In marsh restoration and creation projects plant material is often obtained from local nurseries, but sometimes it is obtained from nurseries in other parts of the country. In recent years there has been a growing discussion as to how far from a restoration site should material be obtained. Ten years ago we initiated a study to determine how plant genotypes collected from different locations along a latitudinal gradient affect the functioning of a salt marsh ecosystem. In a created salt marsh in Delaware planted with several different genotypes of each of three plant species we found that numerous ecosystem functions were dependent upon plant genotype. For example, a genotype of Spartina alterniflora from Georgia produced the most shoot biomass for fueling the detritus-based food web. It also produced the largest quantity and deepest distribution of belowground biomass for fueling the soil food web. A genotype from Massachusetts produced a shallower root and rhizome system but contained richer carbohydrate reserves that correlated with a higher respiration rate for the edaphic community. Also, its shorter canopy and narrower leaves resulted in less shading and greater benthic microalgal populations. Similar differences were found among genotypes of the two other species. In additional studies we have found that somaclonal variants produced from tissue culture can also affect ecosystem function differently. Perhaps the intraspecific variation within species can be exploited for optimizing function in restored or created marshes, especially those in very perturbed sites. In a current study we are finding that genotypic differences within species that fringe the marsh-upland border may prove useful in efforts to block salt marsh invasion by Phragmites australis, a marsh plant that has become an invasive menace in salt marshes along the north and mid-Atlantic coast during the past several decades.

Key words: genotype, Phragmites australis, restoration, salt marsh, Spartina alterniflora