Are Seagrasses in Charlotte Harbor Migrating Landward in Response to Expected Sea Level Rise

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Are Seagrasses in Charlotte Harbor Migrating
Landward in Response to Expected Sea Level Rise?
Charlotte Harbor Watershed Summit March 27, 2008
Judy Ott FDEP South District Laboratory Environme
ntal Assessment Restoration Partners
Environmental Assessment Restoration Charlotte
Harbor Aquatic Preserves
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This Presentation Briefly Describes Seagrass
Transect Monitoring in Charlotte Harbor
Background Questions Relating to Sea Level
Rise Field Analysis Methods Results
Discussion Conclusions
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BACKGROUND FDEP Charlotte Harbor Aquatic
Preserves Coordinates Seagrass Transect
Monitoring
To Assess Seagrass Conditions Throughout
Charlotte Harbor. At 50 Fixed Transects. Every
Fall Since 1999. Consistent with SWFWMD
Protocols. With Help From Many Partners.
Source CHAPs
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CHAPs Seagrass Transects Compliment Other
Seagrass Monitoring Aerial Mapping Programs
Source SWFWMD
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Water Quality Monitoring Programs
Coastal Charlotte Harbor Monitoring
Network Random Grids
FDEP, SCCF WMD Continuous Data Loggers
Charlotte Harbor Estuaries Volunteer Water
Quality Monitoring Fixed Sites
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... To Help Manage the Estuaries for Long Term
Health Balanced Uses.
Source CHAPs
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Studies Show Seagrasses have been Relatively
Stable in Charlotte Harbor in the Last Decade
Seagrass Deep Edge Hasnt Change Significantly.
(Stearns et al 2007, Boswell et al 2006, Ott et
al CEHR 2006)
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Studies Show Seagrasses have been Relatively
Stable in Charlotte Harbor in the Last Decade
Seagrass Deep Edge Hasnt Change Significantly.
(Stearns et al 2007, Boswell et al 2006, Ott et
al CEHR 2006)
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Seagrass Acreage Hasnt Change Significantly.
(Corbett et al 2006, Kaufman/SWFWMD 2007)
1982 2003 Change in Seagrass Acres in Charlotte
Harbor
From Corbett 2006
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Seagrass Acreage Hasnt Change Significantly.
(Corbett et al 2006, Kaufman/SWFWMD 2007 )
2004 2006 Change in Seagrass Acres in Charlotte
Harbor

• 18,364 acres
• 225 acres increase
• 1 change

From SWFWMD/Kaufman 2007
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But Seagrass Density is Declining in Some
Estuaries. (Boswell et al 2006, Stearns et al
2007)
1999 2004 Change in Seagrass Density in
Charlotte Harbor
Frequency of Quadrats Surveyed
Estuary
From Boswell et al 2006
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But Seagrass Density is Declining in Some
Estuaries. (Boswell et al 2006, Stearns et al
2007)
1999 2006 Change in Seagrass Species Density in
Charlotte Harbor
From Stearns et al 2007
From Boswell et al 2006
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Seagrass Transect Data is Used by CHNEP to Set
Resource Based Water Quality Targets

Based on Seagrass Deep Edge Water
Clarity. Allows Flexibility in Reaching Water
Quality Targets.
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But Sea Level is Rising
Water Resource Planning in Sarasota Bay (Clark et
al.)
Mangrove Restoration in Charlotte Harbor (Tattar
et al).
Oyster Research in Estero Bay (Volety et al).
SWFRPC Analyses in Charlotte Lee Co.
Anecdotal Observations.
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the NEPs are Incorporating Sea Level Rise in
CCMPs Goals.
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QUESTIONS BIGGY How will Sea Level Rise Affect
Seagrass Depths, Acres, Abundance Water
Quality Targets in Charlotte Harbor? SPECIFICALLY
Have Seagrasses in Charlotte Harbor Migrated
Landward in Since 1999?
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METHODS CHAPs Seagrass Monitoring Protocols
Monitored Each Fall. 50 Fixed Sites in Charlotte
Harbor Estuaries. Sites Grouped by Estuary.
Source CHAPs
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Fixed Transects from Shore to Seagrass Deep
Edge. 1 m2 Grids at Defined Intervals Along Each
Transect. 5 Seagrass 6 Physical Parameters. Use
Braun Blanquet Abundance Categories. Tide Stage
Observed Relative to MHWL (Barnacles).
Braun Blanquet Abundance Categories
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Water Depths are Corrected to Mid-Tide using
Observed Tides Stages Tide Ranges from Nearest
NOAA Tide Gauge.
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CHAPs Data Analyses Use Access SPSS.
Todays Analyses made with Excel.
Based on 44 Stations, Excluding those with No
Seagrass or Data for gt 3 Years MYR01
MYR02 PR01 PR02 MC01 PIS08
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RESULTS
Location of Shoreward Edge of Seagrasses Did Not
Move Significantly from 1998 2007.
Only 4 of 44 Seagrass Transect Sites Showed the
Shallow Edge of Seagrasses Moved Significantly
Shoreward.
?
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Water Depth Did Not Increase Significantly From
1998 2007.
MEAN DEPTH AT SHALLOW EDGE REFERENCE POINT
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No Estuaries Showed Significant Changes in Water
Depth at Shallow Edge Reference Point.
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But 1 Estuary Region as a Whole Showed
Significant Increases in Water Depth at Deep Edge
of Seagrasses.
87 cm SE2.1 R2.01 P.43
124 cm SE4.6 R2.01 P.54
128 cm SE5.2 R2.03 P.36
147 cm SE2.3 R2.01 P.05
158 cm SE5.3 R2.030 P.22
169 cm SE5.5 R2.03 P.15
176 cm SE6.7 R2.05 P.12
186 cm SE4.8 R2.37 P.00
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DISCUSSION
Improved Accuracy of Seagrass Transect Locations
Each Year with GPS.
Improved Precision of Seagrass Transect Locations
Improved Each Year with More Stakes.
Improved Description of Seagrass Abundance Since
2005 with Addition of Shoot Counts Total
Abundances.
Improved Analysis Availability of Seagrass Data
Access Data Base Summary Reports.
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CONCLUSIONS
Based on Preliminary Analysis of Seagrass
Transect Data, Seagrasses Do not Appear to have
Moved Shoreward since 1998.
Depth Measurements Collected with Seagrass
Transect Data Did Not Find a Significant Increase
in Water Levels in Charlotte Harbor since 1998.
More Precise Tide Measurements During Seagrass
Monitoring will Enhance the Ability to Detect
Smaller Changes in Water Depth.
More Rigorous Statistical Analyses are Needed to
Relate Seagrass Changes to Sea Level Rise..
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CONCLUSIONS
Based on this Recent Seagrass Reports, Mean
Deep Edge of Seagrass Growth is An Effective Tool
for Evaluating Water Quality Targets.
Seagrass Distribution Abundance Reflect
Seasonal Changes in Seagrass Conditions Related
to Rainfall Changes in Salinity Regimes.
Continuing Seagrass Transect Monitoring
Improving Tide Estimations will Enhance Links
between Seagrass Health, Water Quality Targets
Sea Level Rise.
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Thank You to All the Many People Who Helped with
Seagrassing Since 1998
FDEP Neil Ayers, Erin Dykes, Stephanie
Erickson, Trink Fletcher, Debbie Horner, Carla
Kappmeyer, Ray Leary, Jennifer Nelson, Mindy
Schneider-Brown, Heather Stafford, Jennifer Thera
Celia Stearns
CHNEP Catherine Corbett
CHEC Renee Duffey Jason Hale
MANY OTHERS INCLUDING Rick Bartleson, Jaime
Boswell, Brian Cotterill, Ken Cummins, Katie
Fuhr, Kris Kaufmann, Ray Kurz, Jim Lacascio,
Ronda McKenzie, Bob Repenning, Tom Ries, Karen
Shudes, Betty Staugler, Kendra Willett, Peggy
Wilzbach Bill Van Oyen
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For More Information, Please Contact
FDEP in Punta Gorda South Distinct
Laboratory Environmental Assessment
Restoration [phone] Charlotte Harbor
Aquatic Preserves [phone] or Judy
Ott Until April 2 judith.ott_at_dep.state.fl.us Star
ting April 3 jott_at_swfrpc.org [phone] Ext
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