An Evaluation of Habitat Use in Natural and Restored Tidal Marshes in San Francisco Bay, CA

Legislation mandating the protection and restoration of wetlands has led to numerous projects to reverse the trend of wetland loss in the San Francisco Bay region. While natural tidal marshes are characterized by broad, high marsh plains dominated by perennial plant species, restored sites are often lower in elevation, have more annual plant species, and lack well-developed tidal channels, at least during the first 6 to 10 years. Waterbird and fish habitat utilization was compared within a restored wetland (Hayward Regional Shoreline) and a natural marsh (San Leandro Bay). In abundance, the natural marsh site supported greater number of waterbirds during all stages of the tide compared to the restored marsh. Shorebirds tended to utilize the high marsh to a greater extent in the natural marsh and did not utilize the high, artificial islands in the restored wetland. Public access in the restored wetlands investigated greatly diminished wildlife use. There was no significant difference in fish utilization between the natural and restored marsh, however, fish generally preferred sheltered mud habitats over open water or vegetated areas.