San Diego County Ecosystems:
The Ecological Impacts of Climate
Change on a Biodiversity Hotspot
Under the umbrella of the Climate Science Alliance, a team of ecologists and climatologists conducted a review of the most current, regionally specific climate information and paired that with current research on local species and habitats of the South Coast that are at risk due to climate variability and other stressors.
San Diego County Ecosystems: The Ecological Impacts of Climate Change on a Biodiversity Hotspot
This San Diego County Ecosystems assessment is included in California's Fourth Climate Change Assessment as a technical report.
The diverse ecosystems, habitats, plants, and animals in the San Diego County region will be impacted by climatic shifts in multifold ways due to current and future variability, along with other factors including habitat loss and fragmentation, land use shifts, and changing fire regimes. While home to a major metropolitan area, San Diego County still hosts expanses of native and preserved habitats where management and conservation action could be greatly enhanced through science-based assessments and planning for climate change and increased climate variability. Projections of climate change in the region include warming by 4-9˚ F on average, and a 15-25% decrease in fall and spring precipitation with an increase in variability resulting in more frequent and intense droughts punctuated by increasingly rare yet extreme precipitation and flooding events. In addition, an increase in fire events and potential lessening of coastal marine influence may also affect San Diego’s ecosystems. Climate warming superimposed upon the pronounced spatially-varying temperature in the San Diego region will likely be associated with range shifts for many species resulting in novel community assemblages and biotic interactions and could create phenological mismatches. More frequent and intense heat waves may disproportionately affect younger age classes and reduce reproductive and survival rates of species sensitive to temperature extremes. With increasingly variable precipitation, drought may occur more frequently due to increased occurrence of dry days and could intensify because of warmer temperatures. Since drought disproportionately affects some species, these projected changes may cause structural changes to ecosystems. Santa Ana winds, occurring during increasingly dry fall months, would create ideal fire conditions. Coastal low clouds and fog along San Diego’s coast buffer this zone from the effects of warming and drying through shading and cooling. Although these marine stratus clouds will remain a presence, future changes in this phenomenon are uncertain. The spatial and temporal scales at which climate variations and change operate must be considered to build resilience into natural systems. Effective conservation actions will need to build on ongoing efforts focused on landscape-scale planning rather than more traditional single-species approaches. To carry this out will require cross-jurisdictional, multidisciplinary collaboration by scientists, policy-makers, planners, land managers, and the broader conservation community, which has a decades-long history of accomplishment in San Diego County.
Megan K. Jennings, Ph.D, San Diego State University
Dan Cayan, Ph.D, Scripps Institution of Oceanography
Julie Kalansky, Ph.D, Scripps Institution of Oceanography
Amber D. Pairis, Ph.D, Climate Science Alliance South Coast
Dawn Lawson, Ph.D., Space and Naval Warfare Systems Center Pacific (SSCPAC)
Alexandra D. Syphard, Ph.D, Conservation Biology Institute
Udara Abeysekera, Climate Science Alliance South Coast
Rachel E.S. Clemesha, Ph.D, Scripps Institution of Oceanography
Alexander Gershunov, Ph.D, Scripps Institution of Oceanography
Kristen Guirguis, Ph.D, Scripps Institution of Oceanography
John M.Randall, Ph.D, The Nature Conservancy, California Chapter
Eric D. Stein, Ph.D, Southern California Coastal Water Research Project
Sula E. Vanderplank, Ph.D, Terra Peninsular A.C.
Horacio de la Cueva, Ph.D, Centro de Investigación Científica y de Educación Superior de Ensenada, Baja California
Shasta Gaughen, Ph.D, The Pala Band of Mission Indians
Janin Guzman-Morales, Ph.D, Scripps Institution of Oceanography
Laura Hampton, Climate Science Alliance South Coast
Hiram Rivera-Huerta, Ph.D, Universidad Autónoma de Baja California
David W. Pierce, Ph.D, Scripps Institution of Oceanography
Rob Roy, The La Jolla Band of Luiseño Indians
For the full report:
Jennings, Megan K., Dan Cayan, Julie Kalansky, Amber D. Pairis, Dawn M. Lawson, Alexandra D. Syphard, Udara Abeysekera, Rachel E.S. Clemesha, Alexander Gershunov, Kristen Guirguis, John M. Randall, Eric D. Stein, and Sula Vanderplank. (San Diego State University). 2018. San Diego County Ecosystems: Ecological Impacts Of Climate Change On A Biodiversity Hotspot. California’s Fourth Climate Change Assessment, California Energy Commission. Publication number: EXT-CCC4A-2018-010.
For the summary report:
Jennings, Megan K., Dan Cayan, Julie Kalansky, Amber D. Pairis, Dawn M. Lawson, Alexandra D. Syphard, Udara Abeysekera, Rachel E.S. Clemesha, Alexander Gershunov, Kristen Guirguis, John M. Randall, Eric D. Stein, and Sula Vanderplank. (San Diego State University). 2018. Summary Report, San Diego County ecosystems: ecological impacts of climate change on a biodiversity hotspot. Climate Science Alliance. San Diego, California.
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The California Wildlife Foundation, a recognized 501(c)3, serves as the fiscal sponsor for Climate Science Alliance and accepts donations on our behalf.
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We thank the institutions of each of the authors that provided in-kind support for our time to contribute to this unfunded collaboration:
San Diego State University, Scripps Institution of Oceanography, Climate Science Alliance - South Coast, CA Department of Fish and Wildlife, Space and Naval Warfare Systems Center Pacific, Conservation Biology Institute, the CA Chapter of the Nature Conservancy, and the Southern Coastal Water Research Project. Further, our additional contributors represented Centro de Investigación Científica y de Educación Superior de Ensenada, Universidad Autónoma de Baja California, the Pala Band of Mission Indians, and the La Jolla Band of Luiseño Indians.
The development of the summary report would not have been possible without the financial support of:
This material is based upon work supported by the U.S. Geological Survey under Grant/Cooperative Agreement No. G17AP00097 from the Southwest Climate Adaptation Science Center.