Section 508 Navigation
National Trails Training partnership Skip Navigation
HomeAbout usTrailsWhat's hotCalendarTrainingResources & libraryPartnersJoin usStore

Wildlife and environmental issues

Hosted by

Design and Management Stategies to Avoid or Reduce Adverse Effects of Public Access on Wildlife

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)

It is clear that there are gaps in our scientific knowledge on specific effects of public access on wildlife. However, the potential for adverse effects is apparent, and as more scientific information is generated, many managers will choose to use precaution and design and manage public access to avoid or minimize potential adverse effects to wildlife.

photo: sign along trail

Sign at Oyster Point on the Bay Trail reminds visitors of the importance of habitat


Furthermore, though better science is obviously needed in order to make better informed decisions about management of public access, science alone will not dictate the existence or design of public access. Rather, science is part of a larger framework that also includes public values and benefits, laws and regulations, and overall management objectives of specific areas.

Within this larger public policy framework, some sites may be managed to preclude or severely limit public access, while at other sites a variety of uses may be allowed and actively managed to find a balance between resource preservation, education, recreation, and low-impact transportation use. It is within this larger management framework that managers are striving to find the optimal balance between use and protection, and where specific design and management strategies can be employed to avoid or minimize potential impact.

History and Trends

The issue of how to balance protection and use has historically been discussed in the field of park and wilderness management. The United States National Park System, for example, has the dual management objectives of preserving natural resources while providing for high quality recreational and public access opportunities. As visitation to the U.S. National Park system greatly increased, so did concern over how to manage these potentially conflicting goals. The National Park System initially focused its management efforts on the theory of “carrying capacity,” a concept adopted from the field of ecology which refers to the number of individuals of any one species that a particular habitat can support. This concept was applied by the Park System in the 1960s as a way of formulating management objectives based on the number of visitors a particular park could support in a given time frame (per day, per season, etc.), in terms of the impacts on park resources. Over the years, the concept of carrying capacity has broadened to include the social aspects of the visitor experience (i.e., how user numbers affect the personal experience of visitors in terms of overcrowding). More recently, the concept is expanding from that of a visitor numbers only to include type of visitor use. Carrying capacity is now defined by the National Parks as “the type and level of visitor use that can be accommodated while sustaining acceptable resource and social conditions that complement the purpose of a park.”

The concept of carrying capacity as applied to park management has led to another management construct, called “limits of acceptable change” or LAC. The notion behind LAC is that despite the attempt to establish carrying capacities for individual areas, given the demand for public use of parks some degree of impact or change is inevitable, and furthermore, that limiting use is just one management tool of many to address impact and may not even be the most effective. The question of how much change is too much is determined by inherently subjective standards (informed by science) and is addressed by establishing limits of acceptable change. The limits are based on a description of the desired future condition, and contain the identification of indicators of quality, the formulation of monitoring techniques, and the development of specific management actions to ensure the limit of acceptable change is not exceeded.

On a smaller, more local, scale, there is a burgeoning body of literature on public access siting and design that addresses or identifies ways to minimize human use effects on wildlife. Again, the majority of this work focuses on strategies for inland, forested habitats, but some information can be adapted to the coastal environment. For example, the State of Colorado has undertaken considerable work on trail siting and design and has prepared an extensive bibliography, as well as a unique and extremely useful handbook for public access managers. The Waterfront Regeneration Trust in Canada has produced a similar, though less extensive, publication generated from their personal experience with the Waterfront Trail located on the north shore of Lake Ontario.

photo: sign along trail

Boardwalk along the Bay Trail


For coastal states, the public access and wildlife compatibility topic is fast becoming a very important management issue as the states work to actively encourage public access to their shorelines while also protecting natural resources. In a recent assessment by the National Oceanic and Atmospheric Administration, “State Enhancement Grant Assessments and Strategies: Public Access,” eight coastal states (including California) cited wildlife and public access compatibility issues as an area of concern. Oregon, for example, has developed a Rocky Shores Management Strategy which, in part, addresses the impact of public access on rocky shore habitat.

In the Chesapeake Bay region, several initiatives to address public access and wildlife compatibility issues are underway. For example, the Virginia Ecotourism Association offers a voluntary eco-tour certification program for Virginia’s coastal areas that aims to protect natural resources while encouraging the growth of Virginia’s tourism industry. In addition, the Hampton Roads Planning District Commission in Virginia, in partnership with several local, state and federal agencies, and other interested parties, is developing a memorandum of agreement to address conflicts between watercraft
and impacts generated by watercraft (including impacts on sensitive wildlife). The intention of the MOA is to generate a voluntary water-zoning system that would identify certain areas for certain types of craft (e.g., non-motorized craft use only in smaller, narrower tributaries).

The Maryland Department of Natural Resources has created design guidelines for trails in specific areas that meet the Critical Area Act, which encourages public access to the shoreline while protecting sensitive habitats. The design guidelines provide recommendations to local officials, planners, consultants, and contractors on how public walkways in the Critical Area can most effectively meet the goals and requirements of the State and local programs. A 100-foot buffer is designated for sensitive areas in Maryland. Public walkways are encouraged to be designed outside of the buffer (or in “Buffer Exemption Areas”) where possible; access within the buffer areas is permitted “at intervals” to “provide opportunities for education and access to the water.” Mitigation for public walkways in buffer areas is encouraged even in Buffer Exemption Areas, at a 2:1 or 3:1 ratio depending on the location of the walkway.

It is expected that more initiatives addressing the issue of public access and wildlife compatibility will continue to emerge from various resource and regulatory agencies, as well as non-profit organizations and private parties. The sharing of knowledge and personal experiences among those faced with this issue will continue to play an important role as the demands for both public access and resource protection continue to increase in both inland and coastal environments.

Public Access and Wildlife Compatibility Survey

Though the scientific literature on this issue is relatively sparse and provides little, if any, conclusive guidance, managers all over the world are employing various siting, design and management strategies in an effort to avoid or minimize potential adverse effects of public access on wildlife. In an
effort to gain more knowledge on the use of design and management strategies, BCDC staff (with assistance from the Policy Advisory Committee) conducted a survey of land managers from coastal and Great Lake states nationwide. The goals of the survey were to gather further observational information on recreational effects on wildlife, and to document on-site experiences with specific design and management strategies and how those strategies have or have not been an effective tool in avoiding or reducing adverse effects on wildlife from human activities.

The survey was mailed to 362 land managers from coastal and Great Lake states around the country. The selected participants manage local, state and federal reserves, parks, refuges, open spaces, recreation areas, and wildlife management areas. The sites managed by survey participants contain sensitive habitat areas, such as wetlands or sandy beach, and allow public access for recreational activities.

Significant interest in this topic nationwide and a vigorous follow up effort resulted in 157 surveys returned, for an excellent response rate of 43 percent. Responses to the survey were tabulated, where possible. Many of the survey questions were open-ended and generated a variety of qualitative responses. Responses to open-ended questions were reviewed, categorized, and summarized to the greatest extent possible. The survey documented on-site experiences with specific design and management strategies and how those strategies have or have not been an effective tool in avoiding or reducing impact on wildlife from human activities.

An extremely high response rate to the survey, wide national distribution of respondents, and the large number of respondents with a high level of responsibility indicates a strong nationwide interest and high degree of importance assigned to the access and wildlife compatibility topic. Varied size and make up of sites contributed to a wide distribution of data on access and wildlife compatibility. Respondents had varying backgrounds (scientific, managerial, etc.), employed a wide variety of observational techniques (formal and informal) and were responding for a wide variety of local, state, and federal sites of various sizes and with various missions and management strategies.

Observed or documented short-term and long-term effects of human activities on wildlife at specific sites were varied (respondents were not asked to correlate observed or documented effects on wildlife with other factors such as degree of use of site or effectiveness of design and management strategies to avoid or reduce impacts on specific sites).

  • The most commonly reported immediate effect on wildlife was from unleashed dogs, followed by walking/jogging.
  • The most commonly reported observed or documented long-term effect on wildlife was from humans feeding wildlife, followed by fishing.
  • The activity types most commonly reported as having no observed or documented effects on wildlife were photography, followed by birdwatching.

All of the survey respondents employed one or more design or management strategy(ies) (such as trail types, separation features, prohibition of trail development, area closures, visitor number limits, activity type restrictions, user behavior restrictions, education and outreach programs, and wildlife management/monitoring) on their sites. The vast majority of all respondents felt that their design and management strategies were at least somewhat effective in avoiding or reducing recreational impacts on wildlife.

The most commonly employed strategy was education and outreach programs. The second most commonly employed strategies were activity type restrictions and user behavior restrictions, followed closely by area closures and separation features. Limits on visitor numbers was the least frequently employed strategy.

Vegetative buffers were the most common type of separation feature employed. Vegetative buffers were also reported as the most effective type of separation feature for avoiding or reducing impacts on wildlife from human activities, followed by bridges/boardwalks and viewing platforms/overlooks, then fencing.

Loop trails were the most common type of trail present and were reported as the most effective trail type for avoiding or reducing impacts on wildlife from human activities.

Overnight and seasonal closures were the most common type of area closures employed.

The most common type of activity restrictions employed were boat restrictions (including jet skis), motorized vehicle restrictions (including ATVs/ORVs), and bicycle restrictions. The most common type of behavior restrictions employed were pet restrictions.

The most common type of enforcement mechanisms employed were signs, followed by staff patrols.

The most common type of education and outreach mechanisms employed were written materials (pamphlets, brochures, etc.), followed by interpretive signs/selfguided trails.

Respondents reported that combinations of strategies were very effective and that the success of design and management strategies depends greatly on available funding and staff to employ, monitor and enforce strategies.

Public Access Siting, Design and Management Strategies

Techniques that address potential public access effects on wildlife are categorized into one of three variables that characterize the user/wildlife interaction. These three management categories are: siting and design; use management; and wildlife management.

Each of the three elements (the access route itself, the public access users, and the wildlife in the
public access area) can be managed independently or, more likely in combination, to avoid or minimize adverse effects. Obviously, manipulation of one variable will affect the others, and the distinction between the three variables may not always be precise (i.e., seasonal closure of a trail may be considered a manipulation of the visitor, as well as a manipulation of the trail itself). However, categorizing management techniques into these three variables provides a useful means of organization for discussion and planning purposes.

1. Trail Siting and Design

The initial planning and design of the public access site is the first means by which to avoid or minimize adverse effects on wildlife. Recognizing that public access features will change the landscape in some way and recognizing that the public access site will have an effect on the surrounding area (which may extend for quite some distance), an initial site analysis of the area is important. With a thorough understanding of the area and the species which inhabit it currently (or are projected to inhabit the area in the future such as with seasonal use areas or planned habitat restoration sites) and an analysis of the projected human use of the area, an evaluation of access siting and design alternatives can be undertaken to help avoid or minimize potential adverse effects on wildlife.

Planning an access area with a regional view of the environment can help balance the needs of wildlife and the public across a larger perspective. For example, knowledge of adjacent land uses can help determine the siting, design and management of public access. Some strategies to employ with a regional perspective in mind include: avoiding disturbance of smaller, isolated habitat patches; aligning access along the edge, rather than bisecting undisturbed areas, avoiding wildlife breeding areas, and aligning a trail along an already disturbed area (which may also facilitate restoration of the area as part of the trail development). Furthermore, an analysis of the site may determine that public access is not appropriate at all.

Siting and design of public access can incorporate many types of buffers (or access controls) that constrain public access to a defined area, such as fencing, vegetation, boardwalks, and viewing areas. Buffers or transition areas between public access and wildlife habitat can provide a physical barrier to keep users out of sensitive areas, may allow for enough physical space for wildlife to avoid public, and may contribute additional habitat. Different types of buffers may be appropriate in different public
access areas.

Many strategies employed during siting and design address the issue of “visitor satisfaction.” When weighing the potential impacts of public access on wildlife versus the potential benefits, how gratifying the experience is for the user will be a factor in the degree of potential wildlife impact associated with trail use. For example, access routes that do not provide some sort of access to desirable areas such as the shoreline or a wildlife area may inadvertently encourage the creation of numerous alternative informal pathways created by users. Informal pathways can increase adverse effects on an area from physical trampling of vegetation, by creating access to sensitive areas, by dispersing use within a sensitive area, and by lessening the degree of predictability of users to wildlife. Similarly, a hidden habitat or viewshed may frustrate users, and may induce users to find it on their own (i.e., a shoreline obstructed by a high levee may lead to the periodic trampling of levee vegetation as users attempt to achieve the visual access). Lastly, strategies that limit access by concentrating use (such as boardwalks and viewing platforms) may lead (depending on use levels) to negative social outcomes of user overcrowding, which again may lead to creation of informal pathways as users attempt to avoid crowds.

2. Use Management

Use management strategies consist of restrictions on the amount, type and behavior of visitor use as well as educational/behavior modification approaches. As discussed previously, the concepts of carrying capacity and limits of acceptable change as applied to public access areas may assist managers in deciding whether to employ use management strategies that limit the amount of visitors in an area, but limits on numbers of users is just one possible management strategy. Furthermore, it has been shown in some cases that the greatest degree of impact may occur at a fairly low level of use, while increasing numbers of users does not notably increase the degree of impact.

Instead, managers may allow the amount of use to go unregulated and instead work to reduce the amount of impact each user causes by managing the impact of the individual users, such as limiting the type of use at a particular site (i.e., pedestrian only trails) and the behavior of the users (i.e., leash requirements, seasonal restrictions, guided trails). Use management may also consist of periodic closures of public access routes based on the use of the site by wildlife (such as during breeding seasons or at high tide when species are forced upland).

An important aspect of these types of use management is control over the predictability of user locations and activities. Managing use to facilitate predictability of human actions may increase the potential for certain species of wildlife to adapt to those actions. Some obvious challenges for planners and managers in employing many of these use management strategies include the need for a great deal of site-specific knowledge and the potential for high personnel costs.

Finally, increasing the knowledge of users regarding the habitats and species at a site, the implications of users’ actions, and the reasons behind user restrictions is an often cited management tool that can help facilitate an interesting and meaningful user experience as well as reduce potential adverse effects to the site. Educational materials, guided tours, and interpretive panels are all examples of ways to increase the knowledge of users.

3. Wildlife Management/Monitoring

Management of the wildlife itself at a site may help to avoid or minimize adverse effects of public access on specific species. Monitoring of wildlife at a site can provide for extremely useful information on which the success of efforts to protect wildlife can be based. Habitat modification, restoration,
enhancement, and creation are strategies that may provide benefits for both wildlife and public access goals, including diversifying available habitat for wildlife to provide alternative areas for foraging, nesting and resting.

The use of some wildlife management techniques, such as creation of alternative nesting habitats to encourage wildlife to nest in areas away from public access routes, must be weighed against the creation of a less “natural” environment. Wildlife management techniques may also be opposed by the public. For example, there has been negative public reaction to the elimination of predators, though predator elimination techniques can be an effective (though potentially costly) management tool to combat the secondary impacts of public access (i.e., the creation of predator access to wildlife along trails).


Siting, design and management strategies may be used to avoid or minimize adverse effects of public access on wildlife. The relative success of specific siting, design and management strategies will vary from site to site. Appropriate strategies depend on the habitat, species present, present and future species use of habitat, adjacent land uses, types and frequency of users, specific management objectives of the site, public input, available funding, etc.

Because the relative advantages and disadvantages of many strategies will vary, they are most appropriately provided as guidelines for public access development, rather than policies. The existing advisory Public Access Design Guidelines were based on the San Francisco Bay Plan policies and also reflect past permit decisions of the Commission and recommendations of the Commission’s advisory Design Review Board on individual project designs. The 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 that 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 -

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

Related topics:

More resources:

page footer

Contact us | Mission statement | Board of directors | Member organizations | Site map | Copyright | NRT | NTTP