To begin to find answers to these questions, the Bay Trail Project initiated a study to look at if and how recreational trail users impact shorebirds. The Wildlife & Public Access Study, launched in 1996, is being led by an independent research team. Specifically, the Study is examining the potential effects of non-motorized recreational trail use on the diversity, abundance, and behavior of shorebirds and waterfowl that use mudflat foraging habitat along the Bay Trail. The Study will build a foundation of statistically valid data that can begin to guide the development and management of trails in a manner that respects and protects wildlife.		Above: Observers counting birds at the Mountain View study plot.

The basic research question of the Wildlife and Public Access Study is "does trail use affect wildlife." The study more specifically asks, "what are the potential effects of non-motorized recreational trails on the diversity, abundance, and behavior of shorebirds and waterfowl that use mudflat foraging habitat adjacent to the Bay Trail." After extensive field review, three locations were used for the study: Bothin Marsh in Mill Valley (Marin County), Redwood Shores (San Mateo County), and Shoreline at Mountain View (Santa Clara County) (see map at left). At each location, paired trail and non-trail (control) sites were selected and 100-foot by 100-foot study quads were set up. Paired sites were ecologically and physically similar; in each case, the sites were on levees adjacent to a tidal wetland where mudflats are exposed at low tide. Data were collected for 24 months at paired sites in the three locations. Observations were made four times a month in four-hour observation periods simultaneously at both the trail and control sites, on two week days and two weekend days. Left: Trail site locations.

Three types of data were collected at each site. The first compares the abundance and species diversity of shorebirds found at sites that have developed shoreline trails with those observed at similar undeveloped control sites. The second data set records shorebird behavioral responses to various types of trail users relative to behavior at undisturbed control sites. Finally, data are collected on the type and intensity of recreational use at the three locations. For more details about the study questions and design, refer to the Wildlife and Public Access Study Proposed Research Plan Report and the Wildlife and Public Access Study Site Selection Report (see reports section). Right: Researchers measure and set up study plots for observation.

• Produce results that will inform future siting, implementation, and design decisions for the Bay Trail. 
  
  
• Enrich the dialogue about wildlife and public access among trail planners, land owners and managers, resource agencies, planning agencies, environmental groups, bird organizations, and other interested parties. 
  
  
• Provide a valuable study design that can be replicated by other agencies, trail planners, and conservation groups around the country.

• Generate statistically-testable data to determine the effects of trail users on the diversity and abundance of shorebirds in mudflat habitats adjacent to trails as compared to non-trail control sites.
  
  
• Evaluate the effects that trail users have on the behavior of shorebirds in mudflat habitats.
  
  
  

Study Team

Principal Investigators: Jana Sokale, Environmental Planner, Adjunct Faculty Member, San Jose State University Dr. Lynne Trulio, Associate Professor and Chair, Department of Environmental Studies, San Jose State University Site Supervisors: Debra Chromczak (Mountian View) Ingrid Harrald (Redwood Shores) Lisa Hug (Mill Valley) Sean Casto (Interim Supervisor, Redwood Shores)

Above: A researcher prepares for observation.

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