Threats posed by climate change are thrown into particularly sharp relief for high elevation alpine communities, which support flora and fauna often found nowhere else. Unlike lower elevation species that may adapt to a changing climate by migrating northward, alpine species will eventually have nowhere to go when climate conditions become inhospitable. However, scientists and managers are hopeful that certain topographical and ecological features of alpine ecosystems might promote persistence of valued alpine resources in the short-term. 

For example, the American pika, a rabbit-like mammal found only at high elevations, is sensitive to high temperatures and has disappeared from portions of its range. But evidence shows that pika are also sensitive to the vegetation, soil, hydrology, and rocky habitat features available to them (Beever et al. 2016, Smith et al. 2019), which presents the possibility that refugia for pika might be identified and then protected or promoted through management action. The same idea applies to other prioritized alpine fauna, like bighorn sheep and rosy-finches. 

High elevation flora, too, may benefit from a refugia approach. Whitebark pine is currently under threat from white pine blister rust and mountain pine beetle; appropriate management action for these pests may enable whitebark pine to make upslope shifts expected due to climate change. Additionally, the High Sierra Sky Islands, unglaciated plateaus found around 12,000-13,000 feet, contain a large diversity of plants found nowhere else, including the Sky Pilot (cherished by wildflower enthusiasts). Although these plant communities will eventually run out of vertical real estate in a warming climate, if mapping and modeling can be used to identify refugia, then management action -- like directing hikers away from sensitive areas, or assisted migration of plant species into refugia-- may enable short-term persistence of these valued resources.  

Focal Resources identified at November 8, 2019 workshop:

• American Pika (Ochotona princeps)

• Bighorn sheep (Ovis canadensis)

• Sierra Nevada Gray-crowned Rosy-Finch (Leucosticte tephrocotis dawsonii)

• Mountain yellow-legged frog (Rana muscosa)

• Whitebark Pine (Pinus albicaulis)

• Sky pilot (Polemonium eximium)

• High Sierra Sky Islands

  • High unglaciated plateaus containing diverse plant communities found nowhere else. Learn more: Yosemite Nature Notes: Sky Islands

Potential Management Actions:

Based on the focal resources, workshop participants identified potential management actions such as:

• Consider impact by climbers/hikers

• Monitor to learn about shifts in phenology and composition

• Translocation/assisted migration

  • Example: Reintroduction of Bighorn Sheep

Data on human recreation impacts could inform trail routing and signage that helps hikers and climbers avoid alpine refugia. Alpine plant phenology and community composition monitoring could be used in an adaptive management framework to inform assisted migration of prioritized plants.

Data Gaps/Future Work:

• Food web dynamics 

• Plant community

Current efforts, data, and partnerships that could support identification and mapping of alpine refugia: 

• Resurvey of Plant Communities (Dr. Dena Grossenbacher): currently underway, a multi-year study to re-sample ~650 alpine plots in Yosemite.

• Snow Surveys (to better model future persistence)

  • Yosemite Snow Surveys

  • California Cooperative Snow Surveys

• Hetch Hetchy Water and Power 2-week LiDAR data to find snowpack data for Sky Islands (5-7-year LiDAR record)

• Bighorn Sheep Occupancy/Habitat Use

  • Sierra Nevada Bighorn Sheep Recovery Program (including distribution and habitat suitability maps)

• Southern Sierra Leadership Forum: coalition to foster collaboration between agencies

  • Landscape-Scale Sierra Conservation

• Bighorn Sheep Biologists (NPS, CDFW)