Wet Meadow Ecosystems Climate Change Vulnerability, Adapta on Strategies, and Management Implica ons General Informa on: Wet meadows are well distributed across the Sierra Nevada at different eleva ons, but account for only 1% of total area. The southern Sierra, with its steeper topography and drier climate, has less meadow area than the northern Sierra. Sierra Nevada wet meadows are largely defined by their hydrology; for example, meadows in mid- to high- eleva ons usually receive water supply from snowmelt. Other water sources for meadows include overland flow, surface flow and/or groundwater entering via stream and spring networks, and direct precipita on. Wet meadows are important ecosystems, providing key habitat for numerous species as well as a variety of ecosystem services including water filtra on, a enua ng floods, aesthe c value, and water © Wikimedia storage, among others. Component species include: sedge species (Carex spp.), rush species (Juncus spp.), and tu ed hairgrass (Deschampsia cespitosa).
Ecosystem Vulnerability: Moderate-High Very Low Very High Wet meadows are highly sensi ve to changes that impact hydrology, as meadow distribu on, type, and vegeta on are determined by local hydrological condi ons. Climate and climate-driven changes that may affect meadow hydrology include shi s from snow to rain, reduced snowpack, earlier snowmelt ming, and increased evapotranspira on. Non- climate stressors such as water diversions, grazing, recrea onal ac vi es, and fire suppression can further increase meadow vulnerability by degrading their current condi on and/or altering hydrology.
Projected Climate and Impacts on Regional Hydrology Impacts on Wet Meadows Climate-Driven Changes Decreased snowpack (-64% to • Reduced spring and summer soil moisture • Tree and shrub -87%) encroachment Earlier snowmelt and runoff • Advanced runoff center of mass (1-7 weeks • Erosion of topsoil and moist ming & shi s from snow to earlier) peat rain • Flashier runoff, higher flow magnitudes but • Channel incision and reduced mean annual flow erosion leading to meadow • Reduced groundwater recharge drying • Longer dry season • Less water stored for use Increased evapotranspira on • Increased clima c water deficit (i.e., reduced • Tree and shrub soil moisture) by up to 44% encroachment
Although wet meadows occur across a diverse eleva onal range, their vulnerability is increased by low connec vity and Wet meadows fed by northerly exposed non-uniform, fragmented distribu on. In addi on, wet watersheds, in cold sinks, or in watersheds meadows are one of the most altered and impacted systems with minimal hydrologic altera ons may be in the Sierra Nevada; a degraded state reduces their ability to more resilient to projected clima c condi ons adapt or be resilient to climate and climate-driven changes. Adapta on Strategies for Wet Meadow Ecosystems Adapta on Strategy Specific Management Ac ons Restore floodplain func on to enhance • Plug and pond (redirect flow from incised channels to stable channel ecosystem integrity and resilience under with broad floodplain) climate change • Establish setbacks • Stabilize banks and headcuts • Restore meanders, soils and structure • Promote beavers where appropriate to keep water in the system Reduce nega ve impacts of grazing, as • Increase monitoring to include biological diversity indices that these impacts have the poten al to evaluate climate and non-climate impacts and management ac on amplify climate change effects effec veness for key biological parameters • Re-examine livestock densi es and grazing intensity, ming, and season in light of climate change predic ons Increase role of fire to limit high severity • Restore natural fire regime (wildland fire, prescribed fire, fire fires, insect and disease outbreaks, and reintroduc on) to minimize fuel loading and reduce poten al for high moisture stress severity fires • Prac ce fuels reduc on Reduce nega ve impacts of recrea on, • Assess and consider removing roads (or altering ming of use) in roads, and trails to help wet meadows sensi ve meadows areas be er cope with climate change effects • Enhance route designa on plans in light of projected climate change impacts
Preven ng anthropogenic degrada on or hydrological altera on of wet meadows can enhance resilience to climate change ©Ma Lavin © Wikimedia
Management Implica ons This informa on can be used in a variety of ways: ✔ Forest Plan Revisions ✔ U.S. Forest Service Climate Change Performance Scorecard: Element 6 - “Assessing Vulnerability” and Element 7 - “Adapta on Ac ons” ✔ Na onal Park Service Resource Stewardship Strategies, Fire and Fuel Management Plans, General Management Plans, Strategic Plans, and Wilderness Stewardship Plans
Further informa on and cita ons can be found in source reports, A Climate Change Vulnerability Assessment for Focal Resources of the Sierra Nevada and Climate Change Adapta on Strategies for Focal Resources of the Sierra Nevada, available online at the EcoAdapt Library: h p://ecoadapt.org/library.