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Abstract

Climate change vulnerability and adaptation in South-Central Oregon.

Abstract

The South-Central Oregon Adaptation Partnership (SCOAP) was developed to identify climate change issues relevant for resource management on federal lands in south-central Oregon (Deschutes National Forest, Fremont-Winema National Forest, Ochoco National Forest, Crooked River National Grassland, Crater Lake National Park). This science-management partnership assessed the vulnerability of natural resources to climate change and developed adaptation options that minimize negative impacts of climate change and facilitate transition of diverse ecosystems to a warmer climate. The vulnerability assessment focused on water resources and infrastructure, fisheries and aquatic organisms, vegetation, wildlife, recreation, and ecosystem services. The vulnerability assessment shows that the effects of climate change on hydrology in south-central Oregon will be highly significant. Decreased snowpack and earlier snowmelt will shift the timing and magnitude of streamflow; peak flows will be higher, and summer low flows will be lower. Projected changes in climate and hydrology will have far-reaching effects on aquatic and terrestrial ecosystems, especially as frequency of extreme climate events (drought, low snowpack) and ecological disturbances (flooding, wildfire, insect outbreaks) increase. Distribution and abundance of cold-water fish species are expected to decrease in response to higher water temperature, although effects will vary as a function of local habitat and competition with nonnative fish. Higher air temperature, through its influence on soil moisture, is expected to cause gradual changes in the distribution and abundance of plant species, with drought-tolerant species becoming more dominant. Increased frequency and extent of wildfire and insect outbreaks will be the primary facilitator of vegetation change, in some cases leading to altered structure and function of ecosystems (e.g., more forest area in younger age classes). Vegetation change will alter wildlife habitat, with both positive and negative effects depending on animal species and ecosystem. Animal species with a narrow range of preferred habitats (e.g., sagebrush, riparian, old forest) will be the most vulnerable to large-scale species shifts and more disturbance. The effects of climate change on recreation activities are more difficult to project, although warmer temperatures are expected to create more opportunities for warm-weather activities (e.g., hiking, camping) and fewer opportunities for snow-based activities (e.g., skiing, snowmobiling). Recreationists modify their activities according to current conditions, but recreation management by federal agencies has generally not been so flexible. Of the ecosystem services considered in the assessment, timber supply and carbon sequestration may be affected by increasing frequency and extent of disturbances, and native pollinators may be affected by altered vegetation distribution and phenological mismatches between insects and plants. Resource managers in the SCOAP developed adaptation options in response to the vulnerabilities of each resource, including high-level strategies and on-the-ground tactics. Many adaptation options are intended to increase the resilience of aquatic and terrestrial ecosystems, or to reduce the effects of existing stressors (e.g., removal of nonnative species). In terrestrial systems, a dominant theme of adaptation in south-central Oregon is to accelerate restoration and fuel treatments in dry forests to reduce the undesirable effects of extreme events and high-severity disturbances (wildfire, insects). In aquatic systems, a dominant theme is to restore the structure and function of streams to retain cold water for fish and other aquatic organisms. Many adaptation options can accomplish multiple outcomes; for example, fuel treatments in dry forests reduce fire intensity, which in turn reduces erosion that would degrade water quality and fish habitat. Many existing management practices are already "climate smart" or require minor adjustment to make them so. Long-term monitoring is needed to detect climate change effects on natural resources, and evaluate the effectiveness of adaptation options.