Framing management of social-ecological systems in terms of the cost of failure: the Sierra Nevada, USA as a case study

Managing complex social-ecological systems in an era of rapid climate change and changing human pressures represents a major challenge in sustainability science. The Sierra Nevada, USA is a large social-ecological system facing a tipping point that could result in major ecosystem changes. A century of fire suppression and climate change have set the stage for mega-disturbances that threaten biodiversity, human life and values, ecosystem services, and forest persistence. Stakeholders face multidimensional and often contentious trade-offs with costs and benefits that can be mismatched in space and time. If compromises cannot be reached, the status quo is likely to continue, resulting in the conversion of large portions of a 100 000 km2 predominately mixed-conifer forest ecosystem to a chaparral-dominated ecosystem. We describe the outcomes of a continuation of the ecological status quo on biodiversity, cultural history, fire management, recreational value, and climate control, including indirect effects on water and food security and recreation. The social-ecological ramifications of such a future are undesirable for most stakeholders. Therefore, we contend that forest management conflicts should be framed in terms of the cost of failure of negotiations among stakeholders. Specifically, negotiations may benefit from (1) stakeholders quantifying their definitions of success and failure, (2) quantification of trade-offs and recognition of their multidimensionality, and (3) allowing for solutions that are heterogeneous in space and time. This approach may help stakeholders navigate the wicked problem of managing Sierra Nevada forests and other complex social-ecological systems.

Sustainable use of natural resources is predicated on management that recognizes the fundamental interconnectedness of 'human' and 'natural' systems as a cohesive social-ecological system (Berkes and Folke 2000). Rapidly growing human populations have increased demand for a wide range of ecosystem services, so improving the sustainability of society's use of these services has become a central goal in the management of social-ecological systems (Clark and Dickson 2003, Rodríguez et al 2006, Wu 2013. However, the difficulty of identifying salient ecosystem services and stakeholders (Rodríguez et al 2006), the role of climate change in altering ecosystem function (Mooney et al 2009), and the large spatial scale (Wu 2013) and complexity (Liu et al 2007) of many social-ecological systems complicate the already-difficult challenge of sustainable ecosystem management (Defries and Nagendra 2017).
One such system is the Sierra Nevada, a complex social-ecological landscape that includes ∼100 000 km 2 of primarily forested mountains in the US state of California (SNC 2019). Sierra Nevada forests are home to >600 000 people as well as thousands of species of plants and wildlife, many of which are endemic to the region (Murphy and Stine 2004). Via its snowpack, the Sierra Nevada provides water for nationally important agricultural production and tens of millions of people in California (Klausmeyer andFitzgerald 2012, SNC 2019). Sierra Nevada forests also provide timber resources, cultural and recreational value, and climate control via carbon storage, among other ecosystem services . With the human population in California expected to grow by 25%-30% by 2040 (PPIC 2019), continued provisioning of ecosystem services and resources is a priority for public officials and land managers. Mismanagement of this social-ecological system therefore bears widereaching and potentially irreversible consequences for humans and nature.
Qualitative projection of the Sierra Nevada ecological status quo and its consequences Over the next several decades, a continuation of this altered disturbance regime could result in the conversion of mixed-conifer forest to a chaparral-dominated ecosystem (table 1). Such a scenario is a possible and perhaps even likely outcome of a continuation of the status quo in the Sierra Nevada , which would likely impair the provisioning of ecosystem services required to sustain the region's existing and projected human population. Below we detail the potential consequences of ecosystem type conversion (from forests to a chaparral-dominated ecosystem) in the Sierra Nevada on (i) biodiversity, (ii) cultural history, (iii) fire and smoke management, (iv) recreational value, and (v) climate control, which could trigger further indirect effects on water and food security and recreation.

Biodiversity
Extensive decline of Sierra Nevada forests would raise the possibility of widespread extinction events. The California Floristic Province is a global biodiversity hotspot (Myers et al 2000), and Sierra Nevada forests are a hotspot of plant endemism within that region (Thorne et al 2009). Loss of forest cover is expected to exacerbate the existing threat of climate change to those species (Loarie et al 2008). Iconic species like the

Cultural history
The transformation of the Sierra Nevada forest ecosystem would result in the loss of cultural ecosystem services and sociocultural history. Drastic ecological changes could be detrimental to indigenous communities whose intimate relationships with the Sierra Nevada ecosystem date back at least 11 000 years (Safford and Stevens 2017). The Sierra Nevada also imbues the works of iconic American artists John Muir, Ansel Adams, and Gary Snyder, and has influenced many others. Even substantial change short of total ecological transformation would be sufficient to radically change the human experience of the Sierra Nevada. Just as we are left with Muir's words and Albert Bierstadt's sketches as an elegy to the Hetch Hetchy Valley, we could eventually be left with mere memories of the Sierra Nevada humankind has known for many millennia. , including programs that seek to reduce fuels and prevent severe wildfires from occurring. In 2018, the California Department of Forestry and Fire Protection budgeted $434 million for fire suppression, but spent over $670 million, and private insurance claims exceeded $845 million (Shoot 2018). Continued increases in severe wildfire activity and continued growth of the wildland-urban interface will further increase firefighting costs. Large, severe fires also pose public health risks via air pollution. Smoke exposure from wildfire has been associated with increased asthma attacks (

Recreational value
The recreational value of Sierra Nevada forests and alpine areas is exceptional, and is increasing. Yosemite is the country's fifth-most visited national park, and annual visitation has exceeded 2 million since 1967, 3 million since 1987, and 4 million since 2015 (NPS 2018

Climate control and cascading effects
If current trends in forest loss due to wildfire and ongoing climate change continue, Sierra Nevada forests may become a carbon source and create a positive feedback with cascading effects (Liang et al 2017a(Liang et al , 2017b. The Sierra Nevada will be influenced by climate change whether it is a carbon source or sink, but if it becomes a carbon source, the acceleration of climate change would have important regional ramifications. Loss of snowpack and forest cover would have wide-reaching agricultural and food security implications for California and the United States. It would threaten California's $50 billion agricultural industry, which depends on water provisioning from the Sierra Nevada, and which provides one third of the country's vegetables and two thirds of its fruit and nuts (CDFA 2018). The Sierra Nevada provides clean water for 25 million people (Klausmeyer and Fitzgerald 2012), and demand for clean water will only rise with a growing human population. Large, severe wildfires can introduce pulses of sedimentation into affected watersheds, which can result in millions of dollars of damages to water treatment facilities (Edelson and Hertslet 2019). These outcomes are plausible consequences of a continuation of current trends in Sierra Nevada forests. The social-ecological ramifications of such a future are expected to be undesirable for most stakeholders (table 2), and prompt, effective forest management is likely necessary to avoid it.

Multidimensional trade-offs and spatiotemporal mismatches
In their attempts to avoid that future, stakeholders face multidimensional and often contentious trade-offs (table 2) whose costs and benefits can be mismatched in space and time and are often scale-dependent (Cumming et al 2013(Cumming et al , 2006. Following Euro-American genocide of indigenous populations and a century of highly effective fire suppression (Taylor et al 2016), reducing accumulated forest fuels has become a major conservation conflict in the management of Sierra Nevada forests. Tools for fuel reduction include mechanical thinning (i.e. selective removal of smaller and medium-sized trees), mastication, and increased use of prescribed and managed fire, each of which can be applied in a variety of ways and combined with other approaches Managed wildfires and prescribed fires (collectively 'managed fires') have lower emissions than escaped or unplanned fires (collectively 'unmanaged fires') (Ahuja 2006), but air quality regulations constrain the use of managed fires, which can ultimately result in the more intense effects of unmanaged fires . Managers face the difficult choice of imposing lower present-day emissions on California residents by managing and even starting fires, or awaiting greater future emissions when larger, unplanned fires occur. A retrospective analysis suggests that prescribed fire may result in better health outcomes for children in California than unmanaged fires (Prunicki et al 2019). There are also legal and financial risks associated with managed fire, because the risk of damage from escaped fires can be minimized but not eliminated. For example, a jury found the Nevada Division of Forestry guilty of gross negligence after a prescribed burn destroyed 23 homes worth an average of $1.4 million each (Hidalgo 2018). This risk is increasing because residential development in the Sierra Nevada is projected to grow (Mann et al 2014). Managed fires may reduce the risk of highly destructive megafires (e.g. damages related to the 2014 King Fire exceeded $60 million; Vives 2016), but entail legal exposure that simply waiting and hoping currently does not.
The Sierra Nevada is the core range of the declining California spotted owl, and decisions related to fire management and other complex, interconnected processes will play an important role in determining its long-term viability. Large, severe fires lead to population declines through loss of nesting habitat (Jones et al 2016), but, as noted above, fuel reduction treatments may also exert negative population effects through habitat alteration (Stephens et al 2014). However, there is increasing evidence that the potential longterm benefits of treatment (reducing fire-related habitat loss) may exceed short term costs to owls from habitat alteration, meaning that owl conservation and ecosystem restoration might be compatible , Wood et al 2018, Jones 2019. Though largetree logging has mostly ended on public land in the Sierra Nevada, the absence of those trees may have contributed to ongoing spotted owl population declines (Jones et al 2018), illustrating the temporal mismatch between decision and consequence. Those mismatches are further illustrated by the manner in which the differential forest management histories on private lands (intensive timber extraction), national forests (large tree logging and fire suppression), and national parks (limited logging history and increased use of fire) in the Sierra Nevada have mediated spotted owl territory survival via its influence on their small mammal prey (Hobart et al 2019b). Importantly, the Sierra Nevada population of the California spotted owl is threatened by other processes, notably (i) a rapidly growing barred owl population (Wood et al in review) that could cause further spotted owl population declines through conspecific aggression and competition (Yackulic et al 2019), and (ii) the possibility of widespread and persistent environmental toxicity via anticoagulant rodenticides that can cause direct An important consequence of the complexity of the social-ecological system that is the modern Sierra Nevada is the propensity for the ramifications of forest management decisions to ripple in space and time. Continued fire suppression may yield short-term benefits in terms of avoiding property damage and legal exposure for management agencies, but result in longterm costs to residents, insurers, and other agencies because continued fuel accumulation is likely to lead to even larger, severe fires that are difficult to control . The managed fires that may help prevent the Sierra Nevada from becoming a carbon sink bear costs for California residents in terms of air quality (albeit potentially less severe costs than those posed by wildfire; see Prunicki et al 2019) and benefits for residents of the United States as a whole in terms of sustained agricultural productivity (CDFA 2018). Individually, these examples represent conservation conflicts, or situations in which stakeholders with differing levels of power disagree about conservation objectives (Thomas 1992, Redpath et al 2013. Together, this network of stakeholders whose goals and desired outcomes are linked asymmetrically in space and time makes forest ecosystem management in the Sierra Nevada a 'wicked problem' (Defries and Nagendra 2017, Mason et al 2018). As a result, there is a serious risk that endless negotiation and protracted litigation will result in gridlock (e.g. Gutiérrez et al 2015) and thus a continuation of the status quo towards a nearly universally undesirable future.

Framing management debates in terms of the cost of failure
We contend that forest management debates in the Sierra Nevada should be framed in terms of the cost of failure of negotiations among stakeholders. Such a failure could result in the continuation of the status quo, and thus the widespread conversion of Sierra Nevada forests to a chaparral-dominated ecosystem which could result in the consequences we described above. This may serve as a potent and perhaps ominous reminder of what is at stake. However, it should not be used as a cudgel to expedite the implementation of policies that have not been properly evaluated. We outline three specific actions that can help keep the cost of failure appropriately present in negotiations.
First, we believe negotiations can be improved if stakeholders explicitly define the outcomes they are trying to achieve (success), the outcomes they are trying to avoid (failure), and the acceptable space between (potential compromises) (table 2). The important distinction here is between failure and the minimum acceptable outcome, as this may highlight underlying commonalities between groups. It is our understanding that the widespread conversion of Sierra Nevada forests to a chaparral-dominated ecosystem is likely to be a widely-shared definition of failure, and both the likelihood that such a definition is shared and the broad spatiotemporal scales it implies may be valuable in framing management debates. Identifying commonalities among stakeholders may help ameliorate transactional or even confrontational relationships. Sharing one's range of acceptable outcomes may expedite negotiations by rapidly identifying potential compromises and specific points of contention. However, revealing one's minimum acceptable outcome(s) raises the possibility that other parties will immediately negotiate towards that outcome, particularly if the debate is perceived as a zero-sum game.
This approach is therefore predicated on significant institutional trust between stakeholder groups and on individual rapport between their representatives. Developing those relationships is not easy or fast, but can lead to novel solutions. For example, in conservation conflicts surrounding the spotted owl, the relationship between academic researchers and the timber industry has historically had adversarial undertones. However, in the Sierra Nevada, the two groups recently began collaborating and were able to document previously unknown elements of California spotted owl resource use and population ecology, thus identifying promising new pathways in the conservation of that subspecies (Hobart et al 2019a, 2019b, Atuo et al 2019). Unsurprisingly, the absence of trust can impede the management process. The erosion of trust can be an ongoing process, as can occur if stakeholders engage in agenda-driven science, defined as the misuse of the scientific process or violation of scientific norms to advance a particular management outcome . Parties engaging in agenda-driven science compromise their own credibility (thus undermining their own objectives) and impede the accurate evaluation of management proposals by adding potentially unsound information to the scientific literature. The absence of trust can also be a residual outcome of historical events. For example, the Quincy Library Group, a group of northern Sierra Nevada stakeholders engaged in a congressionally-mandated collaboration with the USFS to develop forest management policy, was notably incomplete because some environmentalists refused to participate because a major timber industry group was participating (Gutiérrez et al 2015, Cheng et al 2016. This illustrates the potentially generational effects of broken trust: if individual representatives of stakeholder groups feel their trust has been betrayed, they may be unlikely to engage in future discussions, even if the personnel and institutional culture at the aggrieving groups have changed. Second, relevant trade-offs should be quantified and potential multidimensionality should be explored and stated. This is a natural extension of defining a range of acceptable outcomes, because it allows for the explicit testing of the feasibility of proposed solutions. Such efforts will be facilitated by studies conducted at spatiotemporal scales sufficient to capture the relevant ecological processes (e.g. Wiens 1989, Wood et al 2019. Incorporating the multidimensionality of many, if not most, potential management actions in the Sierra Nevada would be an important acknowledgment of the inherent complexity of the social-ecological system. It could also improve negotiations: the more multifaceted a debate, the less it can be conceived as a zero-sum game, and the more parties may be able reach mutually beneficial (or at least tolerable) solutions.
Empirical testing via experimentation is a powerful way to assess potential trade-offs. For example, a 10-year, full-factorial experiment with three levels of forest thinning and two levels of burning quantified the trade-offs between CO 2 emissions generated by fire, generated and averted by forest management activities, and sequestered by forest growth (Wiechmann et al 2015). When experimentation is not feasible, simulations have proven valuable. Spotted owl protected activity centers (PACs) are often considered an impediment to fuel reduction treatments in the Sierra Nevada, but fire models including and excluding PACs from simulated treatments suggested that the two can be compatible (Dow et al 2016). Subsequently, owl population projections quantified the relationships between owl population change and treatment frequency and extent if hypothetical fuel reduction treatments of different intensities were conducted in PACs that had been vacant for different durations (Wood et al 2018). We acknowledge that funding, executing, and sustaining ecological experiments and long-term studies is very expensive and notoriously difficult. For example, an insufficiently large spotted owl population and delays in implementing fuel treatments across the landscape necessitated substantial alteration of a planned before-after control-impact design of the spotted owl/fuel reduction treatment study component of the Sierra Nevada Adaptive Management Project (Peery et al 2014). Quantifying management trade-offs and identifying multidimensionality with an ideal experimental design will not always be possible, and when it is the cost may be daunting. Yet such work is integral to the evaluation of potentially contentious management decisions, and those costs should be considered in the context of the potential costs of failing to develop sound management. This mindset will not obviate budgetary constraints, but it may place them in an appropriate context. Third, consistent with the multidimensionality of many forest management trade-offs, stakeholders should allow for solutions that are heterogeneous in space and time. Solutions that fail to account for the complexity of the problems they purport to solve are unlikely to be fully successful. Particularly in large ecosystems like Sierra Nevada forests-entailing tens of thousands of square kilometers of forest spanning four degrees of latitude and a 4000 m elevational gradient -substantial variation is likely necessary to accommodate the range of conditions (North 2012). From a negotiating perspective, heterogeneous solutions may facilitate the creation of mutually acceptable solutions by providing more axes for compromise. From an implementation perspective, such solutions are likely to be expensive, and there may be disagreement among stakeholders regarding the relevance of some costs. For example, a county-level environmental NGO and the USFS may be mandated to weigh the potential effects of a forest management plan on national food production via changes in California's hydrology quite differently. To whom such costs are relevant and whether they can be internalized in formal cost/benefit analyses is difficult to determine. In light of such complexities and of increasing budgetary constraints, we suggest again that the costs of potentially complex and heterogeneous management plans be compared not only to those of simpler plans, but also, to the greatest extent possible, to the potential costs of the consequences of not employing the optimal management plan.
The constraints that California spotted owl habitat conservation may impose on ecosystem restoration planning illustrate both the complexity and promise of multidimensional trade-offs. Although California spotted owls are primarily associated with old-growth forest conditions, the strength of forest associations and relative importance of different forest types varies across their range , Jones et al 2018. Likewise, the level of ecological departure from historical conditions varies across the Sierra Nevada (North 2012). Therefore, different types and intensities of fuel reduction/restoration treatments are likely necessary in different places even though they are generally necessary across the range, and the subsequent effects of fuel treatments on spotted owl populations will likely vary in direction (positive, negative, or neutral effects) and magnitude (weak or strong effects) and will also vary in space and time (Jones 2019). This variation may allow for more flexible and heterogeneous solutions to landscape-scale fuel treatments. At finer scales (~4 ha), heterogeneity in the application of fuel reduction treatments can also allow flying squirrels-a key prey item for spotted owls in Sierra Nevada national forests (Hobart et al 2019b)-to move in response to loss of preferred habitat such that the population density does not change at the scale of an individual spotted owl territory (∼400 ha) (Sollmann et al 2016). Communicating these necessarily complex solutions to stakeholders and the public, as well as translating these solutions into on-the-ground action, is likely to be challenging. The addition of communication professionals to science and management teams could be beneficial (Enquist et al 2017).
There is considerable evidence that Sierra Nevada forests face a tipping point, and that without potentially substantial management they could be drastically reduced in extent. The many cascading consequences of such change are nearly universally undesirable (tables 1 and 2). Yet managing this social-ecological system entails the navigation of multidimensional trade-offs whose complexity and spatiotemporal asymmetry can impede the implementation of solutions that could help avert that future. Our three proposals, (i) explicitly defining success, failure, and a range of acceptable outcomes, (ii) quantifying tradeoffs and acknowledging their multidimensionality, and (iii) developing solutions that are heterogeneous in space and time, incorporate the social-ecological realities of the Sierra Nevada and may help improve negotiations of forest management policy by keeping the steep cost of failure appropriately present. This may help urge stakeholders towards the development of solutions to the wicked problem of managing Sierra Nevada forests and other social-ecological systems.