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Bay Area Trail studies habitat impacts of trail access

Public Access and Wildlife Compatibility Project confronts the question of how to balance the sometimes competing interests of improving public access and preserving and enhancing wildlife habitat in the Bay. Download the Public Access and Wildlife Compatibility Report (pdf 232 kb)

From San Francisco Bay Conservation and Development Commission (March 2001)

The Public Access and Wildlife Compatibility Project was initiated in partnership with the Association of Bay Area Government's Bay Trail Project. The Bay Trail Project, with BCDC assistance, took the lead in facilitating original field research to measure public access impacts on avian species that inhabit San Francisco Bay.

"Access to the Bay allows the public to discover, experience and appreciate the Bay's natural resources and can foster public support for Bay resource protection, including habitat acquisition and restoration."

BCDC, with Bay Trail Project assistance, concentrated on improving its knowledge of siting, design, and management strategies to avoid or reduce impacts by undertaking a comprehensive assembly and analysis of available information, collecting further observational and anecdotal information through a survey of land managers, and establishing an advisory committee to help generate policy recommendations.

In the 35 years since BCDC was created, public access to the shoreline expanded significantly from four miles in 1965 to over 200 miles today, with more public access being added each year. Demand for public access continues due to an increasing Bay Area population and the desirability of shoreline access experiences. Furthermore, there is a demand for a diversity of access experiences, including both along urban waterfronts and in more natural areas.

PROJECT CONCLUSIONS

photo: sign along trail

Boardwalk and observation platform to enable visitors to experience the wetlands

The following conclusions are based on the background information and research results, and supplement the conclusions that are in the existing San Francisco Bay Plan (Bay Plan) public access findings and policies. These conclusions were agreed upon by the Policy Advisory Committee and serve as the basis for the revisions to the Bay Plan public access findings and policies.

1. San Francisco Bay provides a variety of habitats for diverse populations of plants, fish and wildlife. The Bay presently sustains nearly 500 species of fish, invertebrates, birds, mammals, insects and amphibians. Out of the nearly 500 species of wildlife and aquatic life associated with the Estuary, 30 are listed as threatened or endangered under the state and federal Endangered Species Act. The Bay provides habitat for over one million shorebirds and is the winter home for over 50 percent of the diving ducks along the Pacific Flyway.

2. The San Francisco Bay allows the public to discover, experience and appreciate the Bay's natural resources and can foster public support for Bay resource protection including habitat acquisition and restoration. Public access can provide for recreational activities, educational and interpretive opportunities, and means for alternative transportation. There is an increasing demand for diverse kinds of public access experiences.

3. There is a need for more, well-designed, scientific studies of effects of human activities on wildlife, both on a local scale in the San Francisco Bay Area, and on a national scale in similar habitats with similar recreational uses. Specifically:

a. There is much to learn on the relationship of recreational frequency and spatial scale to wildlife impacts;

b. The potential ability for certain species to become adapted to some degree of human interaction is a poorly understood though important factor;

c. Baseline data are needed both for comparison purposes and to help isolate disturbance factors (i.e., recreation caused disturbance versus other factors such as poor water quality or natural variability), and;

d. There is a need for scientific data regarding the effectiveness of specific design and management strategies to avoid or reduce impacts of human activities on wildlife.

4. There is evidence that public access may have adverse effects on wildlife. Adverse effects on wildlife from human activities may be both direct (such as harassment or harvest) and indirect (such as habitat modification), and effects can be both immediate and long term. Immediate effects may include: nest abandonment (which may increase risk of predation of eggs or young), flushing, increased stress, which can lead to reduced feeding or site abandonment. Long-term effects may include decreased reproductive success, decreased population within species, or decreased number of total species. If improperly sited, public access may fragment habitats and serve as predator access routes to wildlife areas.

5. Over time, wildlife may adapt to the predictable actions of humans. However, not all individuals in a population adapt equally well. Furthermore, adaptation to human activity may leave wildlife more vulnerable to harmful human interactions (such as hunting).

6. Different kinds of disturbances have different effects on different species: effects are context dependent. For example, the type and severity of impacts on wildlife will depend on the type of human activity, and the predictability, frequency, magnitude, timing, season, and location of the activity. Impacts will also depend on the particular species, group size, age, sex, and whether the species is a resident or migratory.

7. Potential adverse effects from public access can be addressed through the employment of siting, design and management strategies to avoid or minimize adverse effects, including such strategies as use restrictions, buffers, periodic closures or the prohibition of public access in specific areas. Siting, design and management strategies can be effective in avoiding or reducing adverse effects on wildlife.

8. If the public is provided with rewarding and fulfilling formalized access, people will be less inclined to create their own ad hoc informal pathways. Informal pathways can increase habitat fragmentation and interaction between humans and wildlife, may result in less predictability of human use for wildlife, may create predator access routes to wildlife habitat, and may result in vegetation tram-pling and erosion.

9. The relative advantages and disadvantages of specific design and management strategies vary from site to site. Appropriate strategies depend on a variety of factors such as type of habitat, species present, adjacent land uses, types and frequency of users, planned future use of area, management objectives, public input, available funding, etc.

10. Detailed information on the advantages and disadvantages of specific siting, design and management strategies are most appropriately provided as guidelines for public access development, rather than policies. The existing advisory Public Access Design Guidelines, adopted by the Commission in 1985, are in need of revision and provide an appropriate format for information on siting, design and management strategies to avoid or minimize adverse effects on wildlife.


For more information: San Francisco Bay Conservation and Development Commission, 50 California Street, Suite 2600, San Francisco, California 94111 - Phone: (415) 352-3600 - Fax: (415) 352-3606 - http://www.bcdc.ca.gov/

Download the Public Access and Wildlife Compatibility Report (pdf 232 kb)

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