Hem Nalini Morzaria Luna
Department of Botany
University of Wisconsin-Madison
341 Birge Hall; 430 Lincoln Drive
Madison WI 53705.
Enhancing germination and establishment in salt marsh restoration
This project is being developed at the Tijuana River National Estuarine Research Reserve, in San Diego, CA; it involves comparing the Friendship Marsh, an 8-ha constructed marsh, with Oneonta Slough a natural area, as well as greenhouse experiments. Some of the questions being asked include how do plant communities initially develop in restored marshes? How do seeds come into the marsh? And once the seedlings start growing, what determines whether they will survive and constitute an adequate community. I have begun this project by studying seed dispersion, by looking at which and how many seeds are carried in by the tide out of the natural area and into the restored marsh; and if herbivores, in this case rabbits, move seeds into the area. I have been setting seedtraps, which are large mesh boxes, in the channels during high tides; the traps collect any floating materials in the water. I have also collected rabbit pellets around the upper tide line. I am currently analyzing these samples by tracking how many and what plants germinate. So far I have observed Perennial Pickleweed seeds and plant fragments going into the restored marsh. Pickleweed canopies are the preferred habitat of the endangered Belding's Savannah sparrow. I have also begun to study the seedbank (accumulation of seeds in the soil) in restored and natural marsh, by taking cores and assessing the number of seeds for each plant species in them. In the marsh plain of Oneonta Slough I began an experiment to reintroduce Annual Pickleweed (which disappeared in this area after a tidal closure event in 1983), I planted around 600 plants and I am tracking survival and seed production.
Through learning at what rate do seeds come into the restored marsh, by what means; when and how quickly do they accumulate in the soil my results will lead to recommendations for improving salt marsh restoration efforts. By trying to reintroduce Annual pickleweed, I hope to set additional guidelines for the establishment of native vegetation.