Submerged aquatic vegetation (SAV) abundance and diversity in the tidal Potomac River and estuary

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Submerged aquatic vegetation (SAV) abundance and
diversity in the tidal Potomac River and
estuary By Nancy Rybicki, Jurate Landwehr,
Edward Schenk, and Julie Baldizar Goal provide
managers with information to help them understand
variation in SAV coverage and determine
strategies to meet the SAV restoration goal.
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Variation in SAV coverage, Potomac River SAV data
from http//www.vims.edu/bio/sav
No data
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Solar radiation
Water clarity is the primary factors influencing
SAV abundance. Literature review and analyses
indicated MLRs of 13 light for the fresh and
oligohaline and 22 for mesohaline to polyhaline
SAV community (Carter et al. 2000, Batiuk et al.
2000, Kemp, et al. 2004)
Light
Water Temperature
Wind Speed
Phyto- plankton
Total Suspended Solids
Nutrients
River Flow
Epiphytes
Secchi depth of 0.7m 13 light at 1m
Submersed Aquatic Vegetation
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1) EVALUATION OF SUBMERGED AQUATIC VEGETATION
(SAV) AND WATERFOWL POPULATIONS WITH RESPECT TO
EXOTIC SPECIES AND IMPROVING WATER QUALITY 2)
POSSIBLE CAUSE OF VIRGINIA TRANSPLANTS 2003
2004 3) MAP SHOWING POTENTIAL AND CONTINUEING
USGS WORK
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Improved water quality in an estuary with exotics
enhances SAV diversity and waterfowl habitat, by
Rybicki and Landwehr
Study Area
Data source SAV species, USGS and DC govt SAV
coverage, VIMS Water quality, MDDNR Waterfowl,
Audobon Christmas bird count
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SAV productivity is density specific SAV
coverage, in hectares
Rybicki and Landwehr, in process
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(No Transcript)
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Conclusions 1985-2001 Potomac River- Productivity
of native, as well as exotic, SAV species was
shown to vary with factors affecting water column
light attenuation (TSS, Chlorophyll a). Winter
waterfowl increased significantly with SAV
coverage, despite dominance by exotics. SAV
productivity was largely driven by Hydrilla
productivity 1985-2001 Previous years propagules
(tubers, seeds, etc) may dampen the effect of
environmental variation Our findings support
management strategies to improve water clarity
and reduce nutrient concentration in order to
protect diversity and waterfowl habitat
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Exploring Causes of a Seagrass Transplant Failure
in the Potomac River (Virginia) Mitigation for
loss of SAV at Wilson Bridge construction site
We monitored a seagrass transplant site (Judith
Sound) and a reference site (Dameron Marsh), in
VA. The transplant site was one of six SAV
transplant sites in the Potomac that have only
been marginally successful since transplanting
began in 2000 (written communication, Justin
Reel) . March to November, of 2003 and 2004, at
both sites we measured habitat variables monthly,
including sedimentation and erosion, shoot length
and burial, salinity, and light attenuation.
Natural eelgrass at reference site and eelgrass
tranplanted in fall 02 and fall 03 (written
communication, Justin Reel) did poorly in 2003
and 2004
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Exploring Causes of a Seagrass Transplant Failure
in the Potomac River (Virginia) Mitigation for
loss of SAV at Wilson Bridge construction site
Figure 1. Precipitation and salinity during 2003
and 2004 at the transplant site and reference
site. Precipitation data from Norfolk
International Airport
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Exploring Causes of a Seagrass Transplant Failure
in the Potomac River (Virginia) Mitigation for
loss of SAV at Wilson Bridge construction site

1. Both sites were above the median 22 percent light
   level
2. The percent of shoot that was buried was greater
   at the transplant site (22 percent) than at the
   reference site (11 percent), although both
   percentages were below levels shown to be
   detrimental to eelgrass survival (Veermaat and
   others 1997).
3. Monitoring data support the conclusion that
   salinity not erosion or accretion, were the
   primary factors responsible for the decline of
   eelgrass at both sites.
4. Low sediment fertility may also play a role in
   lack of success at the eelgrass transplant site.

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Potomac integrative analysis will enhance USGS
SAV studies and other potential studies to
explain ecosystem change to help assess the
effectiveness of restoration strategies
2003 SAV Maryland
Tracking sediment sources using isotopic tracers
(Allen Gellis, USGS)
Wetland restoration and sediment accretion studies
Relationship between environmental variables and
species of SAV
Field investigations of SAV health, sediment
characteristics, water quality, and maximum depth
of SAV, w/ many cooperators
Dameron Marsh natural SAV health as a reference
site for SAV transplants
Image from MDDNR website