Friday, August 10, 2007
Exhibit Halls 1 and 2, San Jose McEnery Convention Center
As part of a larger goal to provide public revegetation projects in Los Angeles County with genetically-appropriate propagules, we identified 10 areas with significant native plant populations for the collection of suitable local seed within the San Gabriel River watershed. Conservative estimates indicate that less than 10% of the native riparian vegetation is intact within California, with less than 2% remaining in L.A. County. In L.A., which survives on 70-80% imported water, the use of seed/propagules from indigenous plant populations that are adapted to local climate conditions is most appropriate for public revegetation projects. Support for this approach was achieved in January 2004 when the County Board of Supervisors adopted Landscaping Guidelines and Plant Palettes for the Los Angeles River. This document requires the use of indigenous plant propagules for LA River re-vegetation projects. Detailed collection data provides valuable information on these remnant populations. We found many of the open space areas remaining within the County are environmentally-degraded, tick-infested, steep slopes, often overgrown with poison oak. Collection focused mainly on public open space land where permits were easier to obtain. We produced a Short List of sixty-nine, horticulturally-interesting local native plants that are appropriate, durable, beautiful, easy-to-grow in nurseries and transplant well. Focusing on public lands in north-east L.A. County, we collected ~315 vouchers for 54 species (~3 vouchers/ species/population) within 23 plant families from the Short List. We photographed specimens and collected vouchers now deposited in the Rancho Santa Ana Botanic Garden Herbarium. We captured location information using a Trimble GeoExplorer3 then stored them in ArcMap. We mapped the populations for future reference and collection for propagation and are working to expand the project to other areas in the County. Next step is outreach to landscape-professionals and politicians about the advantages indigenous plants offer when restoring local landscapes.
