Propagation and Reintroduction of Arenaria paludicola (Marsh Sandwort) and Nasturtium gambelii (Gambel’s Watercress)
Barry S. Nerhus, Jr.
Faculty Mentor: Peter A. Bowler
Arenaria paludicola (Caryophyllaceae) and Nasturtium gambelii (Brassicaceae) are two wetland indicator vascular plant species, native to California, that grow in freshwater marshes. The original, natural distribution of A. paludicola rangedfrom Washington to the Santa Ana River watershed in Orange County. The original, natural distribution of N. gambelii extended from the San Francisco Bay area to the Santa Ana River watershed. Arenaria paludicola and Nasturtium gambelii are two federally listed Endangered plant species. In collaboration with the U.S. Fish and Wildlife Service, efforts to enhance the tiny wild populations are being made by propagating vegetative cuttings of genetically distinct individuals of Arenaria paludicola and Nasturtium gambelii from all known natural populations. These cuttings are being grown for reintroduction at the Santa Barbara Botanic Garden and the University of California, Irvine Arboretum. The propagation protocol requires that vegetative cuttings carefully be taken from wild stock, and their cut stems dipped in the root promoting hormone Rootone before potting in an artificial wet-propagation environment. These plant fragments are grown for several months in special wet-propagation basins as new roots develop, with each cutting being cultivated individually in submerged pots. The plan for re-introduction of Arenaria paludicola and Nasturtium gambelii is to survey and select suitable sites within existing permanently protected freshwater marsh habitats in the southern region of the species’ historic ranges. When sites have been selected, reintroduction will be accomplished during the spring of 2007 in conjunction with the U.S. Fish and Wildlife Service.