Biodiversity in California

 Biodiversity refers to the variety of life, from genes to species to ecosystems. 1 California is considered a global “biodiversity hotspot,” home to an exceptional variety of species and ecosystems.2 Thousands of plants and animals found nowhere else on Earth rely on the habitat created by California’s diverse landscapes, seascapes, and the freshwater systems that connect them.3 

Why do biodiversity hotspots matter? Despite accounting for only 2.5% of global land<br>area, biodiversity hotspots support more than half of the world’s endemic plant species and over 40% of endemic bird, mammal, reptile, and amphibian species.

Our state’s unique biodiversity is under threat. California has the most imperiled biodiversity of any state in the contiguous United States.4 Over the last two centuries 75% of the state’s native vegetation, including over 90% of California’s wetlands, has been altered, impacting ecosystems across California.5,6 Blue oak woodlands, riparian zones, and grasslands now occupy a small fraction of their historic range. Meanwhile, climate change has shifted species ranges both on land and in coastal waters. Additionally, pollution, water diversion, and invasive species have severely altered ecosystem dynamics. 

Protecting our state’s extraordinary biodiversity requires adaptive management in key areas across the state, including within our working landscapes, inland waters, and seascapes. It will also require conserving and actively managing areas that will safeguard biodiversity as the climate changes. 

– Excerpt from Pathways to 30×30, Administration of Governor Gavin Newsom, April 22nd 2022

https://www.californianature.ca.gov.

BIODIVERSITY DAY CELEBRATIONS
September 6-14, 2025

September 7th is California Biodiversity Day, a time to inspire discovery and connection to California’s amazing biodiversity, and to encourage actions to protect it! 

Check out the California Biodiversity Day website for events and how to participate! 

QUESTIONS? COMMENTS?

Please contact californiabiodiversityday@wildlife.ca.gov

The Biodiversity Day Planning Team includes representatives from the following organizations: CA Department of Fish and Wildlife, California State Parks, CA Natural Resources Agency, Ocean Protection Council, the California Academy of Sciences, the California Native Plant Society, Power in Nature, and UCANR’s Environmental Stewards Program.

  1. Gaston, Kevin J., and John I. Spicer. 2013. Biodiversity: an introduction. John Wiley & Sons. ↩︎
  2. Myers, N., Mittermeier, R., Mittermeier, C. et al. 2000. Biodiversity hotspots for conservation priorities. Nature 403: 853–858. https://doi. org/10.1038/35002501. ↩︎
  3. Tershy, B. et al. 2015. Ecosystems of California. https://ccal.ucsc.edu/wp-content/ uploads/2017/03/Tershy_2015b.pdf ↩︎
  4. Hamilton, Healy, Regan L. Smyth, Bruce E. Young, Timothy G. Howard, Christopher Tracey, Sean Breyer, D. Richard Cameron et al. 2022. Increasing taxonomic diversity and spatial resolution clarifies opportunities for protecting imperiled species in the US. Ecological Applications e2534.  ↩︎
  5. US Department of the Interior. 1994. The impact of federal programs on wetlands, vol. II, a report to Congress by the Secretary of the Interior, Washington DC, March 1994.  ↩︎
  6. Dahl, T. E. 1990. Wetland losses in the United States 1780’s to 1980’s. Washington, D.C.: U.S. Department of the Interior, Fish and Wildlife Service.  ↩︎