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Bay Grass Scarring Project
In 1997, interpretation of the aerial photography taken for the annual seagrass
survey revealed an alarming trend. Seagrass beds were being heavily scarred by
commercial fishing and recreational boating. The Maryland General Assembly
passed a bill in 1998 to curb the fishery impact on the seagrasses. This
legislation effectively removes commercial fishing pressures from the seagrass
beds, and the Department of Natural Resources will monitor the recovery of
seagrass beds impacted by commercial fishing over time. In addition, beginning
in the summer of 1998, the Department of Natural Resources undertook
a study to determine the extent of damage caused by
recreational boating to seagrasses, and to propose management activities to
minimize this damage. This work is ongoing. Annual aerial surveys and
on-the-ground random quadrangle sampling, indicate that recreational boating
affects density of seagrass beds, particularly in areas near jetski livery
operations and waterfront bars. However, several of the owners of these
establishments have voluntarily taken steps to reduce the overall intensity of
the scarring activities. These include marking channels to concentrate activity
to relatively small areas (have a small area of intense impact versus large
areas of more diffuse impacts) and providing alternatives to boaters wishing to
anchor. Currently there is no information on the effectiveness of these efforts,
the Department will continue to monitor these areas to ascertain if there is any
long-term benefit to these strategies, and perhaps incorporate similar ideas
into a forthcoming Water Management Plan.
Fort Meade Laboratory Activities
The DNR operates a laboratory at the Environmental Protection Agency’s
Environmental Science Center on the grounds of the Fort George G. Meade Army
installation. The bay grass lab at Ft. Meade has been used since 1998 to
experiment with indoor growth and propagation techniques and for raising bay
grasses. The goal is to develop simple procedures to allow mass production of
bay grasses for transplanting and restoration activities. Micropropagation
techniques and turion production methods are also being perfected to increase
the survival of transplants used in restoration. Currently, research is being
conducted on: redhead grass (Potamogeton perfoliatus),
sago pondweed (Stuckenia
pectinata), and wild celery (Vallisneria americana).
Water Chestnut Harvest
Water chestnut, (trapa natans), is an invasive exotic floating
plant species recently rediscovered in the Upper Chesapeake Bay. While open
water beds of water chestnut can be removed by mechanical harvesters, hand
picking is required to eliminate plants from shoreline areas. Volunteer efforts
typically occur in late June. For more information, contact Mark Lewandowski at the
Department of Natural Resources (410)260-8630 or
mlewandowski@dnr.state.md.us.
Bay Grasses Mapping Project
Current bay grass restoration goals are based upon information collected between
1971 and 1990. Since large-scale declines occurred in the late 1960's and early
1970's, current bay grass restoration goals may not accurately reflect the
restoration potential in the Chesapeake Bay. Suitable aerial photography
collected between 1930-1960 has been uncovered which can provide pre-decline bay
grass distributions in the Chesapeake Bay.
Objectives of this project include:
1) Identifying, and digitizing aerial photography archives for imagery of the
littoral zones in the tidal portions of the Chesapeake Bay in Maryland. These
beds will represent an historical, pre-decline benchmark of a healthy bay grass
community in these regions of the Chesapeake Bay.
2) To combine the Maryland historic bay grass distributions with Virginia
historic surveys to develop a comprehensive baywide reference dataset using a
computer-based GIS (ArcInfo).
3) To use the Baywide historical bay grass dataset and water clarity criteria to
develop methods and criteria for new bay grass restoration acreage goals for the
entire Bay and each of its tidal tributaries as well as bay segment-based
designated use attainment status.
Blossom Point Project
There is a dearth of information regarding the effects of breakwaters
(both construction effects and presence in the water) on bay grasses. There are
several reasons to expect that breakwaters can positively influence bay grass
beds. Obviously, any vegetation within the foot print of a breakwater project
would be lost as the construction of the structure takes place (US Army Corps of
Engineers, 1981). In addition, changes in hydrography, and the resultant change
in sediment dynamics, could alter coverage. Accretion of sediment in the lee and
scour on the exposed side (US Army Corps of Engineers, 1984; US Army Corps of
Engineers, 1992; Hsu et al., 1993; US Army Corps of Engineers, 1998) of a
breakwater can either smother or erode away bay grasses, reducing coverage.
Conversely, a breakwater will create more quiescent wave energy environments in
the lee of the structure that can be conducive to bay grass colonization and an
increase in coverage (Roseboom et al., 1989; Blama, 1993; Davis and Landin,
1997; Dan et al., 1998; Allen et al., 1999). In a study of 20 breakwater
projects in Maryland’s Chesapeake Bay, the effects of the presence of
breakwaters on bay grass coverage were analyzed. Overall, the coverage in a
given area of the Chesapeake Bay appears to be driven by region-wide processes
and that the presence of a breakwater does little to change bay grass coverage
trends as identified by annual aerial survey. In Chesapeake Bay Program (CBP)
segments that have increasing bay grass coverage, the areas in the immediate
vicinity of the breakwater usually show a concurrent increase. Conversely, if a
CBP segment is showing a decline in coverage over time, the areas adjacent to a
breakwater show similar decreases as well. There are eight exceptions to this.
Three breakwaters showed a localized positive effects (more bay grass in the
vicinity of the breakwater after construction relative to the surrounding
Chesapeake Bay Program segment), possibly due to the structure providing a
refuge against waves or other disturbance (Blama, 1993). However five
breakwaters had negative effects (less bay grass after construction relative to
the surrounding CBP segment). In all eight of these cases, the effects of the
breakwaters were weak. Even with these exceptions, bay grass coverage in the
vicinity of a breakwater seems to track coverage with the surrounding CBP
segments, though possibly at different relative rates. However, this study did
not consider changes in bay grass density, species composition or biomass in the
vicinity of a breakwater project.
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