Tuesday, September 27, 2011

Clam Creek Marsh Monitoring 9/23

Clam Creek Marsh Monitoring-We Return
Will Davis

Clam Creek is a scenic spot for horseback riding, fishing, shell collecting, and just enjoying a day.  It is located on Jekyll Island, one of the eight barrier islands off the Georgia coast.  Jekyll is one of the four barrier islands accessible by car.  In addition to the fun activities, mentioned above, Clam Creek is home to Georgia’s second state bird, the mosquito.  Due to improper drainage and a restricted tidal flow when a non-vehicular bridge was constructed, mosquito larvae flourished in standing water from rain that was of a lower salt content than the water naturally found in the area.  In addition to the abundance of mosquitoes, the normal flora, including Spartina, Juncus, and Distichlis were displaced by less salt tolerant plants.
To solve this issue, the culvert pipes that were restricting flow both in and out of the area were removed and a bridge with a larger non-restrictive opening was constructed.  The types and health of the three marsh plant species needed to be monitored to keep an eye on how the project was progressing.  That is where we came in…. again.

Our fearless crew took the most remote areas to monitor, fighting through mud, water, and marsh plants only to find more mud, water, and marsh plants.  Then we measured plant growth in pre-determined meter square segments.  Spartina, Juncus, and Distichlis were checked for numbers, percentage of ground covered by each, and also the height of the largest Spartina was measured.   The fauna that were found on previous surveys were absent on these segments so we saw no crabs, mussels, or snails.  These segments were also the furthest from the tidal flow.

The salt hardy plants appear to be making a comeback in these areas.  The higher salinity brought about by the better circulation has helped these plants to get a foothold, and with the non salt tolerant plants being removed by the salt, the marsh is regaining lost ground.   The standing water being drained and replaced by a water of higher salinity not only brings the marsh plants back but also reduced the breeding ground for mosquitoes.  Even though some mosquitoes will breed in salt marshes, mosquitoes need still water for the larvae to reach adulthood.  Even the tidal flow of water can disrupt the life cycle.

The results from lessening the restriction on the waters would seem to be less mosquitoes and a more gradual or soft edge for the Spartina growth.  With the path no longer as an edge, the grasses are not met with a severe change between one side of the path to the other.  Further monitoring is required to see if this is the final answer, but after several visits it seems to be working.

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