SAV Habitat Requirements
and Restoration Targets:
Technical Synthesis III
Lee Karrh
SAV workgroup chair
A brief history
• TechSyn 1 was published in
– Largely water column based
– Simple pass/fail evaluation of
each habitat requirement (HR)
– Fixed restoration depths (1
and 2 meter)
• TechSyn 2 was published in
– Created a model to combine HRs
– Attempted to model attenuation at
the leaf surface
– Evaluated light availability at the
leaf surface for multiple
restoration depths, as opposed to
1 or 2 meters only
From: Batuik et al., 1992
Summary of TS1 and TS2 Habitat
Why is TS3 necessary?
• For direct restoration projects,
even places that met existing
habitat requirements had poor
• The Watershed Model (version
5.3) did not adequately
estimate observed SAV
abundances in calibration runs
using existing HRs
Cerco, 2010
Pertinent conclusions from STAC
review of SAV restoration
Evaluate extremes of temperature and
clarity rather than just average
Consider the interacting effects of
multiple stressors (particularly
temperature, clarity and salinity) and
temporal dynamics and sequencing
Develop SAV restoration strategies that
are responsive to climate change
Pertinent From STAC Review of
SAV module of the Model
SAV potential:
A. Improve model relationships between TSS (particle size, organic content, etc.) and
epiphyte loads (biofouling, periphyton).
B. Test the ability of the model to duplicate case study areas where there have been
observed improvements in habitat conditions and SAV resurgence.
C. Quantify the effects of other stressors (salinity, sediment biogeochemistry) on SAV
biomass dynamics.
D. Incorporate multiple species (including non-native) potential with species-specific
physiology into each SAV cell rather than generic SAV.
E. Further develop SAV to habitat feedbacks.
SAV area:
A. Refine how bottom sediment properties affect species-specific SAV recruitment
and survival.
B. Improve simulations of year-to-year variations in SAV species-specific recruitment
potential including colonizer species.
C. Include biological disturbance components of mortality.
D. Refine relationships between SAV canopy height and SAV light requirements.
TS3 will allow us to:
• Review current habitat requirements and water clarity
standard and determine if they are stringent enough to
allow for the resurgence of SAV.
– Are 13% and 22% of incident light at the plant sufficient?
– Revisit ambient nitrogen, phosphorous and chlorophyll habitat
requirements in relation to anticipated reductions in loadings via
TMDL/WIP process, provide guidance to Water Quality Standard
• Improve modeling results for SAV growth in linked
Watershed/Hydrodynamic Model (the Chesapeake Bay
– Modeling results to date have been too poor to incorporate into
model runs
• Will global change require different habitat requirements
in the future?
• Revised/re-considered habitat requirements will
improve direct SAV restoration (i.e.
– As recommend by STAC review of 2011
• Revised habitat requirements will provide
greater explanatory power when preparing SAV
information for managers and the public (i.e. Bay
Barometer, report cards etc.)
• Use ecosystem services evaluation
– Evaluate effectiveness of TMDL/WIP process relative
to SAV
– Quantifying water quality feedbacks due to SAV to
allow Chesapeake Bay Model to account for water
quality improvement as SAV is restored (currently not
a component of the Model)
– Determine economic value of SAV for management
and public informational products
Topics to be addressed
SAV Restoration
Global change
Sea level rise, coastal erosion and sustainable shorelines
CO2 levels
Precipitation (variable river flow) and global dimming (incident light)
Ecosystem services provided by SAV in Chesapeake Bay
SAV habitat requirements (light, sediments, waves)
Habitat criteria for established versus restored SAV beds
Impact of pioneer species on SAV resurgence/restoration
Feedbacks and resilience of SAV populations (genetics) and communities
Large versus small scale restoration
Shoreline hardening effects on SAV
Ecological functions of SAV (interactions with fisheries, nutrient uptake, carbon
sequestration, wave/resuspension reduction, habitat value, improving habitats for other
species, water quality challenges (i.e. DO improvements)
Economic impact of SAV serving the above functions
Identification of knowledge gaps in SAV research, restoration and management
Analysis/Synthesis Partners
Tom Arnold
Katia Engelhart
Maile Neel
Chuck Gallegos
Brooke Landry
Mike Kemp
Chris Kennedy
Evamaria Koch
Ken Moore
Bob Orth
Chris Patrick
Nancy Rybicki
J. Court Stevenson
Chris Tanner
Lisa Wainger
Don Weller
Richard Zimmerman
Dickinson College
University of Maryland Center for Environmental Science, AL
University of Maryland College Park
Smithsonian Environmental Research Center
Maryland Department of Natural Resources
University of Maryland Center for Environmental Science, HPL
George Mason University
University of Maryland Center for Environmental Science, HPL
Virginia Institute of Marine Science
Virginia Institute of Marine Science
Smithsonian Environmental Research Center
US Geological Survey, Reston, VA
University of Maryland Center for Environmental Science, HPL
St. Mary’s College
University of Maryland Center for Environmental Science, CBL
Smithsonian Environmental Research Center
Old Dominion University
Rich Batiuk
Michelle Gomez
Rick Ayella
Lee Karrh
Rusty Butt
Leslie Orsetti
Anne Swanson
NOAA Chesapeake Bay Program
US EPA Chesapeake Bay Program
US ACE Baltimore District
DC Fisheries
Chesapeake Bay Commission

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