Tuesday, November 4, 2008

Seeding for diversity…

Yesterday Kim and I went out to our eastern Long Island Sound (LIS) restoration sites and overseeded with seeds from several donor meadows. We were fortunate to collect a large number of seeds from Fishers Island and Mulford Pt. this year and it is time we got them out of the nursery. We will be planting some for restoration, some for grow out in the creek behind the lab, but a large number were destined to increase the genetic diversity at our existing restoration sites.

Because we created the meadows at St. Thomas and Terry’s Points with adult shoot transplants the genetic diversity in these new meadows is probably low. We make every effort to collect shoots from various locations to ensure the highest diversity, but given that these stable meadows could be single clones there is no guarantee that what we collect is genetically diverse.

In an effort in increase genetic diversity at these sites we overseed with seeds collected from various donor populations in the Sound. We have found through the years working at these high energy sites that seeds do not recruit very effectively in the absence of adult shoots. Apparently, the seeds need the moderating influence of these shoots to reduce currents and turbulence that might otherwise dislodge or overly bury the seeds. In the presence of adult shoots, however, they do recruit and grow.

The seeding at St. Thomas involved spreading the seeds at the leading edge of each large patch of grass that we encountered. There is a “leading edge” because the current always runs in one direction given the shape of the shoreline. This way, as the seeds migrate down current they will have the greatest opportunity to be trapped by the stems and other bottom irregularities. If we placed them near the center of these areas, there is a greater chance that the seeds might be transported out of the patches and beyond where they could effectively recruit.

The conditions at Terry’s Pt. are different so I simply sprinkled the seeds throughout the large patches. Other seeds were broadcast outside the patches to see if they could recruit under here.

During our planting we broadcast approximately 500,000 seeds between the two sites. Three quarters of these were planted at St. Thomas site and the balance at Terry’s. Only time will tell how manh of these seeds recruit.


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