Background Information


The information on this page provides some background information about the resolution proposing human-free habitat.

There is a growing awareness among wildlife biologists and conservationists that relatively human benign activities or even our mere presence adversely affects many wildlife species. Those activities need not be hunting, chasing, shooting, destroying habitat, or in any way overtly harassing the wildlife, but simply hiking or even quietly passing by.

Human Disturbance of Wildlife

Chapter III of the handbook Managing Development for People and Wildlife, prepared by Clarion Associates and the Colorado Division of Wildlife, states: "Human activities in or near wildlife habitat may cause some animals to alter their activity and feeding patterns. Although such alterations may seem relatively harmless at the time to the casual observer, they may have non-trivial consequences for the animal. For example, stress that results from human disturbance may lead to increased susceptibility to disease, reduced reproductive output in some species, or abandonment of the area temporarily or permanently."

The handbook continues: "When surprised or threatened, wildlife react in a number of ways, occasionally "playing possum" or assuming a defensive posture, but more often fleeing. Active responses to human disturbance are typified by the animal's running or taking flight in order to escape. This sort of response is associated with a number of profound physiological adjustments, such as increased heart and respiration rates, elevated blood sugar, increased blood flow, and increased body temperature

-- in other words, stress. Energetic costs associated with an active response to human disturbance may have serious consequences for animals. This is especially true during critical times of the year, such as the postnatal period for mammals or the breeding period for birds, when an animal's energy reserves are already depleted and further stress may result in diminished reproductive output. For birds, disturbance may result in slower growth or premature fledgling for nestlings, and in nest evacuation or abandonment by the parents. Even if the parents eventually return to the nest, the eggs or young may be lost to predators in their absence."

Last year, the Ecological Society of America reported on research conducted by wildlife biologists Robert Steidl of the University of Arizona and Robert Anthony of Oregon State University about the effects of human visitations to the Gulkana National Wild River in Alaska upon resident bald eagles. The article reported: "Adult eagles decreased some activities by as much as 59% per day when humans were nearby. In addition, the percentage of time that they left their nesting area unattended increased by 24%. . . . [W]hen humans were near the nests, the number of feeding bouts at the nest decreased by 20% per day. Further, the amount of prey consumed by the eagles decreased by an average of 29% per day."

The Wildlands Design

A modern approach to minimize human disturbance of wildlife is the Wildlands Design, whereby wildlife managers designate a core habitat area where human visitation and activities are severely restricted. A buffer area, where people may engage in customary wilderness recreation, surrounds the core. Some managers even design a layer of concentric buffers, with progressively greater human presence and activity in the outer layers. Where feasible, wildlife corridors may link otherwise isolated habitat areas.

The Human-free Habitat Resolution

The resolution presented in this month’s agenda carries the Wildlands Design one step further by proposing that the Sierra Club advance the idea that some area or areas be designated as completely off limits to people.

We are not proposing any particular area or habitat size, but rather, the concept. Once before the public, the proposal may spark a serious discussion within society and among wildlife professionals. Such discussion may raise awareness in people about the particular needs of wildlife and may lead people to understand the perspective of other species, as those beings struggle to live in an increasingly human-dominated world. It may also lead to improvements in the design and regulations pertaining to existing and planned core habitat areas.

The proposal is experimental and need not materially restrict existing recreational opportunities.

Some Requirements


We recognize that there may be a serious enforcement issue. The forbidden attracts. Moreover, poachers may see opportunities, and others may view any off-limit area as a haven for illegal activities.

Selecting habitats in relatively inaccessible areas or providing for remote oversight might help reduce violations, but neither of those is a perfect solution.


Despite the enforcement problem, which others may solve, expected political opposition, and other potential issues, the Chapter Wildlife Committee believes that the resolution merits adoption by the Chapter and the Club. The San Francisco Bay Chapter adopted a resolution with similar language. The resolution we present here is compatible with the Club’s mission, guidelines, and policies. For example, section 3(a) of the Sierra Club’s Wildlife and Native Plants Policy states:

"Within natural ecosystems, the Sierra Club believes natural diversity and abundance of wildlife and native plants should be ensured by means that involve a minimum of overt human interference."

Thus, the Wildlife Committee urges the Loma Prieta Conservation Committee to adopt the resolution.