David Cole, Aldo Leopold Wilderness Research Institute; and Steven Boutcher,Washington Office, Wilderness & Wild and Scenic Rivers Staff
An archived version of this topic paper is available.
More than 100 million acres (42,000 ha) of public land--about 5% of the United States--has been set aside as wilderness, to protect valued landscapes and their biological and/or physical attributes in a state that is generally free from human development, disturbance, and manipulation (1). While the discussion that follows is most germane to Congressionally designated wilderness, much of it is applicable to other types of protected areas. Although climate change threatens many of the values for which wilderness areas were designated (2), wilderness can often serve as a central component of a comprehensive response to climate change (3). In particular, wilderness contributes to climate change adaptation through:
- Understanding ecological systems. Wilderness areas, like all lands, are affected by a host of anthropogenic influences, from fire suppression to air pollution. However, these influences are relatively less pronounced in wilderness and hands-off management is the norm. Therefore, wilderness provides one of the best baselines for understanding how ecological systems, from grassland to alpine tundra, function and respond to a changing climate (4).
- Sustaining biodiversity. The large scale and long-term protection of wilderness provides one of the best and most economical opportunities to sustain biodiversity and the dynamism of ecosystems in the face of climate change (5). The legal mandate to protect "the community of life," particularly in wilderness, allows Forest Service wilderness to protect entire ecosystems and the wide range of environmental gradients necessary for species migration, dispersal, and viable populations as the climate changes.
- Connecting landscapes. Wilderness, more than any other land classification, provides the necessary connectivity across large landscapes so plant and animal species have the opportunity to move from one area to another under a changing climate (6).
- Providing ecosystem services. Wilderness provides many goods and services that benefit people in surrounding landscapes, and such ecosystem services will likely be increasingly important under a changing climate (7). For example, in the western states, more than 50% of the water supply comes from National Forest System land and most headwater watersheds are located in wilderness. Other examples of ecosystem services include flood mitigation and carbon sequestration.
- Fostering human-nature relationships. Wilderness provides one of the last reminders of the human connection to the natural world, with inspirational, therapeutic, spiritual, cultural, and psychological values that grow increasingly important in a world dominated by urbanization and anthropogenic climate change (8).
Wilderness landscapes and the biodiversity they harbor are largely a product of past climate change. What is different now is the pace of change and, more important, the fact that climate change is playing out across landscapes already affected by anthropogenic stressors-loss of top predators, pollution, invasive species, altered disturbance regimes, and land fragmentation (9). Although the specific details of climate change effects on wilderness landscapes remain uncertain and highly variable from place to place, climate change will make wilderness and protected area stewardship more difficult. It is already compromising the degree to which protected areas function as a refuge from the effects of expanding civilization. More specifically, climate change exacerbates a range of ecological problems including the effects of fragmentation on species that need to migrate (10), the prevalence of invasive species well-adapted to disturbance and climatic change (11), and unprecedented outbreaks of insects and disease (12).
Of particular importance to wilderness values and their stewardship are changes to water, fire and biodiversity conservation.
- Water. Climate change in western mountains is projected to decrease snow pack, increase winter flooding, and reduce summer stream flow, making it likely that critically important water supplies will decrease (13). Given this, the water that falls in wilderness headwaters will be increasingly important for surface and underground water recharge to municipal water systems, making protection of wilderness water quantity and quality particularly important.
- Fire. Although climate change effects on precipitation will be variable and are uncertain, warmer temperatures, reflected in longer growing seasons, drier soils and drier fuels have already been implicated in an increase in the frequency, intensity and size of wildfires (14). If the risk of catastrophic fire increases, it will be more important than ever to move beyond exclusive reliance on traditional fire suppression to fire management policies that better balance the short and long term risks associated with fire.
- Biodiversity conservation. Between 20% and 30% of plant and animal species are likely to be at an increased risk of extinction if increases in global average temperatures exceed 2.7 to 4.5° F (15). Species distributions will shift and this, along with climate-induced changes to the physical environment, will result in protected area ecosystems that differ substantially from those of the past. Modeling suggests that more than 40% of the protected areas in Canada will experience a change in biome type (16).
Options for Management
The first step in responding to climate change is to clarify protected area goals and purposes. In the past, goals have stressed natural conditions-usually considered to be either those that would exist in the absence of modern, technological humans or past conditions within a range of historic variability (17). Moreover, wilderness managers have always been encouraged to take a "hands-off" approach to managing ecosystems (1). Although these goals were once considered to be congruent, it is now clear that they are not (17). There is an urgent need to redefine, in the context of climate change, what it means to maintain and protect natural conditions. Protected area managers must carefully articulate management objectives, leading them to good decisions about whether or not to intervene in ecological processes and, if they do intervene, what the desired outcomes of interventions are. They must decide whether goals should focus on function and process or on composition and structure and how diverse goals should be (17, 18).
Depending on goals and objectives, adaptation strategies can focus on restraint (leaving some places alone), resisting change and restoring past conditions, enhancing resilience, or facilitating change (19). Managing under uncertainty will require strategies such as hedging bets and tools such as adaptive management and scenario planning (20). Managing in the face of climate change will require a toolbox of approaches, including both short-term and long-term strategies (21, 22, 23, 24).
Near-term actions managers might consider include:
- Mitigate threats to resources;
- Maintain natural disturbance dynamics;
- Reduce landscape synchrony;
- Make aggressive but thoughtfully prioritized efforts to rescue highly sensitive species;
- Realign conditions with current, expected, or a range of possible future conditions;
- Relax genetic guidelines where risk is low and adaptive management can be implemented;
- Conserve refugia;
- Allow or actively assist migration;
- Protect highly endangered species ex situ.
Longer-term, large-scale actions to consider include:
- Promote landscape connectivity;
- Manage the matrix;
- Promote diversity and redundancy;
- Incorporate uncertainty and the likelihood of surprise into planning and management;
- Prioritize and practice triage;
- Increase interagency cooperation;
- Increase flexibility and the capacity to adapt through learning.