Southern California Coastal Sage Scrub: A Vanishing Ecosystem

September 2025

The Southern California Coastal Sage Scrub (CSS) is a unique and biologically rich ecosystem found primarily along the lower elevations of Southern California’s coast and inland valleys. Often overlooked in favor of lush forests or dramatic desert landscapes, coastal sage scrub is subtle but vital — home to an array of endemic species, complex plant communities, and important ecological processes. Unfortunately, it’s also one of the most threatened habitats in California.

What Is Coastal Sage Scrub?

Coastal sage scrub is a plant community dominated by aromatic, drought-deciduous shrubs such as California sagebrush, black sage, white sage, and buckwheat. These plants are well-adapted to the Mediterranean climate of Southern California, which features cool, wet winters and long, hot, dry summers.

A Biodiversity Hotspot

Despite its unassuming appearance, coastal sage scrub supports a remarkable range of wildlife, including many species found nowhere else in the world. One of the most iconic is the California gnatcatcher, a small gray bird that relies almost exclusively on coastal sage scrub habitat and has become a symbol of conservation efforts in the region.

CA Gnatcatcher

Ecological Importance

Coastal sage scrub plays a vital ecological role in:

  • Preventing erosion on dry slopes and hillsides

  • Providing corridors for wildlife movement between fragmented open spaces

  • Serving as carbon sinks and regulating local microclimates

  • Hosting pollinators critical to both wild and agricultural ecosystems

Threats to Coastal Sage Scrub

Once covering over two million acres in Southern California, coastal sage scrub has been reduced by more than 90% due to:

  • Urban sprawl and development

  • Agricultural conversion

  • Invasive species (e.g., mustard and grasses that outcompete natives)

  • Frequent wildfires fueled by non-native plants

This rapid loss has led to CSS being designated a threatened ecosystem under both state and federal conservation frameworks.

What You Can Do

You don’t need to be a land manager to help coastal sage scrub thrive. Here are a few ways individuals can contribute:

  • Plant native drought-tolerant species in your yard or garden

  • Volunteer with local restoration projects, such as; PWP’s Land Steward Program

  • Stay on designated trails when hiking to avoid trampling sensitive habitats

  • Donate to conservation organizations working in Southern California, such as; PWP.

Southern California’s coastal sage scrub is more than just a backdrop to coastal cities — it is a living, breathing, fragile ecosystem that tells the story of this region’s natural heritage. As pressures from human development rise, preserving this irreplaceable biome becomes not just an environmental imperative, but a moral one. By recognizing the value of coastal sage scrub and actively participating in its protection, we can help ensure that future generations experience its subtle beauty and rich biodiversity.

Preserve Wild Poway (PWP) is a dedicated, volunteer, 501 c 3 nonprofit, whose goal is to actively protect, maintain, and preserve local habitat. If you are worried about the loss of endangered habitat and wildlife, we welcome you to join us.

Please sign up online to volunteer or donate at www.preservewildpoway.org

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