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Places We Protect

San Andreas Corridor

California

A herd of pronghorn antelope cross a grassland with purple flowers.
Las Piletas TNC purchased Las Piletas Ranch in eastern San Luis Obispo County—13,528 acres of rolling foothills, grasslands and oak woodlands, along with 24 miles of streams. © Ethan Inlander/TNC

We’re working to create a wildlife linkage that spans nearly the entire Inner Coast Range, home of our state’s most connected—but least protected—wildlands.

Overview

Description

California’s Inner Coast Range contains what many consider to be the state’s most valuable unprotected wildlife linkage. The range runs along the San Andreas Fault, where tectonic activity created the conditions for amazing biodiversity, from plants found nowhere else on Earth to iconic species like pronghorn, tule elk, California tiger salamanders and the San Joaquin kit fox. The corridor is home to some of the largest swaths of intact and climate-resilient grasslands and blue oak woodlands in the state, vital but under-protected ecosystems.

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TNC’s vision for the San Andreas Corridor is to protect a wildlife linkage that spans the entire Inner Coast Range—a refuge on the scale required to support the full suite of the region’s native species in the face of climate change. Working closely with local land trusts, ranchers and more partners across the region, we hope to conserve 200,000 acres of the most ecologically important wild and working lands that enable wildlife movement, protect sensitive habitats and support communities by 2030.

The Power of a Connected California

To date, TNC has protected more than one million acres of land in California, and we partner with ranchers, farmers and families to protect and manage approximately 600,000 acres of working lands. The strategy that guides these efforts is driven by science that assesses the areas where our actions and resources can have the biggest impact. 

This thinking is laid out in TNC’s Resilient and Connected Network, which identifies and maps lands that are the most biodiverse, resilient to climate change and well connected to other natural lands—the three ingredients needed to sustain nature. The Resilient and Connected Network highlights the San Andreas Corridor as one of the most important landscapes to support wildlife habitat and movement in California, even as our climate changes.

Who Calls the Corridor Home? 

From far-ranging mammals like pronghorn and tule elk to desert dwellers like the San Joaquin kit fox, the San Andreas Corridor provides important habitat for many of California’s most iconic species. Click on the photos to expand.

Pronghorn antelope graze at Carrizo Plain in San Luis Obispo County, California.
Close up a Camatta Canyon amole with a measuring stick next to it.
San Joaquin kit fox looking away.
Closeup of a California tiger salamander on green moss.
Close up of a Foothill yellow-legged frog.
Pronghorn antelope graze at Carrizo Plain in San Luis Obispo County, California.

Pronghorn antelope: Pronghorn antelope graze at Carrizo Plain in San Luis Obispo County, California. © Larry Lamsa/Creative Commons

Close up a Camatta Canyon amole with a measuring stick next to it.

Camatta Canyon Amole: TNC is working to connect and create a stronghold for sensitive species, including the endangered Camatta Canyon amole. © USFWS

San Joaquin kit fox looking away.

San Joaquin kit fox: San Joaquin kit fox, whose habitat occupies much of the San Joaquin Valley. © DFW

Closeup of a California tiger salamander on green moss.

California tiger salamander : The California tiger salamander (Ambystoma californiense) is an endangered and endemic species that reproduces annually in vernal pools. © Natalie McNear

Close up of a Foothill yellow-legged frog.

Foothill yellow-legged frog: The foothill yellow-legged frog lives in foothill and mountain streams from the Pacific Coast to the western slopes of the Sierra Nevada and Cascades mountains. © Jonathan Hakim

View looking across a hilly landscape at sunset.
Mt. Hamilton landscape San Felipe Ranch, located within Mount Hamilton, is the missing link in a corridor of protected lands that stretches 70 miles from Pacheco Pass to Livermore Valley. © Ian Shive

Building on Success

When wild landscapes are connected, wildlife can move to track changing conditions, populations remain genetically healthy, ecosystems can recover from fire and floods more quickly and entire regions remain more resilient for both people and nature. In short, connectivity is one of the best tools we have to help nature thrive, especially as species adapt in the face of climate change.

The San Andreas Corridor already includes some remarkable protected areas—including the Carrizo Plain National Monument, Los Padres National Forest, Pinnacles National Park and Henry Coe State Park—as well as ecologically significant wild and working lands. Now, we need to connect these places. This means both protecting new areas that link together current natural strongholds and addressing barriers to connectivity such as highways and fencing. The corridor will not only preserve habitat connectivity for resident animals but also for those traveling to other important habitat strongholds like the Santa Cruz Mountains and the Sierra Nevada. 

Future Forests for the Mighty Oak

California’s oak trees are essential to the state, creating some of our most biodiverse ecosystems—and one of our least protected. Oaks provide critically important habitat for thousands of plant and animal species, support local economies and play a vital role in pulling carbon out of the atmosphere. But climate change, habitat conversion and incompatible land management threaten the continued survival of oaks, and efforts to save them have little room for error. Most oak woodlands support only a single tree species, which means that the loss of just one species from any area likely means loss of the entire oak ecosystem.

Our science has identified the blue oak woodlands in the San Andreas Corridor as some of the most climate-resilient in the state. We’ve been working in close partnership with researchers at UCLA to pioneer a new conservation approach that uses cutting-edge gene sequencing to inform management and protection of oaks. These findings allow us to better understand which oaks are most likely to produce new climate-resilient acorns and which may need a boost through restoration. With this knowledge in hand, we can identify, grow and protect California’s oak woodlands and all the life that they support.

Blue oaks on a grassy hill.
BLUE OAKS GET THE JOB DONE Blue oaks play a key role in Central California ecosystems. © Rachel Mason

Genomics Point to a Path Forward

In four new papers, researchers from UCLA and TNC constructed and analyzed the entire genetic code of hundreds of oak trees—including blue oak, coast live oak, island oaks and island oak hybrids—to more accurately determine which are best (and least) adapted to survive in a rapidly changing climate. They looked across California and TNC’s conservation estate to identify both the areas that are most resilient to future climate change and those under the most threat that might be in need of a restoration boost. This type of conservation science directly guides on-the-ground action by shaping both which areas TNC prioritizes for protection and how we manage our landscapes to increase the odds of successful restoration and sustainable oak growth into the future.

“We’re now putting this science into practice across California,” said Scott Butterfield, Land Program lead scientist for TNC. “By using genomic data to guide restoration and management at our TNC and partner preserves, we can test whether trees predicted to be more climate-resilient actually perform better on the ground. That kind of real-world validation is essential to scaling solutions that will sustain oak woodlands and the biodiversity they support into the future.”

These studies represent an important bridge between academic research and applied conservation that promises to supercharge efforts to conserve hundreds of thousands of acres of important habitat, and which could become a template for conservation efforts for other vital species in California and around the world.

A History of Protection

Collaboration Is Key

Building a network of conserved lands in an area that spans 5.1 million acres and 14 counties requires a collaborative approach. That’s why we’ve teamed up with local and regional conservation organizations, government agencies and landowners to pursue the conservation of 200,000 acres of ecologically important wild and working lands in the region by 2030. While our partners leverage their local knowledge and relationships to identify important conservation opportunities, TNC uses our resources and expertise to help reduce critical roadblocks to protection.

The San Andreas Corridor is mostly comprised of large, working cattle ranches, and the support and partnership of these ranchers is crucial to achieving our goals. A key part of our protection strategy involves conservation easements, which protect nature while also helping ranching families to maintain their way of life.

This easement means being able to continue working the ranch, cultivating it, being here, living on it and then passing it on to future generations. This was a make-or-break opportunity for the ranch.
Haustin Morrison, Camatta Ranch
Closeup of poppies and other native plants.
California poppies Parker Ranch © Ian Shive

Ensuring a Family Legacy

In 2019, the Morrison family approached The Land Conservancy of San Luis Obispo (LCSLO), hoping to find an alternative to partitioning off or selling their ranch. Instead, they wanted to preserve both their family’s multi-generational legacy at Camatta Ranch and the vast, connected wildlands (an area roughly the size of San Francisco). With the help of LCSLO and partners including TNC, LegacyWorks Group and multiple state agencies, that dream became a reality.

This coalition helped to secure a historic conservation easement at Camatta Ranch, protecting more than 27,000 acres of blue oak woodlands, grasslands and chaparral while leaving ownership in the Morrisons’ hands. A conservation easement is a voluntary agreement between landowners and a land trust to maintain the unique ecological values and open space character of the property, which remains in effect even if the land is sold or passed on within the family.

“This easement means being able to continue working the ranch, cultivating it, being here, living on it and then passing it on to future generations. This was a make-or-break opportunity for the ranch,” said Haustin Morrison. “This property is [going to] be here way past me and my family. Our time here is short, but this property is protected forever.”

With the easement in place, TNC is proud to entrust the management and monitoring of the property in the able hands of the Morrison family and The Land Conservancy of San Luis Obispo and turn our focus toward the next high-impact opportunity to make sure nature has a place in California’s future.

A Living Laboratory for Wild and Working Lands

Our work in the San Andreas Corridor isn’t just about protecting the land. We are also developing innovative science and conservation solutions to improve the ability for wildlife to move through this important linkage and enhance habitat while also supporting the working lands legacy of the region. An active cattle ranch, Las Piletas Ranch Preserve acts as a living laboratory where our science and stewardship teams collaborate with grazing partners to test and refine land management practices. These practices and lessons learned are then shared with landowners and the broader land conservation community to expand the influence and impact of the lands we manage.

At Las Piletas Ranch Preserve, TNC is testing and refining different actions that land managers can take to benefit, sustain and ultimately recover declining pronghorn populations. Our science team and partners identified the key problems for pronghorn: fences as an impediment to finding refuge and food and a lack of availability of food and water in a relatively dry landscape. In collaboration with researchers at Cal Poly San Luis Obispo and neighbors including the California Department of Fish and Wildlife and the Bureau of Land Management, our teams are now working to re-establish year-round water sources for pronghorn and using wildlife cameras and AI to track their effects on birth rates, survival and population growth. We’re also testing new approaches to restoration and management to grow more sustainable forage resources, especially late in the season when grasses are brown and fawns are most sensitive. And we’re modifying and removing fences (enabled by virtual fencing technology) to allow pronghorn to move across the San Andreas Corridor—increasing access to suitable habitat now and in the future.

What Goes on at Las Piletas Ranch Preserve?  

This living laboratory gives us the opportunity to incorporate innovative technologies like virtual fencing and remote sensing into rangeland planning. Click on the photos to learn more about our work on the ground.   

A group of pronghorn gather at a watering station.
A still from a wildlife camera showing a young pronghorn encountering a coyote.
Still from a wildlife camera showing two pronghorn running in grass alongside a wire fence.
Cows with virtual fencing collars.
A group of pronghorn gather at a watering station.

Water for Wildlife: Pronghorn enjoy year-round water sources provided by TNC. © TNC

A still from a wildlife camera showing a young pronghorn encountering a coyote.

AI Monitoring: Machine learning helps identify what’s being captured on TNC’s wildlife cameras, such as this young pronghorn encountering a coyote. © TNC

Still from a wildlife camera showing two pronghorn running in grass alongside a wire fence.

Removing fencing: Pronghorn take advantage of new spaces to roam as TNC and partners remove barbed wire as we transition to virtual fencing. © TNC

Cows with virtual fencing collars.

Virtual fencing: New collars can manage where cows graze using virtual fencing technology, creating more open spaces for wildlife on the ranch. © TNC

Funding the Future

Historically, the largely wild landscapes of the San Andreas Corridor were under great threat and therefore lacked both public and private funding for conservation. Today, with the expansion of vineyards, residential subdivisions and energy development, that threat is becoming more evident, and the need to protect the corridor is becoming more urgent.

One major funding success story is the passage of Proposition 4, a bond measure that TNC helped to pass in 2024. TNC and our partners worked to highlight the statewide importance of this landscape and secured the allocation of $80 million of state funding for the protection and restoration of the San Andreas Corridor. But TNC’s success in the corridor also depends on private funding, which allows us to move quickly in a fast-paced real estate market, as well as fund the essential science needed to guide protection and restoration.  

Luckily, compared to much of California, where land prices exceed $10,000 per acre, much of the San Andreas Corridor averages $1,500 per acre or less, making it one of the most cost-effective conservation opportunities in the state. This—along with the incredible biodiversity and climate resilience of this landscape—yields an incredible return on investment for conservation.

WHERE WILDLANDS MEET WORKING LANDS (57:25) Life doesn’t stay still: it moves, migrates and adapts to survive. The future of countless California species depends on a large, connected network of wildlands—and TNC and partners are thinking big to make it happen. Watch the webinar!