Introduction

Efforts to integrate ecosystem services, or the benefits people receive from nature, into US federal land management policy and practice have increased over the last 5 years. The US Forest Service is required to address ecosystem services in management plans for national forests (Federal Register 2012). The National Park Service incorporated ecosystem services into management planning and made ecosystem services a key part of their 2011 Call to Action (Jarvis 2011). In the strongest commitment to date, a Presidential Memorandum was issued in October 2015, instructing federal agencies to incorporate ecosystem services into decision making, and requiring each agency to formalize a plan for doing so (Office of the President of the United States 2015).

This emphasis on ecosystem services at the federal level is consistent with the role mountain ecosystems play in the United Nations 2030 Agenda for Sustainable Development (UN 2015) and with UN sustainable development goals (UN 2017). For example, the UN's Sustainable Development Goal (SDG) 15.4 is to “By 2030, ensure the conservation of mountain ecosystems, including their biodiversity, in order to enhance their capacity to provide benefits that are essential for sustainable development.” Protection of water-related ecosystems, including mountains, is also a goal (6.6).

Ecosystem services from public lands in the US Northern and Middle Rocky Mountains are critical for neighboring communities. Major uses of water in the region include domestic and municipal water supply, industrial use, oil and gas development, recreational uses, and hydroelectric power production. Both “Old West” livelihoods like timber and grazing and “New West” lifestyles tied to outdoor recreation are part of the cultural heritage of the region. Although their relative economic importance has declined in recent decades, timber and livestock grazing are important economic forces in the Rocky Mountains. Forest products make up about 23% of direct manufacturing employment in Montana (McIver et al 2013), and public lands are an important source of forage for ranchers, both as primary places to graze and as supplements to grazing on private lands (US GAO 2005). This region is also home to iconic landscapes such as Yellowstone National Park, Glacier National Park, and the Salmon River. More than 15 million people visit national forests and parks in the Greater Yellowstone Area and Glacier National Park area, and total annual expenditures by visitors in 2014 were more than US$ 800 million (according to National Visitor Use Monitoring Data; English et al 2001).

Climate change will likely result in increased occurrence of fire, insect outbreaks, and drought in the Rocky Mountains, driving ecosystem change and making the future provisioning of ecosystem services uncertain (Seidl et al 2016). Climate change will affect water availability and quality, human behavior and recreation, and provisioning of timber and forage (Mendelsohn and Markowski 2004; Mooney el al 2009; Montoya and Raffaelli 2010; Groffman et al 2014). Decreased quantity and quality of ecosystem services produced by public lands will affect human systems that rely on them, requiring communities to seek alternative means of providing these services or to change local economies and lifeways.

We describe here 2 recent science-based climate change vulnerability assessment and adaptation efforts for ecosystem services on federal lands in the US Northern and Middle Rocky Mountains. We specifically address the following questions: (1) How will climate change affect ecosystem services in the Northern and Middle Rocky Mountains? and (2) How can mountain ecosystems be managed to minimize negative impacts of climate change on ecosystem services and help meet UN SDGs 6 and 15? Although climate change affects every aspect of mountain ecosystems listed in the Millennium Ecosystem Assessment (2005), we focus here on aspects that affect community economic security and livelihoods, specifically water, timber, livestock grazing, and recreation (Figure 1).

FIGURE 1 

Major classes of forest services, as adapted from the Millennium Ecosystem Assessment (2005). Ecosystem services included in climate change vulnerability assessments described here are outlined in bold. We added grazing as a service provided by federal lands in the Northern Rockies.

Methods

Two science-management partnerships were developed to conduct climate change vulnerability assessments and determine adaptation options for US Forest Service and National Park Service lands in the Northern and Middle Rocky Mountains. Partnership locations included the Forest Service Northern and Intermountain Regions (Northern Rockies and Intermountain Adaptation Partnerships, respectively;  http://adaptation partners.org) (Figure 2). Vulnerability assessments covered hydrology, fisheries, forest and rangeland vegetation, ecological disturbance, and ecosystem services. Generally, assessments for ecosystem services built on assessments for the associated natural resources.

FIGURE 2 

Northern Rockies and Intermountain (Middle Rockies) adaptation partnership locations, with participating national forests and national parks. (Map by Jessica Halofsky)

Vulnerability assessments for ecosystem services were conducted in each of the study regions (Figure 2) by teams of scientists from the US Forest Service, other federal agencies, and universities. Assessments used the best available science and considered exposure, sensitivity, and adaptive capacity (sensu Parry et al 2007) for each ecosystem service (Halofsky et al 2017). To determine likely levels of exposure to climate change, or the degree of deviation in temperature and precipitation in the future compared to a historical period, downscaled general circulation model (GCM) climate projections, obtained from the Geo Data Portal at the US Geological Survey Center for Integrative Data Analytics, were summarized for the study areas (Joyce et al 2017). These data included projections from 34 GCMs under Representative Concentration Pathways 4.5 and 8.5 (van Vuuren et al 2011) from the Coupled Model Intercomparison Project 5, used in the Intergovernmental Panel on Climate Change Fifth Assessment Report (Stocker et al 2013). Climate projections were downscaled using the bias-correction and spatial disaggregation method (Maurer et al 2007).

Methods to assess climate change sensitivity differed by ecosystem service. In all cases, scientists reviewed published literature and available climate change impact model projections to determine sensitivity. Quantitative data were used when possible, but qualitative descriptions or proxy measures were often used. For timber and grazing, assessments drew from forest and rangeland vegetation vulnerability assessments (Keane et al 2017; Reeves et al 2017). Vegetation model output, such as that from the MC2 dynamic global vegetation model (Bachelet et al 2001) was used, where available. For water availability, the assessments were based on projections from the Variable Infiltration Capacity model (Liang et al 1994) and other analyses (Luce 2017). The recreation assessments were primarily qualitative assessments using a newly developed framework (Hand and Lawson 2017). To evaluate adaptive capacity, defined here as the institutional capability to modify management, decision-making, and policy to ensure sustainable production of ecosystem services, we evaluated the potential for ecosystems, agencies, and society to adjust to changing climate.

The vulnerability assessments were used as the basis for developing adaptation strategies and tactics in 10 workshops (Table 1); 5 workshops were conducted throughout each study region to capture geographic variation in resource condition and management issues. In the first part of the workshops, scientists presented vulnerability assessments for the resource areas (eg hydrology, vegetation, etc). Resource managers then separated into small groups by resource area and engaged in facilitated discussion to complete worksheets (adapted from Swanston and Janowiak 2012). In consultation with scientists, managers identified key vulnerabilities to climate change for each resource area and developed:

TABLE 1 

Number of resource managers, scientists, and agencies/organizations that participated in the 10 workshops as a part of the Northern Rockies Adaptation Partnership (Montana, North Dakota, and northern Idaho) and Intermountain Adaptation Partnership (Utah, Nevada, and southern Idaho). Participants had diverse backgrounds, with expertise in hydrology, soils, vegetation (botany, silviculture, forests, and rangelands), fire, entomology, wildlife, recreation, engineering, ecosystem services, and archaeology.

Managers identified options considered feasible given current regulations, funding, and personnel. Most of the resource managers participating in the workshops had 10–25 years of experience in their fields (Table 1), making them well qualified to provide strong expert judgements about appropriate management response to climate change (Halofsky and Peterson 2016). Adaptation options were also reviewed by teams of scientists and managers after the workshops to ensure scientific validity (Halofsky et al 2017).

Below, we summarize the results of the vulnerability assessments, as well as adaptation options developed in the science-management workshops, focusing on timber production, livestock grazing, water availability and quality, and recreation.

Results

Water availability and quality

Water yield, timing, and quality affect water supply for municipal and agricultural use, and all 3 will be affected by climate change in the Rocky Mountains. Water yield and timing are closely tied to snowpack in mountain landscapes, and warmer temperatures will likely result in reduced snowpack in the Rocky Mountains (Luce et al 2014). Earlier snowmelt will cause earlier stream runoff, and reduced snowpack will cause lower summer streamflows (Luce and Holden 2009). By the 2080s, the median flow date is expected to be over 20 days earlier in most locations in the Rocky Mountains, and summer flows are projected to decline by 20–40% in most locations (compared to 1977–2006 with moderate warming) (Luce 2017). Altered timing and quantity of summer flow are expected to cause shortages of surface water in locations where demand is high in the summer months (Figure 3). Municipal systems may experience increased treatment costs and greater dependence on groundwater intakes to meet demand.

FIGURE 3 

Drinking water vulnerability in national forests in the Intermountain Region under changing climate. The analysis utilized municipal drinking water intake locations and nearby spatial characteristics to identify drinking water vulnerability for the various users who depend on National Forest System lands within the region. Vulnerability is measured based on indicators of exposure, sensitivity, and adaptive capacity. The final components for each system were standardized for comparison to other water systems within the region. Exposure was measured according to projected changes in annual stream flow, summer stream flow, stream temperature, and runoff timing from downscaled climate models. Sensitivity and adaptive capacity were measured according to current sub-watershed land cover, use, conditions, and threats. (Analysis and map by Matt Elmer, Colorado State University)

Water quality may also be affected by changing climate in the Rocky Mountains. Stream temperatures are expected to increase in response to increased air temperature and lower summer flows (Isaak et al 2016). Extreme weather and a higher rain:snow ratio may increase runoff from agricultural fields and add pesticides and fertilizers to streams. In addition, increased number and severity of wildfires can accelerate sediment deposition in streams, lakes, and reservoirs (Benda et al 2003; Coombs and Melack 2013).

Public lands are a critical source of municipal water supplies. Increasing implementation of current practices that improve watershed function, such as restoring and protecting riparian systems and wetlands, reducing hazardous fuels in dry forests, and reducing erosion potential, will help ensure that public lands continue to provide high quality water to communities (Luce 2017). These tactics will be more effective if prioritized in high-value locations (near communities and reservoirs). Water storage can be increased by increasing American beaver populations, constructing wetlands, and decommissioning roads (Table 2). Reducing water use and increasing efficiency will also be increasingly important for maintaining adequate supplies. Federal agencies can demonstrate leadership in water conservation, conveying a positive image to local communities.

TABLE 2 

Summary of climate change vulnerabilities, adaptation strategies, and adaptation tactics for water quantity and quality in the Rocky Mountains.

Timber

With increased temperatures and atmospheric CO₂, the potential exists for increasing forest productivity (Aston 2010) and biomass accumulation (Lin et al 2010), which may lead to increases in timber production at higher elevations (Garcia-Gonzolo et al 2007; Keane et al 2017). Moisture limitations, ecological disturbances, and their interactions may reduce forest growth at low elevations (Littell et al 2013). Over decades, higher temperature and soil moisture deficits may cause the location of some desirable timber species to shift and in some cases to be more susceptible to root disease (Keane et al 2017).

Climate change may also increase wildfire area burned (Westerling et al 2006; Rocca et al 2014; Barbero et al 2015), drought severity (Littell et al 2016; Vose et al 2016), and insect outbreaks (Bentz et al 2010; Loehman et al 2017). These disturbances are often associated with significant tree mortality. Though harvests can increase in the short term through salvage of dead and dying trees, long-term timber availability is expected to decrease (Warziniack et al 2017). Warmer winters and associated freezing and thawing may increase forest road erosion and landslides, making winter harvest more difficult and expensive, and potentially reducing timber supply (Karl et al 2009). However, adaptation in US timber and wood product markets may offset potentially negative effects of climate change (Irland et al 2001).

Adaptation strategies for timber (Table 3) mainly focused on increasing resilience to changing conditions (Keane et al 2017). For example, many strategies and associated tactics focused on promoting productivity and vigor of existing forests to reduce susceptibility to stress from drought, insects, and wildfire. Current practices, including forest thinning and prescribed fire, were suggested as tools that could be increasingly used to reduce stress from multiple sources (Littell et al 2013). More novel approaches, such as promoting disturbance-resilient species and increasing species and genetic diversity through plantings, could also help increase resilience to changing climate (Dymond et al 2014) (Table 3). In the future, modifying tree-species seed zones and assisted migration could be used to help transition ecosystems to new climates (Halofsky and Peterson 2016).

TABLE 3 

Summary of climate change vulnerabilities and adaptation options for timber in the Rocky Mountains. (Table continued on next page.)

Livestock grazing

In the Northern Rocky Mountains, increased temperatures and growing season length are expected to increase net primary productivity in rangelands, particularly at higher elevations (Reeves et al 2014; Reeves et al 2017). Increased atmospheric CO₂ concentrations may also increase rangeland productivity by increasing water use efficiency (Izaurralde et al 2011; Polley et al 2013; Reeves et al 2014). However, in low-elevation, moisture-limited areas of the Northern and Middle Rockies, without significant increases in precipitation, increased temperatures will increase evaporative demand, reducing soil moisture and productivity (Polley et al 2013). Increased wildfire area burned and establishment of non-native species may also decrease rangeland productivity. For example, dominance of non-native annual grasses can create a positive feedback in which frequent fire leads to increased dominance of annual grasses, which create fuel conditions that facilitate more frequent fire (Chambers et al 2007). These conditions are exacerbated by wetter and warmer winters (Joyce et al 2017).

Adaptation strategies for grazing focused on increasing resilience of rangeland vegetation, primarily through current approaches to non-native species control and prevention. Demand for grazing on high-elevation national forest land may increase with warming. Federal land managers identified increasing flexibility in timing, duration, and intensity of authorized grazing as a tactic to prevent ecosystem degradation and allow ecosystems to transition to new conditions (Table 4). They also stressed the importance of developing a holistic approach to grazing management, taking ranchers' needs into consideration, and developing a collaborative relationship with range permittees that focuses on problem solving rather than rule enforcement.

TABLE 4 

Summary of climate change vulnerabilities and adaptation options for grazing in the Rocky Mountains.

Recreation

Warming temperatures in the Rocky Mountains will likely increase participation in outdoor recreation (Bowker et al 2013), with increases in warm-weather activities outweighing losses in winter activities (Loomis and Crespi 2004; Mendelsohn and Markowski 2004). Warming is expected to reduce season length and the likelihood of reliable winter recreation seasons. Lower elevations may become unsuitable for snow-based recreation because of warmer temperatures. High-elevation sites will likely experience more variability in season length (Hand and Lawson 2017).

In contrast, climate change is expected to lengthen the season for warm-weather activities as snow- and ice-free sites become accessible earlier, and temperatures are higher during the autumn and spring “shoulder” seasons (Hand and Lawson 2017). However, extreme summer temperatures can dampen participation during the hottest weeks of the year (Bowker et al 2012), shifting demand to cooler weeks or to alternative sites less exposed to extreme temperatures (eg lakes, reservoirs, and streams). Wildfire activity may reduce demand in some years because of degraded site desirability, impaired air quality from smoke, and limited site access. Recreation visits to sites with highly valued natural characteristics (eg glaciers and charismatic wildlife species) may also decrease in the future if the quality of those sites is threatened (Scott et al 2007). For example, fishing for cold-water species (eg salmon) is expected to decline with increased stream temperatures that threaten habitat (Jones et al 2013).

Adaptive capacity among recreationists is high because they can switch to alternative sites, alter the timing of visits, and alter capital investments (eg gear). The ability of federal managers to adjust recreation management to climate change is generally more limited. To provide sustainable recreation opportunities, it will be necessary to consider how infrastructure investments and maintenance of facilities align with changing ecological conditions and demands for recreation settings (Table 5). For winter recreation, recreation management can transition to shorter seasons and changing use patterns. Specifically, opportunities may exist to expand facilities where concentrated use increases, and options for snow-based recreation can be diversified to include more snow-making, additional ski lifts, and higher elevation runs. For warm-season recreation, a first step will be to conduct assessments to understand changing use patterns. Then, adjustments can be made to increase the capacity of recreation sites that are showing increased use (eg campgrounds).

TABLE 5 

Summary of climate change vulnerabilities and adaptation options for recreation in the Rocky Mountains. (Table continued on next page.)

Discussion

Communities in the rural American West rely on ecosystem services for necessities like water, recreation, and resource-based jobs. As climate change alters natural systems, more effort will be needed to protect the services provided by ecosystems. Adaptation will be critical in protecting ecosystem services and in meeting UN SDGs (UN 2015). The science–management partnership approach described here helped to facilitate the adaptation process in the Rocky Mountains. The process and outcomes will help to ensure that climate change is considered in future management of natural resources on federal lands in the Rocky Mountain region, thus helping to ensure sustainable development in the region (Table 6). Our approach can be applied in any location where there is sufficient engagement of scientists and local resource managers.

TABLE 6 

Contributions of the Northern Rockies and Intermountain Adaptation Partnerships to meeting the UN Sustainable Development Goals 6 and 15 in the Rocky Mountain region.

Our efforts are particularly relevant for water resources (SDGs 6.6, 15.1), which are expected to experience near-term changes in a warmer climate, but for which good options are available to reduce potentially negative outcomes (Table 2). Climate change will likely increase stress on limited water resources in the Rocky Mountains, which are already stressed by increasing populations. The headwaters, which are the primary source of water in the region, are mostly on public lands. Thus, watershed health and resilience in these headwaters is critical in protecting water quantity and quality for large populations, and federal agencies will play a key role in helping to protect water in a changing climate. Restoring and sustaining hydrological processes is a primary strategy for protecting water resources under a changing climate.

Although increased temperatures and atmospheric concentration of CO₂ have the potential to increase timber and forage production in the Rocky Mountains, those gains may be offset by wildfires, droughts, insect outbreaks, non-native species, and altered species composition (Littell et al 2013). Efforts to reduce negative outcomes of increased disturbance are relevant to SDG 15.4. Typical rates of return on livestock in the West are already as low as 2% (Holechek et al 1994), and private rangelands have become increasingly fragmented with land use change (Holechek 2001; Resnik et al 2006). Thus, climate change may render livestock operations unprofitable in the future. Rangeland managers often have limited financial resources and limited options to diversify livelihoods beyond livestock grazing, making the accelerated implementation of adaptation options critical (Briske et al 2015). Our assessment has identified ways in which federal land managers can help sustain forage productivity. For example, reducing introduction and spread of invasive species will be critical in sustaining productivity of rangelands in the future (relevant to SDG 15.8). Increasing communication between federal land managers and rangeland permittees will also help to ensure that sustainable grazing plans are developed.

Societal, economic, and policy changes have also affected timber on federal forests. Between 1998 and 2013, employment in the timber industry fell by a third in both the study area and throughout the United States (Warziniack et al 2017). These changes were driven by higher imports of wood products, declines in housing starts, changes in preferences for electronic media over paper, and growing emphasis on habitat preservation and amenity values of forests (Skog et al 2012; Weber and Chen 2012). Off-forest changes are likely to continue affecting on-forest harvest. However, to minimize negative effects of climate change, land managers can work to increase forest resilience in the near term, primarily by reducing dry forest density and increasing abundance of drought and disturbance resilient species (relevant to SDG 15.5). In the long term, species composition can be adjusted to promote diversity and sustain timber production.

While the “Old West” struggles, the “New West” is thriving in many Rocky Mountain communities, especially those with strong ties to recreation. Recreation spending in and near national forests and parks now exceeds revenue from timber in most parts of the western United States. This growth has led to a change in priorities for managers, from extractive commodities to leisure uses of the land. With changing climate, many of the demands for recreation may not match up with current management approaches for recreation in national forests and parks. Participants in the adaptation workshops repeatedly mentioned the need for recreation management systems that were more flexible, both for forest infrastructure like roads and trails and for concessionaire contracts that may not always align weather with peak demand from residents and tourists.

The effort described here highlighted the importance of federal lands in the Rocky Mountains in providing ecosystem services to society, and the ways in which federal land managers can adapt to the effects of changing climate. Federal agencies are now transitioning from the planning phase of climate change adaptation to implementation (Halofsky et al 2015), which will ensure that ecosystem services will continue to be provided from federal lands in a changing climate.