Download Oak Woodland Ecosystems

Oak Woodland Ecosystems Climate Change Vulnerability, Adapta5on Strategies, and Management Implica5ons © Yath General Informa5on: Oak woodlands exist largely (>80%) on private lands of the Sierra Nevada foothills. DistribuBon of remaining oak woodlands occurs on public lands at higher elevaBons (1219-­‐1828 m; 4000-­‐6000 L) with low fragmentaBon. Canopy species in oak woodlands include blue oak (Quercus douglasii), valley oak (Quercus lobata), canyon live oak (Quercus chrysolepis), and California black oak (Quercus kelloggii), as well as other species present in smaller amounts, such as Oregon white oak (Quercus garryana), incense cedar (Calocedrus decurrens), ponderosa pine (Pinus ponderosa), aspen (Populus tremuloides), willow (Salix spp.), and alder (Alnus spp.). Oak woodlands support over 330 species of birds, mammals, repBles, and amphibians – the highest animal biodiversity of all habitats in California. Ecosystem Vulnerability: Low-­‐Moderate Very Low Very High Although oak woodlands are sensiBve to climate and climate-­‐driven changes that can alter species composiBon or recruitment success -­‐ including reduced precipitaBon and soil moisture, and increased fire frequency and severity -­‐ oak woodlands are generally expected to expand in the future, as component species can tolerate warm condiBons, drought, and moderate fire condiBons. Oak woodlands are more sensiBve to non-­‐climate stressors, including herbivory, pathogens, insects, and habitat conversion for agriculture and urban/suburban development. For example, herbivory by caXle and wild animals in spring and summer can limit oak recruitment and seedling or sapling establishment, which may be naturally reduced by climaBc water deficits. Land use conversion has already significantly reduced oak woodland extent in California, and is likely to be a conBnued problem. Projected Climate and Climate-­‐Driven Changes Impacts on Oak Woodland Ecosystems Changes in precipitaBon and snowpack: -  Decreased summer and fall precipitaBon -  Decreased snowpack (-­‐64% to -­‐87%), especially in northern range -  Earlier snowmelt •  Changes in species composiBon •  Reduced soil moisture, which can affect recruitment and establishment •  Altered pathogen exposure Increased climaBc water deficit by up to 44%, especially in the northern range •  Reduced soil moisture, which can affect recruitment and establishment Increased fire frequency and intensity, with a 65% increase in area of oak woodlands burned •  Long term effects are unknown: -  Low intensity fire may prevent conifer encroachment and prepare adequate seedbed condiBons -  Moderate intensity fire resulBng in oak topkill may impair and/or prolong regeneraBon Bme Oak woodland resilience is generally enhanced by broad ecosystem distribuBon, high diversity, and drought-­‐ and wildfire-­‐tolerant adult trees. Once disturbed, however, this system has slow regrowth and regeneraBon rates, as seedlings are sensiBve to soil moisture deficits and wildfire. Low elevaBon oak woodlands occurring on private lands may be more vulnerable due to reduced management potenBal. Oak species that can tolerate warm and dry condi5ons (e.g., valley oak) may be more resilient to climate and climate-­‐driven changes than species that require cool, mesic condi5ons (e.g., canyon live oak) Adapta5on Strategies for Oak Woodland Ecosystems Adapta5on Strategy Specific Management Ac5ons Restore structure, funcBon, and composiBon of oak woodlands to limit high severity fires and moisture stress •  Plant naBve bunch grasses within oak woodlands to reduce spread of invasive species •  Use prescribed burning at small-­‐scales to remove non-­‐naBve grasses •  Plant and protect acorns and seedlings from browsing •  Fence priority oak areas or individual plants to exclude browsers IdenBfy and protect oak climate refugia to use as priority areas for conservaBon and restoraBon •  IdenBfy and prioriBze areas where water deficit is expected to be minimal •  Establish extra protecBon for priority refugia areas using management designaBons, management acBon plans, and by excluding humans and browsers Facilitate oak translocaBon by planBng “climate-­‐smart” seedlings in areas that will be climaBcally suitable in the future •  Plant exisBng genotypes that are beXer adapted to future condiBons (dry and warm) •  Plant seeds from a greater geographic range or from drier, warmer climates •  Maintain geneBc diversity Engage the public in oak woodland stewardship • 
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Maintain and enhance landscape habitat connecBvity and funcBon to support top predators, which will reduce herbivory thus limiBng synergisBc impacts on oak woodlands •  IdenBfy and prioriBze top predators for re-­‐introducBon/re-­‐establishment and evaluate habitat needs •  Implement habitat mapping to locate priority areas now and in the future •  Use connecBvity modeling (e.g., Circuitscape, www.circuitscape.org/) to idenBfy important pinch points for protecBon, and prioriBze climate-­‐
informed protecBon or restoraBon of these important areas Increase educaBon on intrinsic value and ecosystem services of oaks Encourage climate-­‐smart restoraBon acBviBes and volunteer work days Engage community service organizaBons Enhance stewardship on private lands Minimizing non-­‐climate stressors that compound climate-­‐
driven impacts on oak recruitment and fitness can help make this system more resilient to climate change Management Implica5ons This informaBon can be used in a variety of ways: ✔ Forest Plan Revisions ✔  U.S. Forest Service Climate Change Performance Scorecard: Element © EPA 6 -­‐ “Assessing Vulnerability” and Element 7 -­‐ “AdaptaBon AcBons” ✔  NaBonal Park Service Resource Stewardship Strategies, Fire and Fuel Management Plans, General Management Plans, Strategic Plans, and Wilderness Stewardship Plans ✔  May help facilitate public and private partnerships Further informaBon and citaBons can be found in source reports, A Climate Change Vulnerability Assessment for Focal Resources of the Sierra Nevada and Climate Change AdaptaBon Strategies for Focal Resources of the Sierra Nevada, available online at the EcoAdapt Library: hXp://ecoadapt.org/library.