The use of historical data in the restoration of the avifauna of the Ballona Wetlands, Los Angeles County, California

The historical Ballona Wetlands in coastal Los Angeles County were once one of the most significant coastal wetland systems in southern California, but were greatly reduced in extent and ecological function by the mid-1900s. Starting around 1900, the Ballona area saw the near-complete elimination of two major vegetation types (riparian scrub and freshwater marsh), and during the early 1960s, it experienced the loss of most of its tidal salt marsh to a major development, Marina del Rey. Attempts to recreate lost habitat, all since 1990, have achieved mixed results in terms of restoring lost natural communities, including birds. Of the 38 bird species known to have been extirpated from the valley as breeding or winter resident species since 1900, only 11 have become reestablished. Remarkably, all of the reestablished species are characteristic of a single, recently-restored habitat type, freshwater wetland. By contrast, species dependent on other native habitats of the area (notably grassland, coastal scrub, and salt marsh) have registered only extirpations, with essentially no reestablishment despite recent habitat restoration. Though some of these extirpated species no longer occur in coastal Los Angeles County, those that do should be afforded special consideration in future restoration efforts.