Options for National Parks and Reserves for Adapting to Climate Change

Systematic and repeated characterization of potential climate change effects on resources is important for prioritizing where to focus scarce time, money, and effort. Characterization begins with a broad understanding of natural resources and their drivers, and can be accomplished through summaries of the literature, guided research, gatherings of experts, and workshops where scientists, managers, and the public discuss risks to resources. We caution against the tendency to insist on high-precision climate forecasts before undertaking this exercise. Detailed and site-specific climate forecasts may be helpful for specific applications, but general projections (e.g., warmer, greater variability in precipitation and temperature) may be sufficient for the initial stages of risk assessment. Subsequent iterations of the exercise can quantify resource risk in more detail according to the urgency and capacity of available resources to achieve desired management goals (Millar and others 2007). Not all resources will respond negatively or rapidly.

Assessment of risk requires explicit consideration of where thresholds lie and how crossing thresholds will affect valued species, communities, ecosystem processes, and their interactions. An ecological threshold has been defined as an abrupt or relatively rapid change in an ecosystem quality, property, or phenomenon (Groffman and others 2006). Climate change provides the impetus to identify not only societally acceptable versus unacceptable change, but controllable versus uncontrollable change. Some threshold concepts, including critical loads, are already used by national parks in the United States and Europe. A critical load is the value of atmospheric pollution deposition below which there is no discernable ecological effect (Porter and Johnson 2007). Effects of crossing climate change-related thresholds might include extirpation or extinction of species due to loss of climate envelopes, changes in fire regimes, or expansion of non-native invasive species (McKenzie and others 2004; Williams and others 2007).

Reference conditions describe the standard or benchmark against which current or future conditions can be compared (Stoddard and others 2006). Reference conditions can define an environmental condition in the absence of human disturbance, as suggested by Stoddard and others (2006). Reference conditions can also be more arbitrarily defined according the specific mission and goals of a park or reserve.

Why consider the reference condition when it may be unrecoverable in new climates? An established reference condition could be useful in considering adaptations to climate change in at least two ways. If the reference condition provides greater opportunity for species or populations to adapt to changing climate, then it offers a goal for protection or restoration. For example, removing migration barriers or restoring natural flow regimes to some rivers could allow cold water fishes to find suitable thermal conditions. Enlarging protected areas, as was recently accomplished by the Great Barrier Reef Marine Park in Australia, may provide refugia for coral reef species currently experiencing increased bleaching events that are relatively safe from other human pressures (Olsson and others 2008). Alternatively, if the reference condition is highly dependent on past climate conditions, knowledge that the conditions that produced the reference state are irretrievable can reinforce the need for adaptation to new conditions. Historical or paleohistorical records can reveal whether current species assemblages have been present for centuries to millennia, whether they are adapted to current conditions, or whether they are relict, persisting through biological inertia (Willis and Birks 2006). Scientific evidence that past and highly valued conditions are no longer attainable may provide the incentive to plan for ecosystems that are sustainable under future conditions (Choi 2007).

Many national parks and reserves monitor indicators of change. Are robust indicators measured at the appropriate frequencies for detecting and then managing climate-caused change? Recurring review of what is measured and why, aided with insight from experts or the scientific literature, can help ensure that climate change effects on resources designated as high priority (see section “Prioritizing Resources and Processes at Risk”, above) do not go undetected. Useful indicators are understandable to multiple audiences, including scientists, policy makers, managers and the public; they show status over time. There should be a clear, transparent scientific basis both for assigning a given condition to the indicator or drawing inference from the condition of the indicator to the phenomenon for which it serves as a surrogate, and for triggering a management activity (Harwell and others 1999).

Assessment of the effects of climate change involves tracking the indicators and their major drivers to detect trends, previously identified thresholds, or deviation away from an established reference condition. The understanding gained from studying past ranges of variability will be the essential starting point for projecting ecosystem behavior under possible future climates (Milly and others 2008) and initiating management intervention in advance of an anticipated but undesired change. Simulation and statistical models that are invaluable tools for forecasting need to be parameterized with or tested against physical and biological information that are often the same indicators used to assess existing responses to change. It is important, therefore, to consider data requirements for models when choosing which environmental attributes to monitor.

There are at least three different categories of climate change effects, each associated with a different level of uncertainty: foreseeable changes, imaginable changes, and unknown and therefore surprising changes. Projections of climate change effects are generally accepted if changes are generally understood and accumulating evidence continues to sustain the projections. For instance, there is high confidence that atmospheric carbon dioxide concentrations will increase, sea levels will rise, snow packs across most of North America will shrink, global temperature will increase, fire seasons will become longer and more severe, and the severity of storms will increase (IPCC 2007). We refer to a given change as foreseeable if there is a fairly robust model (either conceptual or quantitative) describing relationships among system components and drivers, and if there are sufficient theory, data, and understanding to develop credible projections. While the magnitude or timing of foreseeable changes cannot be projected precisely, in most regions we can estimate the direction and possible range of some future conditions. For example, a 40-year record shows that snow is melting increasingly earlier in the spring in the northeastern United States and montane western United States (Stewart and others 2005; Hodgkins and Dudley 2006). There is a strong understanding from the physical sciences of why the timing of snowmelt is likely to change in regions with winter and spring temperatures between−3 and 0°C as the climate warms (Knowles and others 2006).

Foreseeable changes are sufficiently certain to begin planning to address the effects of earlier snowmelt. Plans could include establishing or protecting refugia for valued aquatic organisms at risk at higher elevations or latitudes, removing barriers to natural species migrations, protecting multiple populations as a hedging strategy to reduce overall risk, or restoring riparian vegetation to shade river reaches. As the risk of fire increases, it might be appropriate to consider moving infrastructure out of fire-prone areas and restricting visitor access to fire-prone areas during fire seasons to lower the incidence of accidental fires. Many parks, such as Yosemite National Park, have been managing fuels and fire for decades, and have extensive prescriptive documents that describe where and how to manage in specific locations (Final Yosemite Fire Management Plan 2004). Continued applicability of methods that have been effective in the past, however, requires regular review of prescriptive methods because, as stated above, historic ranges of variability in natural disturbance cycles may not be appropriate targets in a different climate.

The second category of climate change includes changes that are known or imaginable, but whose effects are difficult to predict with certainty. During the warm drought of the early 2000s, extraordinary levels of forest mortality affected Bandelier National Monument in the Jemez Mountains of northern New Mexico (Allen 2007). Similar forest dieback had occurred in the region in the 1950s, when the lower extent of the ponderosa pine zone in Bandelier National Monument retreated upslope by as much as 2 km in less than five years in response to severe drought and an associated outbreak of bark beetles (Allen and Breshears 1998; Allen 2007). Scientists cannot yet model species-specific tree mortality thresholds in response to climate stress on real landscapes (McDowell and others 2008; Purves and Pacala 2008), making it difficult to project when such extensive, rapid ecological shifts will occur. Planning for these types of rare but major events requires that societal mechanisms be put in place to reduce the damage they cause. Mechanisms could include erecting physical barriers to minimize erosion that may occur given forest dieback, removing infrastructure from river corridors to minimize flood damage, maintaining corridors for species migration, or collecting and storing native seeds.

The third category of climate change is unknown or unknowable changes that have not previously been experienced by humans. Nonlinear interactions among system components and drivers can lead to surprise (Burkett and others 2005). Perhaps the greatest uncertainties in projecting climate change and its effects are associated with the interaction of climate change and other human activities. Novel ecosystems may emerge in response to the synergistic and cumulative interactions among multiple system components and stressors, such as new barriers or pathways to species movement, disruption of nutrient cycles, or the emergence of new diseases (Hobbs and others 2006).

A recent study notes the frequency of ecological surprises and attributes the occurrence at least partly to natural system complexity (Doak and others 2008). National parks and reserves are complex systems within complex landscapes. Doak and others (2008) suggest complexity and surprises reinforce the need for management plans that are highly precautionary, rather than plans that assume specific management actions will have specific outcomes. For example, the intentional introduction of a freshwater shrimp (Mysis relicta) to Flathead Lake, Montana, and other lakes in the western United States lakes with the intent of increasing salmon production resulted in substantial reductions in the abundance of native fishes and fish consumers such as bald eagles. Not only was shrimp behavior incompatible with the feeding strategy of salmon, but the shrimp rapidly consumed the zooplankton that had been a major food source for salmon (Stanford and Ellis 2002).

The two major factors that influence selection of strategies for managing complex systems are the degree (and type) of uncertainty and the extent to which key ecological processes can be controlled (Fig. 1). Different strategic approaches (Fig. 1) are appropriate for different types of management and while not interchangeable, the lessons learned from application of one approach can inform the decisions on whether to employ the other approaches.

The uncertainties associated with projections of climate change and its effects are substantial. Failure may occur regardless of the intent to implement a “correct” action. We suggest that parks and reserves consider implementing human resource management policies that actively manage for uncertainty. These have been called “safe-to-fail” policies. This type of approach is employed in fields where uncertainty is actively managed through flexible designs that adjust to changing conditions, such as engineering systems (e.g., air traffic control or electric power distribution) (Neufville 2003). When applied to a natural resource management activity, safe-to-fail policies resemble adaptive management, because a safe-to-fail experiment or action is undertaken only where there is confidence that the system can recover from failure without irreversible damage to the targeted resource. A safe-to-fail policy for human resources (e.g., careers and livelihoods) emphasizes the cooperative relationship between supervisor and staff or between agencies and stakeholders. The uncertainty inherent in achieving desired future conditions or trajectories strongly argues against management “by the book.” Safe-to-fail human resource policies empower individuals to take reasoned management risks without concern for retribution. Although a culture of trust between front line managers and their supervisors already exists at smaller scales in many public and private organizations, it might need to be expanded and enhanced. Lack of communication, especially about the implications of uncertainty associated with resource management in a changing climate, can lead to distrust, and result in withdrawal of decision-making authority and the imposition of regulations. Guidelines that codify the intellectual process by which decisions are made, rather than the decisions themselves, can lead to more effective resource management under uncertainty. If supervisors and upper level managers are satisfied that decisions are being made in a logical thoughtful way, it may promote the culture of trust at all levels within agencies and bureaus.

Even highly reasoned actions have some potential to go awry, especially as climate changes. Although clearly not desired, failures provide opportunities for learning. Continued and expanded public education about the complexity of resource management, transparency in the decision-making process, frequent public updates on progress or setbacks, and internal agency efforts that promote trust and respect for professionals are all important methods for promoting more nuanced management efforts. Developing a culture of trust between public servants and their public will require all these techniques, and will be important, if not critical, to implementing practices to adapt to climate change.

All parks and reserves operate within codified guidelines that define the scope of management activities—both allowed and required—to meet agency missions. Often, however, the interpretation of guidelines can evolve, making it appropriate to revisit interpretations in relation to management for adapting to climate change. While resource management is implemented at individual parks and reserves, planning and support is provided at all management levels. A consistent top to bottom vision of how to incorporate climate change considerations into management could promote short- and long-term adaptation practices and a shared culture of trust. We use the U.S. National Park Service (NPS) guidelines to illustrate a history of flexible interpretation of policy in response to increased scientific understanding of ecological systems, public opinions, and desires, and new laws and administrative directives. Past flexibility can serve as a precedent for future climate change adaptation practices and policies.

The NPS operates under its original Organic Act of 1916 “to conserve the scenery and the natural and historic objects and the wild life therein and to provide for the enjoyment of the same in such manner and by such means as will leave them unimpaired for the enjoyment of future generations” (U.S. Congress 1916). The 1970 General Authorities Act and the 1978 “Redwood Amendment” to the Organic Act strengthened its conservation mission by clarifying that the “fundamental purpose” of the national park system is to conserve park resources and values. National parks also abide by guidelines of the Wilderness Act of 1964, the Wild and Scenic Rivers Act of 1968, the Clean Water Act of 1972, the Endangered Species Act of 1973, and the Clean Air Act of 1990.

Although its mission has remained mostly unchanged, the NPS has undergone substantial evolution in management philosophy since 1916. Prior to the 1960s, parks actively practiced fire suppression, aggressive wildlife management (e.g., culling some species and providing supplemental food to others), and application of pesticides to prevent irruptions of native insects. Development of ski slopes and golf courses within park boundaries was congruent with visitor enjoyment. During the 1960s, the Leopold Report on Wildlife Management in National Parks, the 1964 Wilderness Act, and the growth of the environmental movement ushered in a different management philosophy (Leopold 1963; Sellars 1997). Policies changed as managers began to consider natural controls on the size of wildlife populations. Some park managers closed ski lifts and golf courses, deciding that these uses were not congruent with their mission. Implementation of the Wilderness Act of 1964 restricted mechanized and many other activities in designated or proposed wilderness areas within parks.

National park status, often considered the most fundamental of mandates, is not necessarily conferred in perpetuity. Twenty-four units of the U.S. national park system either have been deauthorized or transferred to other management jurisdictions (National Park Service Bureau Historian 2006). Fifteen areas were transferred to other agencies because their national significance was marginal, and others were deauthorized because their location was inaccessible to the public. The management of five reservoirs was consigned to the Bureau of Reclamation (National Park Service 2003). Consider that Fossil Cycad National Monument in South Dakota, by contrast, was deauthorized by Congress in 1957 due to near-complete loss of the fossil resource as a result of collecting activity (National Park Service 1998).

This example illustrates that management policies have evolved in response to new knowledge or societal desires. Circumstances change, and to its great credit, the National Park Service has changed with them. Perceptions of what are appropriate management actions evolve in light of new knowledge. The precedent of incorporating new or different policies, particularly those informed by scientific understanding, will serve the National Park Service well in the face of accelerating climate change.

Complex ecological systems operate and change at multiple spatial and temporal scales. The scales at which ecological processes operate often will dictate the appropriate scales at which management institutions should be developed. Migratory bird management, for instance, requires international collaboration; ungulates and carnivores with large home ranges call for regional collaboration; marine preserves require cooperation among many stakeholders. All are examples where working solely within park or reserve boundaries will be ineffective. Similarly, preparation for rapid events such as floods will be managed quite differently than responses to climate impacts that occur over decades. Species may be able to move to locations with favorable climate and other environmental conditions over time if natural areas and open space remain connected. There are several examples of management of park resources within larger regional or ecosystem contexts. The Greater Yellowstone Coordinating Committee (http://​www.​gycd.​org) and the Southern Appalachian Man and the Biosphere (SAMAB; http://​www.​samab.​org/​) are building relationships across jurisdictional boundaries that will allow effective planning for species and processes to adapt to climate change. Olympic, Channel Islands, American Samoa, Everglades, Point Reyes, and other coastal parks cooperate with many other state and federal agencies in advising and managing national marine sanctuaries. These ecoregional consortia can serve as models for other park areas as they begin to address the multiple challenges that originate outside park boundaries.