impacting Bay and Watershed Health indicators only

(7c) What is the long-term trend?  (since start of data collection)

(8c) What is the short-term trend? (3 to 5 year trend)

(9c) What is the current status?

(10c) What is the key story told by this indicator?

(11c) Why is it important to report this information?

(12c) What detail and/or diagnostic indicators are related to this reporting level indicator?

C.  Temporal Considerations

(13) Data Collection Date(s):  Random element – Maryland, 1994-2009; Virginia, 1996-2009.  Long-term fixed sites – 1985-2009. 

(14) Planned Update Frequency (e.g. - annual, bi-annual):

(a) Source Data: Annual

(b) Indicator: Annual

(15) For annual reporting, month spatial data is available for reporting:  May 15 of the following year for Maryland; June 15 for Virginia; but we are working to be able to provide random sampling results by mid to late February every year.

D.  Spatial Considerations

(16) Type of Geography of Source Data (point, line polygon, other):  Point data, with samples allocated according to a stratified simple random design, which allows us to estimate areal extent of conditions in Chesapeake Bay.

(17) Acceptable Level of Spatial Aggregation (e.g. - county, state, major basin, tributary basin, HUC):  Annually, twenty-five samples are allocated randomly to each of ten strata, and the data are aggregated by stratum, the Maryland Bay, the Virginia Bay, and the Chesapeake Bay.  The ten strata are: each of the major western shore tributaries (Patuxent, Potomac, Rappahannock, York, and James rivers), the Maryland upper western shore tributaries, the Maryland eastern shore tributaries, the Maryland upper Bay mainstem, and the middle (Maryland) and lower (Virginia) Bay mainstems.  The data are also aggregated by Chesapeake Bay Program segment to contribute information to the Water Quality Characterization report (305b report) and list of impaired waters (303d list).

(18) Are there geographic areas with missing data?  If so, where?  All the tidal waters of the Chesapeake Bay deeper than 1 m MLLW have a probability of being sampled.  Regions of the Maryland mainstem deeper than 12 m are not including in the sampling strata because these areas are subjected to summer anoxia and have consistently been found to be azoic.  The area of the deep mainstem, however, is included in the estimates of condition for the Middle Bay stratum, the Maryland Bay, and the Chesapeake Bay.  

(19) The spatial extent of this indicator best described as:

(a) Chesapeake Bay (estuary) X

(b) Chesapeake Bay Watershed

(c) Other (please describe): _______________________

Please submit any appropriate examples of how this information has been mapped or otherwise portrayed geographically in the past.

Please refer to: www.baybenthos.versar.com, and see “How’s the Bay Doing?”

Also see http://www.baybenthos.versar.com/referenc.htm, for GIS applications of the B-IBI in the Annual Report and Special Topic reports (Impairment Decision Process, Addendum to Development of Diagnostic Approaches).  Further examples of GIS applications can be found in:  

•Llansó R.J. et al.  2003.  Application of the benthic index of biotic integrity to environmental monitoring in Chesapeake Bay.  Environmental Monitoring and Assessment 81:163-174.

• Dauer D.M. and R.J. Llansó.  2003.  Spatial scales and probability based sampling in determining levels of benthic community degradation in the Chesapeake Bay. Environmental Monitoring and Assessment 81:175-186.

(20) Can appropriate diagnostic indicators be represented geographically?

Yes.  Please see above.

E.  Data Analysis and Interpretation

(Please provide appropriate references and location of documentation if hard to find.)

(21) Is the conceptual model used to transform these measurements into an indicator widely accepted as a scientifically sound representation of the phenomenon it indicates?  (i.e., how well do the data represent the phenomenon?) 

Yes.  The benthic index of biotic integrity method has been applied widely in freshwater and estuarine systems.  The Chesapeake Bay B-IBI has undergone extensive technical review and peer review.  Baywide estimates are dependent on fully validated thresholds for assessing benthic community condition in Chesapeake Bay.  The thresholds and index were validated by Weisberg et al. (1997):

•Weisberg, S.B., J.A. Ranasinghe, D.M. Dauer, L.C. Schaffner, R.J. Diaz, and J.B. Frithsen.  1997.  An estuarine benthic index of biotic integrity (B-IBI) for Chesapeake Bay.  Estuaries 20:149-158.

The B-IBI and the stratified random sampling design allow a validated, unambiguous approach to characterizing conditions in the Chesapeake Bay.  The Chesapeake Bay B-IBI was shown by Alden et al. (2002) to be sensitive, stable, robust, and statistically sound:

•Alden, R.W. III, D.M. Dauer, J. A. Ranasinghe, L.C. Scott, and R.J. Llansó.  2002.  Statistical verification of the Chesapeake Bay Benthic Index of Biotic Integrity.  Environmetrics 13:473-498.

The Chesapeake Bay B-IBI is applicable to a wide range of habitats, from tidal freshwater mud to polyhaline sand in the Chesapeake Bay.  This is an important and useful feature of the index because it allows characterization of local gradients of pollution and conditions across habitats.  A study to develop diagnostic tools based on the B-IBI that differentiate between low dissolved oxygen impacts on benthos and those from toxic contamination was recently conducted by Dauer et al. (2002) and further augmented the usefulness of the B-IBI to management.  Please refer to:

•Dauer, D.M., M.F. Lane, and R.J. Llansó.  2002.  Development of diagnostic approaches to determine sources of anthropogenic stress affecting benthic community condition in the Chesapeake Bay.  Prepared for U.S. Environmental Protection Agency, Chesapeake Bay Program Office, by Department of Biological Sciences, Old Dominion University, Norfolk, VA. http://www.baybenthos.versar.com/Doc...Apprch_Rpt.pdf

http://www.baybenthos.versar.com/Doc...Apprch_Add.pdf

The Chesapeake Bay B-IBI has also been used to examine associations between macrobenthic communities, measures of pollution of the water column and sediment, and measures of anthropogenic activities throughout the watershed.  Three major associations were identified: (1) benthic community condition was strongly correlated with low dissolved oxygen events; (2) benthic community condition was negatively related to sediment contamination; and (3) residual variation was correlated with surrogates for eutrophication: water column concentrations of total nitrogen, total phosphorus, and chlorophyll a.  In addition, associations between benthic condition and anthropogenic inputs and activities in the watershed were also identified.  Benthic community condition was negatively correlated with measures of urbanization and positively correlated with watershed forestation.  Please see:

•Dauer, D.M., J.A. Ranasinghe, and S.B. Weisberg.  2000.  Relationships between benthic community condition, water quality, sediment quality, nutrient loads, and land use patterns in Chesapeake Bay.  Estuaries 23:80-96.

Relationships between patterns of habitat quality and benthic biotic integrity as measured by the B-IBI were also examined.  An independent measure of habitat quality was obtained using the SPI (Sediment Profile Imaging) approach, in which a specially designed camera system penetrates the sediment and creates an image that is assessed for habitat quality.  Benthic habitat quality is assessed by calculation of the Organism-Sediment Index (OSI).  A strong positive relationship was found supporting the hypothesis that when habitat quality deteriorates biotic integrity degrades, and when habitat quality is restored biotic integrity improves.  Please see:

•Diaz, R.J., G.R. Cutter, Jr., and D.M. Dauer.  2003.  A comparison of two methods for estimating the status of benthic habitat quality in the Virginia Chesapeake Bay.  Journal of Experimental Marine Biology and Ecology 285-286:371-381.

Finally, the Chesapeake Bay B-IBI has been successfully used to develop biological criteria for evaluating estuarine waters for reporting overall condition and identification of impaired waters under the Clean Water Act.  Please refer to:

•Llansó, R.J., J.H. Vølstad, D.M. Dauer, and M.F. Lane  2005.  2006 303(d) Assessment Methods for Chesapeake Bay Benthos. Final Report to the Virginia Department of Environmental Quality. 32 pp. plus appendices.  http://www.baybenthos.versar.com/Doc...ecProc_Alt.pdf

(22) What is the process by which the raw data is summarized for development and presentation of the indicator?

Please refer to: http://www.baybenthos.versar.com/docs/ChesBayBIBI.PDF

(23) Are any tools required to generate the indicator data (e.g. - Interpolator, watershed model)

No, other than the methods for calculating the B-IBI, see above.

(24) Are the computations widely accepted as scientifically sound?

Yes.  Please refer to: 

•Alden, R.W. III, D.M. Dauer, J. A. Ranasinghe, L.C. Scott, and R.J. Llansó.  2002.  Statistical verification of the Chesapeake Bay Benthic Index of Biotic Integrity.  Environmetrics 13:473-498.

(25) Have appropriate statistical methods been used to generalize or portray data beyond the time or spatial locations where measurements were made (e.g., statistical survey inference, no generalization is possible)? 

Yes.  The B-IBI and the stratified random sampling design allow inference of areal condition with known precision.  The data are aggregated to the stratum and baywide levels.  For details on the statistical methods, see the Methods Section of the Annual Report.  The Annual Report can be found at:

http://www.baybenthos.versar.com/referenc.htm

(26) Are there established reference points, thresholds or ranges of values for this indicator that unambiguously reflect the desired state of the environment? (health/stressors only)

Yes.  Thresholds or Benthic Community Restoration Goals were established by Ranasinghe et al. (1994), and updated and validated by Weisberg et al (1997):

•Ranasinghe, J.A., S.B. Weisberg, D.M. Dauer, L.C. Schaffner, R.J. Diaz, and J.B. Frithsen.  1994.  Chesapeake Bay Benthic Community Restoration Goals.  Prepared for the U.S. Environmental Protection Agency, Chesapeake Bay Office, and the Maryland Department of Natural Resources by Versar, Inc.  Chesapeake Bay Program Report No. CBP/TRS 107/94. 49 pp. plus appendices.

•Weisberg, S.B., J.A. Ranasinghe, D.M. Dauer, L.C. Schaffner, R.J. Diaz, and J.B. Frithsen.  1997.  An estuarine benthic index of biotic integrity (B-IBI) for Chesapeake Bay.  Estuaries 20:149-158.

F.  Data Quality

(Please provide appropriate references and location of documentation if hard to find.)

(27) Were the data collected according to an EPA-approved Quality Assurance Plan?  

If no, complete questions 28a – 28d:

Yes.  The EPA-approved Quality Assurance Project Plan is available from:

http://www.baybenthos.versar.com/docs/LTBQAPP02.PDF

(28a) Are the sampling design, monitoring plan and/or tracking system used to collect the data over time and space based on sound scientific principles?

Yes.  The Benthic Monitoring Program is a general monitoring program conducted to optimize precision and accuracy in characterizing annually the status and trends of benthic condition in Chesapeake Bay.  The program contains two primary elements: a fixed site monitoring effort directed at identifying trends in benthic condition, and a probability-based sampling effort intended to estimate the area of Chesapeake Bay and ten strata with benthic communities meeting or failing the Chesapeake Bay Program’s benthic community restoration goals.  The design has evolved over time.  The program is an extension of Power Plant assessments initiated in the early 1970’s.  Currently, fixed site sampling in Maryland continues trend measurements in spring and summer at 27 sites, 23 of which have been sampled since the program’s inception in 1984, 2 since 1989, and 2 since 1995.  The Virginia program conducts trend measurements at 21 sites.  Probability-based summer sampling was instituted in 1994 in Maryland, and 1996 in Virginia.  

(28b) What documentation clearly and completely describes the underlying sampling and analytical procedures used?

Please refer to the Quality Assurance Project Plan:

http://www.baybenthos.versar.com/docs/LTBQAPP02.PDF

and the Methods Section of the Annual Report.  The Annual Report can be found at:

http://www.baybenthos.versar.com/referenc.htm

(28c) Are the sampling and analytical procedures widely accepted as scientifically and technically valid? 

Yes.  Detailed sampling and analytical procedures can be found in the Quality Assurance Project Plan:

http://www.baybenthos.versar.com/docs/LTBQAPP02.PDF

The B-IBI and its application to Chesapeake Bay has undergone extensive technical review and peer review.  Please see references in Section 21 above.

(28d) To what extent are the procedures for quality assurance and quality control of the data documented and accessible?

QA/QC protocols can be found in the Quality Assurance Project Plan:

http://www.baybenthos.versar.com/docs/LTBQAPP02.PDF

(29) Are the descriptions of the study or survey design clear, complete and sufficient to enable the study or survey to be reproduced? 

Yes.  Please refer to the Quality Assurance Project Plan:

http://www.baybenthos.versar.com/docs/LTBQAPP02.PDF

and the Methods Section of the Annual Report.  The Annual Report can be found at:

http://www.baybenthos.versar.com/referenc.htm

The methods for the calculation of the Chesapeake Bay B-IBI can be found at:

http://www.baybenthos.versar.com/docs/ChesBayBIBI.PDF

(30) Were the sampling and analysis methods performed consistently throughout the data record?

The sampling and analysis methods have been performed consistently throughout the data record, but the design of the program has evolved over time.  For a history of the program please refer to:

http://www.baybenthos.versar.com/history.htm

The probability-based estimates are the result of reviews conducted jointly by the Maryland and Virginia benthic monitoring programs.  A program review in 1996 examined program objectives, analysis techniques, and power to detect trends.  One objective that emerged from the program review process was a goal of producing baywide area estimates of benthic community condition with known and acceptable uncertainty.  That goal is now an inherent part of benthic monitoring activities in Chesapeake Bay.  The sampling design and methods in both states are compatible and complementary.

(31) If datasets from two or more agencies are merged, are their sampling designs and methods comparable?

Yes.  The continued presentation of estimates of Bay area meeting the Chesapeake Bay program’s benthic community restoration goals, rather than the Maryland or Virginia estimates only, reflects improved coordination and unification of objectives among the Maryland and Virginia benthic monitoring programs.  The sampling design and methods in both states are compatible and complementary.

(32) Are uncertainty measurements or estimates available for the indicator and/or the underlying data set?

Yes.  The B-IBI and the stratified random sampling design allow inference of areal condition with known precision and uncertainty.  Please refer to the Data Analysis Section of the Quality Assurance project Plan:

http://www.baybenthos.versar.com/docs/LTBQAPP02.PDF

(33) Do the uncertainty and variability impact the conclusions that can be inferred from the data and the utility of the indicator?

No.  The probability-based design and the B-IBI are robust to variability in the data.  The B-IBI was shown by Alden et al. (2002) to be sensitive, stable, robust, and statistically sound:

•Alden, R.W. III, D.M. Dauer, J. A. Ranasinghe, L.C. Scott, and R.J. Llansó.  2002.  Statistical verification of the Chesapeake Bay Benthic Index of Biotic Integrity.  Environmetrics 13:473-498.  

However, the B-IBI has a greater error (i.e., lower correct classification efficiency) in the tidal freshwater and oligohaline than in high salinity environments.  This variability is partially due to the various natural stresses in low salinity habitats, which in general make the application of biological indicators less reliable than those established for more saline habitats.

(34) Are there noteworthy limitations or gaps in the data record?  Please explain.

No, there no major limitations or gaps in the data record.

G.  Additional Information

(optional)

(35) Please provide any other information about this indicator you believe is necessary to aid communication and any prevent potential miss-representation.

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