Land Retirement Demonstration Project

The Potential for Using Locally-collected Seed in San Joaquin Valley Restoration

Presented To:

Society for Ecological Restoration, California (SERCAL)
Bass Lake, California 2005

by

Nur P. Ritter*, Curtis E. Uptain, and Patrick A. Kelly

Abstract

For a variety of reasons, it is essential that locally-collected seed be utilized in restoration efforts. However, the San Joaquin Valley has been subjected to a tremendous amount of development, and only 5% or so of the region remains relatively undisturbed. For the past six years, we have been conducting restoration research on the Valley's retired agricultural lands. During that time, we have increasingly apportioned resources towards locating areas that support native plant species. Concurrently, we have had to expand our concept of what constitutes a "local" source; and now include sites within a 50 mile radius. To date, we have located 41 upland collecting sites, ranging in size from a few hundred square feet to > 500 acres. In all, 156 native species have been encountered. These species represents only a small fraction of those known historically for the area. More importantly, although few of these species would be considered rare on the state level, a significant number are clearly rare on the local level. Nearly two-thirds (64.7%) of the species were encountered in only 1-3 collecting areas. Atriplex spinifera, a species that once dominated a large portion of valley floor, and which is still fairly abundant in the south valley, was found in only two sites within the collecting radius. Furthermore, some species were represented by single individuals. Despite limiting our collecting to upland habitats, approximately one-seventh (14.4%) of the species were either obligately or facultatively associated with wetlands; hence, their potential for upland restoration is uncertain. The restoration species pool is further diminished when elevation and soil types are considered, as many of the collecting sites were situated in the foothills, or on alluvial fans. Undoubtedly, many additional species and populations exist within the study area. However, the surveying and collecting activities outlined here represent a significant effort, and it is clear that the amplification of local seed stocks needs to be accorded priority status when any large-scale restoration is considered.