Tidal Wetlands Abundance

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Chesapeake Bay Program Indicator Framework

Reporting Level Indicators

Indicator and Data Survey

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: Tidal Wetland Abundance Indicator

(3) Data Set Description:  

For what purpose(s) were the data collected? (e.g., tracking, research, or long-term monitoring.) To determine the abundance of tidal wetlands in acres within the Chesapeake Bay.

Which parameters were measured directly? Which were obtained by calculation?  C-CAP data used to develop this indicator is satellite imagery at 30m resolution.

(4) Source(s) of Data:  The Coastal Change Analysis Program (C-CAP) is a nationally standardized database of land cover and land change information, developed by NOAA, using remotely sensed imagery for the coastal regions of the U.S.  C-CAP products inventory coastal intertidal areas, wetlands, and adjacent uplands with the goal of monitoring these habitats on a one-to-five year cycle.

Is the complete data set accessible, including metadata, data-dictionaries and embedded definitions?  If yes, please indicate where complete dataset can be obtained.  Contact Data Source

(5) Custodian of Source Data (and Indicator, if different):  Source Data: Chris Kinkade (NOAA CBPO), Nate Herold (NOAA)

(6) CBPO Contact:  Peter Claggett, USGS CBPO pclaggett@usgs.gov,  and  Krystal Freeman, Living Resources Subcommittee Stafffreeman.krystal@epa.gov

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)  data collection is on a one-to five year cycle Only 1996, 2001, and 2005 are available to date.  Data from 1984 and 1992 are being analyzed and should be available in 2008.

(8b) What is the short-term trend? (10-year trend) There is a negative trend in tidal wetland abundance from 1996 -2005 however the difference is not statistically significant See 35. for more details.

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

(10b) What is the key story told by this indicator? Although the changes are not significant on a Bay-wide scale, there are some significant changes on a local scale.  Aerial photography in specific locations around the Bay, such as Blackwater National Wildlife Refuge in Maryland’s eastern shore, has been used to visually document significant loss of wetlands (see Figure 1.).  The blue pixels overlain on the aerial photograph represents the acres of wetlands lost between 1996 and 2005.

(11b) Why is it important to report this information? Status and trends, in relation to a goal or target:  According to NOAA’s Coastal Change Analysis Program data from tidal regions of the Bay, there were 286,630 acres of tidal wetlands in 1996, 286,403 acres in 2001, and 283,946 acres 2005.  In next year’s assessment, we will be able to provide comparable data for 1992 and 1984.  This indicator is not associated with a goal, but it will inform the development of a wetland protection goal.

 (12b) What detail and/or diagnostic indicators are related to this reporting level indicator?   Wetland Restoration 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):  (1984-2005)

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

(a) Source Data: one-to five year cycle

(b) Indicator:  annual

(15) For annual reporting, month spatial data is available for reporting: 

D.  Spatial Considerations

(16) Type of Geography of Source Data (point, line polygon, other):  Satellite Imagery

(17) Acceptable Level of Spatial Aggregation (e.g. - county, state, major basin, tributary basin, HUC):  N/A

(18) Are there geographic areas with missing data?  No  

If so, where?

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

(a) Chesapeake Bay (estuary)

(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.

(20) Can appropriate diagnostic indicators be represented geographically?  

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

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

(23) Are any tools required to generate the indicator data (e.g. - Interpolator, watershed model) No

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

(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

(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)  No

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? See below

(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?  See Below

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

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

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

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

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

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

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

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

(34) Are there noteworthy limitations or gaps in the data record?  See Below

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

Proposed Tidal Wetlands Abundance Indicator

Chesapeake Bay Program Monitoring and Analysis Subcommittee

Advance Briefing Materials for the December 18-19, 2007 meeting

BACKGROUND

Several reporting-level indicators were identified as “gaps” in the 2005 Assessment (e.g. “not quantified this year”).  The Implementation Committee (IC) agreed to focus on filling these gaps in order to feature them in the 2006 Assessment.  Responsible subcommittees were charged to work with the Monitoring and Analysis Subcommittee (MASC) to develop new indicators, or identify options for resolving issues related to a subcommittee’s inability to develop or approve a new indicator, and to present the indicators or options to the IC no later than February 2007.

In summer of 2006, the Wetlands Evaluation Task group (WET) considered options on how to report the status of tidal wetlands throughout the Bay by utilizing the most comprehensive data available.  Several options were discussed but one (UMCES’ Marsh Condition Index) provided the most detail through a basin-wide, peer reviewed and field validated approach.  In early 2007, this option was reviewed and discussed among WET, the Living Resources Subcommittee (LRSC), MASC and approved by IC pending analysis of additional years’ data; however such analysis was cost prohibitive (estimated at $200,000).

OPTION / RECOMMENDATION

The Coastal Change Analysis Program (C-CAP) is a nationally standardized database of land cover and land change information, developed by NOAA, using remotely sensed imagery for the coastal regions of the U.S.  C-CAP land cover change data consists of change maps, which identify the location of changes that have occurred, and a change database that records the quantity and category of these conversions.  

This model provides LRSC with the following option:

Utilize continuous source of C-CAP data available for the Chesapeake Bay region to determine the abundance of tidal wetlands in acres. C-CAP products inventory coastal intertidal areas, wetlands, and adjacent uplands with the goal of monitoring these habitats on a one-to-five year cycle.  

ISSUES

1.Defining Tidal Wetlands: When using the C-CAP data, estuarine scrub/shrub, estuarine forested, and estuarine emergent wetlands are all included in the definition of tidal wetlands.

2.Defining Area of analysis: NOAA’s estuarine drainage area (see Figure 3.)

3.Mapping Tidal Wetlands:  The C-CAP satellite imagery is on 30m resolution and may not detect small changes over large areas.  The C-CAP program is, however, moving toward incorporating high resolution imagery to improve and validate their assessments.  Until that is available, a more detailed geographic breakdown of wetland area could help to convey the change in tidal wetland abundance. 

4.Mapping Change:  The changes that occur in most areas are so small that they are difficult to visually perceive in the satellite images.  

5.Data Accuracy:  C-CAP data categorization of estuarine emergent wetland has a confidence/ accuracy of 95%.  There is however question about the reasonability of C-CAP indicating that wetland area has become agricultural area; this is counter intuitive.  This could be depicted in the indicator as a range of wetland loss: one end of the range including the acres of wetlands that became agricultural land and the other end not including these acres. 

6.Cost:  There are other methods for mapping wetland trends, but few of these, if any, could be applied cost effectively across a landscape as large as the Chesapeake Bay watershed.  NOAA and USGS have already funded the C-CAP data collection and plan to continue to fund it in future years. The Chesapeake Bay Program Office is fully funding a new Landscape Analyst position which will be responsible for future analysis, therefore no additional funds will be required to populate this indicator.

7.Establishing a Baseline:  The baseline for the indicator will be set when the analysis of the 1984 and 1992 data has been completed (likely in 2008).

INTERPRETATION

The data show that there is a negative trend in tidal wetland abundance in the Chesapeake Bay. According to the land change statistics there was a 2,600 acre loss between 1996 and 2005.  However, this change is not statistically significant at the Bay-wide scale due to limitations of the data. This indicator is not intended to speak to the quality or health of the wetlands being analyzed; it is simply a quantitative tool. 

Although the changes are not significant on a Bay-wide scale, there are some significant changes on a local scale.  Aerial photography in specific locations around the Bay, such as Blackwater National Wildlife Refuge in Maryland’s eastern shore, has been used to visually document significant loss of wetlands (see Figure 1.).  The blue pixels overlain on the aerial photograph represents the acres of wetlands lost between 1996 and 2005.

Figure 1.  Blackwater National Wildlife Refuge

TidwaterWetlandsFigure1.gif

FUTURE ACTIONS

CBP GIS will have capability to do high resolution sampling verification.  There is also an effort underway by NOAA to analyze data from 1992 and 1984 which we will be able to include in the indicator once available.  Ultimately, the CBP partners hope to use this indicator as a tool to target management approaches in areas shown to be the most vulnerable to tidal wetland loss and conversion.

Figure 2. Tidal Wetland Abundance Indicator Graphic

TidwaterWetlandsFigure2.gif

Figure 3.  C-CAP data area of analysis

TidwaterWetlandsFigure3.gif

INFORMATION ABOUT THE NEW INDICATOR

1.Name of indicator: Tidal Wetland Abundance

2.Status and trends, in relation to a goal or target:  According to NOAA’s Coastal Change Analysis Program data from tidal regions of the Bay, there were 286,630 acres of tidal wetlands in 1996, 286,403 acres in 2001, and 283,946 acres 2005.  In next year’s assessment, we will be able to provide comparable data for 1992 and 1984.  This indicator is not associated with a goal, but it will inform the development of a wetland protection goal.

3.Narrative information and data 

oPlease refer to attached spreadsheet.

oAdditional information about this indicator is included in a presentation provided to the LRSC on November 29, 2007 (http://www.chesapeakebay.net/pubs/ca...ion_3_8480.ppt).

4.Source of data: The Coastal Change Analysis Program (C-CAP), NOAA Coastal Services Center

5.Indicator contact information: Peter Claggett, USGS CBPO pclaggett@usgs.gov,  and Krystal Freeman, Living Resources Subcommittee Staff freeman.krystal@epa.gov

DECISION REQUESTED:  

Support the recommended approach to fill this Indicator gap in the Health and Restoration Assessment.

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