San Diego National Wildlife Refuge
Earth Discovery Institute is working in partnership with the U.S. Fish and Wildlife Service (USFWS) to restore cactus scrub habitat at the San Diego National Wildlife Refuge in southern San Diego County. This three-year project focuses on expanding and connecting habitat for the Coastal Cactus Wren, a California Species of Special Concern whose populations have declined due to habitat loss, fragmentation, invasive species, and wildfires.
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The project will establish 56 new cactus patches across 139 acres near Sweetwater Reservoir, creating additional nesting and foraging habitat and improving connectivity between existing wren populations.
Restoring Coastal Cactus Wren Habitat
The Coastal Cactus Wren (Campylorhynchus brunneicapillus sandiegensis) depends on mature stands of cholla and prickly pear cactus for nesting, shelter, and foraging. With limited dispersal abilities, these birds rely on connected patches of suitable habitat to maintain healthy populations and genetic diversity.
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In 2007, the Harris Fire destroyed nearly all cactus scrub habitat at the San Diego National Wildlife Refuge, eliminating the local Coastal Cactus Wren population. Since then, USFWS has restored 171 cactus patches, but habitat fragmentation and invasive grasses continue to limit the species' recovery.
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The refuge is identified as a high-priority conservation area because of its potential to support a larger, interconnected Coastal Cactus Wren population and strengthen connections between populations in southern San Diego County.
Our Restoration Work
Building on previous USFWS restoration efforts, EDI is working to improve habitat conditions through several activities:​
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Habitat restoration: Planting approximately 5,600 cholla and prickly pear cactus cuttings to establish new habitat patches and improve connectivity.
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Invasive species management: Removing non-native grasses that compete with native vegetation, reduce food availability, and increase wildfire risk.
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Ecological monitoring: Conducting annual Coastal Cactus Wren surveys, vegetation monitoring, and photo-point monitoring to track habitat recovery and restoration success.
Once established, the restored habitat is expected to support up to 10 additional Coastal Cactus Wren breeding territories, contributing to the long-term recovery of this declining species.
Community Involvement
Community participation is an important part of this project. EDI will host volunteer restoration events, providing opportunities for local residents to participate in hands-on conservation and learn about San Diego's native ecosystems.
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Volunteers will help plant native cactus, remove invasive vegetation, and support habitat maintenance, contributing directly to the recovery of this important habitat.
Project Partners & Funding
This project is funded by the State of California Wildlife Conservation Board and implemented by Earth Discovery Institute in partnership with the U.S. Fish and Wildlife Service, which manages the San Diego National Wildlife Refuge.
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Project period: 2026–2029
