Adapting to climatic variability and ecosystem responses in the US National Forest System
Recent research and species distribution modeling predict large changes in the distributions of species and vegetation types in the western interior of the United States in response to climate change. Climate change results in broad and often complex environmental effects that create new challenges for resource managers and decision-makers and that often leave them asking questions about how to plan and respond to changes, both existing and predicted for the future. These changes and the level of uncertainty in predictions and likely responses make it difficult to accurately predict, plan and design management actions to minimize undesirable climate change impacts or select targets to plan and act upon. Furthermore, resource managers such as those in the USDA Forest Service are increasingly tasked with meeting vulnerability assessment and adaptation goals, yet they lack a firm basis for choosing approaches for assessing vulnerability, selecting targets, and facilitating adaptation of species and ecosystems. New methods for assessing vulnerability of species and ecosystems need to be evaluated and compared to assist managers in determining which methods to use when. Such tools help decision-makers determine if active management to reduce impacts or facilitate adaptation is needed to meet conservation goals of an agency or organization.
This talk reviews existing climate models that predict species and vegetation changes in the western United States, and it synthesizes knowledge about climate change impacts on the native fauna and flora of selected ecosystems of the interior American West. Species' responses will depend not only on their physiological tolerances but also on their phenology, establishment properties, biotic interactions, and capacity to evolve and migrate. Current and predicted future responses of species and habitats to climate change are examined in relation to taxonomic group and ecoregion and with regard to other disturbances and management responses. Approaches designed by the Forest Service and others for evaluating vulnerability of species and ecosystems are compared, and case studies of vulnerability assessments and adaptive management are used to illustrate results. Assessment methods are available and can be selected based on availability of time and resources, and number and types of targets and objectives. The costs and benefits of assisted species migration as a tool in facilitating adaptation are evaluated in depth. The presentation ends with a summary of management decision support needs to consider when designing methods to evaluate, conserve, and restore ecosystems that are or may be impacted by climate change.