San Diego County Ecosystems: 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. This assessment will be a part of California’s Fourth Climate Change Assessment.


The Mediterranean ecosystems of southern California are some of the most ecologically diverse systems outside of the tropics. The richness and diversity of plants and animals, as well as high rates of endemism, make the area a biodiversity hotspot. San Diego County is a particularly unique part of southern California, considering the region’s complex topography and highly variable precipitation and other climatic factors, which play an important role in determining the resident biological palette. Climate change would very likely aggravate parts of the already challenging climate of the region and add to other stressors. San Diego is home to a major metropolitan area, and is burdened by extensive fragmentation in the form of roadways and suburban-rural development. Within this complex, 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.

In partnership with the Climate Science Alliance – South Coast, a unique collaboration of local ecologists and climatologists conducted a review of the impacts of climate change on San Diego County’s terrestrial ecosystems. In this assessment, we review the state of the science on the natural climate variability and projected climatic changes, and describe the region’s unique diversity of ecosystems, habitats, plants, and animals. The assessment includes a review of the susceptibility of the region’s ecosystems to impacts from climate variability and relevant synergistic impacts of anthropogenic factors that may be exacerbated by a changing climate (e.g., urban growth, land use shifts, and fire regimes). We explore the most regionally-relevant climate adaptation strategies that can be applied to buffer the effects of climate variability and provide several case-study examples of adaptation projects that have been successfully implemented in San Diego’s terrestrial ecosystems. We also conducted a needs assessment to identify needed science efforts such as long-term monitoring, climate modeling and projections, and ecosystem modeling that may facilitate change detection, adaptive management, and risk planning for the region.

Abstract Authors
  • Megan K. Jennings, San Diego State University
  • Dan Cayan, Scripps Institution of Oceanography
  • Julie Kalansky, Scripps Institution of Oceanography
  • Amber D. Pairis, Climate Science Alliance
  • Dawn Lawson, Space and Naval Warfare Systems Center Pacific (SSCPAC)
  • Alexandra D. Syphard, Conservation Biology Institute
  • Udara Abeysekera, Climate Science Alliance
  • Rachel E.S. Clemesha, Scripps Institution of Oceanography
  • Alexander Gershunov, Scripps Institution of Oceanography
  • Kristen Guirguis, Scripps Institution of Oceanography
  • John M.Randall, The Nature Conservancy, California Chapter
  • Eric D. Stein, Southern California Coastal Water Research Project
  • Sula E. Vanderplank, San Diego State University
Additional Contributors
  • Horacio de la Cueva, Centro de Investigación Científica y de Educación Superior de Ensenada, Baja California
  • Shasta Gaughen, Pala Band of Mission Indians
  • Janin Guzman-Morales, Scripps Institution of Oceanography
  • Laura Hampton, Climate Science Alliance-South Coast
  • David W. Pierce, Scripps Institution of Oceanography
  • Hiram Rivera Huerta, Universidad Autónoma de Baja California
  • Rob Roy, La Jolla Band of Luiseno Indians