Approach
EASTERN: Some sites host a higher diversity of species than adjacent sites, have many endemic species, have a sheltered topographic position, or have retained species through past periods of climate change. These potential refugia are formed through spatial, geophysical, and biological variation on the landscape and may be identified as unique sites that are expected to be more resistant to change. These sites may provide the best chance to retain habitat for native species under future climate change. Species at these sites are not necessarily sensitive or at-risk, although they may face increased stress under future climate on some landscape positions. Committing additional resources may be necessary to ensure that the characteristic site conditions are not degraded by invasive species, herbivory, fire, or other disturbances.
WESTERN: Some sites host a higher diversity of species than adjacent sites, have many endemic species, or have retained species through past periods of climate change. These locations of high ecological value can be identified at multiple scales and may occur as a result of many factors, including geophysical factors such as complex topography, variation in geology and soils, variation in microclimates due to vegetation differences, or variation in hydrology, including access to cold groundwater or climatic buffering from large surface waters. When these factors moderate exposure to climate change, they are often referred to as climate refugia. Species at these sites are not necessarily sensitive or at-risk, although they may face increased stress under future climate on some landscape positions. Committing additional resources may be necessary to ensure that the characteristic site conditions are not degraded by invasive species, herbivory, altered fire regimes, or other disturbances.
Tactics
- Identifying and managing cooler and wetter locations (i.e., locations with a relatively lower future climate exposure) that are expected to be more resistant to changes in climate as refugia for maintaining native plant communities into the future.
- Limiting harvest or management-related disturbance in areas that may be buffered from climate change (e.g., spring-fed stands sheltered in swales or valleys).
- Identifying and protecting a network of sheltered mountain slopes, valleys, or forests with continuous shading canopy (such as along canyon bottoms or riparian corridors).
- Identifying areas with unique geology, landform, soils (e.g., serpentine parent material soils) or vegetation (e.g., endemic species) for increased protection or conservation.
- Protecting areas that have been generally undisturbed by humans, such as those within old-growth forest, peatlands, barrens, or prairie, in order to preserve a reference condition or legacy.
- Identifying forested slopes (i.e., north facing) that retain snowpack later into the spring/summer than other sites, and manage actions on these sites with the goal of retaining the benefits they provide to freshwater habitats and flows.
- Protecting areas that have been generally undisturbed by humans, such as those within old forests, old-growth chaparral, subalpine stands, or prairie, in order to preserve a reference condition or legacy while allowing for natural processes...
Strategy
Strategy Text
Refugia are areas that have resisted ecological changes occurring elsewhere, often providing suitable habitat for relict populations of species that were previously more widespread. Climate refugia are often formed by topography (e.g., north sides of slopes, or sheltered ravines), proximity to large water bodies, or connection to groundwater. An excellent example of this are the 75 or so giant sequoia (Sequoiadendron giganteum) groves scattered across the Sierra Nevada mountain range that have persisted in sites that are relatively more mesic and have reliable summer moisture. Springs and other sites with strong connections to groundwater can provide cool water refugia (Cartwright et al. 2020), and are critical habitat for a variety of California’s threatened and endangered species. During previous periods of rapid climate change, at-risk populations persisted in refugia that avoided extreme impacts. These populations allowed species to persist until more favorable climatic conditions returned and species were able to expand into newly available habitats. This strategy seeks to identify and maintain habitats that: (1) are on sites that may be better buffered against climate change and short-term disturbances, and or (2) contain communities and species that are at risk across the greater landscape.
1. Swanston, C.W.; Janowiak, M.K.; Brandt, L.A.; Butler, P.R.; Handler, S.D.; Shannon, P.D.; Derby Lewis, A.; Hall, K.; Fahey, R.T.; Scott, L.; Kerber, A.; Miesbauer, J.W.; Darling, L.; 2016. Forest Adaptation Resources: climate change tools and approaches for land managers, 2nd ed. US Department of Agriculture, Forest Service, Northern Research Station. 161 p. http://dx.doi.org/10.2737/NRS-GTR-87-2