Mangrove Cove

Delta
Mangrove Cove Management Plan
7.9 Monitoring success of widgeon grass & seagrass planting
Annually lay out a marked string line across the area planted with seagrasses. Make sure the
line extends beyond the planted area at both ends. Use a fixed point to run the line from (eg a
post on the Trafalgar). Photograph the extent of the planted area, if it is small enough. If the
area is large, photograph several evenly spaced points along the line. Be sure to include the
tape in the photographs. The spread of the plants can be estimated from this measure, as well
as the density (coverage) of the plants.
7.10 Monitoring mangrove expansion
Mangrove expansion is an expected occurrence in the reserve however expansion that results
in a monoculture, or that completely hides the Ships Graveyard, is not desirable. Should
annual salting of the wrecks and saltmarshes be undertaken, then several photo points should
be set up at the Cove to monitor the effectiveness of this program.
Photo points should be placed perpendicular to embankments, looking across the leading edge
of the mangroves. There should be two locations where no salting will be occurring
(mangrove/mudflat or mangrove/saltmarsh interfaces), and two locations where salting will be
occurring (mangrove/saltmarsh interface). Suggested locations for the photo points are shown
in Figure 11 – Monitoring locations. Each view should include a fixed object (eg parts of a
wreck or a stake) that is a known size. This will provide a scale in the photographs. A short
stake or other fixed point should be driven into the ground where the camera will be placed
for each photograph. In this way each year’s photograph will be able to be overlaid on the
previous year to detect change.
Heights and breadths of the mangrove fringe may be calculated from these photographs. A
new photo point may be established as the mangrove zone expands.
7.11 Monitoring saltmarsh plantings
Should an area for saltmarsh retreat be constructed and planted, a record shall be kept, by the
developer, of the original plantings and their placements (a planting plan). A fixed photo
point shall be established on the filled area of the site with a view that encompasses the
saltmarsh retreat site as shown in Figure 11 – Monitoring locations. A photograph shall be
taken on completion of planting and at least annually after that.
To determine specific species’ success, a line transect, as detailed in the Waterwatch SA
Estuarine Monitoring Guidelines (Coleman and Cook, 2003) may be undertaken, if desired. A
suggested location for a transect in the saltmarsh retreat zone is shown in Figure 11 –
Monitoring locations. Record the details on the vegetation transect monitoring sheet provided.
7.12 Using aerial photographs to map habitat change
Aerial photography is the easiest method of identifying the extent of gross habitat change. A
simple classification of georectified aerial photography into three classifications (mangrove,
saltmarsh and mud flat) will suffice. If aerial photography is purchased from Mapland every
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