Walnut Creek-based Save Mount Diablo has signed a deal to protect 55 acres at Pacheco Pass in Santa Clara County. The conservation easement would be the nonprofit land trust's first acquisition in Santa Clara County and its farthest south ever, according to the organization.
The organization announced Monday, Oct. 12, that it signed a purchase-and-sale agreement with conservation biologist Joseph Belli to acquire the easement for under $250,000. Belli agreed to sell the easement below fair market value. Save Mount Diablo expects to close the deal by the end of December.
"We are grateful and honored that Joseph Belli, a renowned Diablo Range expert, has entrusted Save Mount Diablo to permanently protect his beloved Pacheco Pass property," executive director Ted Clement said in a statement.
Founded in 1971, Save Mount Diablo has historically focused its land acquisitions on and around Mount Diablo in Contra Costa County. During its 2025–2026 fiscal year, it expanded its scope to consider acquisitions across all 12 counties of the Diablo Range, according to its annual impact report.
Why the corridor matters
The Pacheco Pass property sits in a wildlife corridor where State Route 152 impedes animal movement. Save Mount Diablo said the California Department of Fish and Wildlife identified the highway in Pacheco Pass as a top-priority barrier to address.
Belli purchased the land in 1992 and named it the Pacheco Pass Wildlife Research Station. He envisioned it as a hub for ecologists and wildlife biologists studying the Diablo Range.
More than 100 bird species have been recorded on the property, including California condor. Bobcat, tule elk, mountain lion, golden eagle and bald eagle have also been observed there, according to Save Mount Diablo.
The property is part of a wildlife corridor connecting three Diablo Range counties: Santa Clara, San Benito and Merced. It links habitat between Quien Sabe, Pacheco State Park and Henry W. Coe State Park, according to the nonprofit. The Santa Clara Valley Habitat Agency is separately working on plans for a wildlife overcrossing in the Pacheco Pass area to reduce roadkill and improve animal movement across the highway, as described in its project planning document.
State conservation push
The California Senate unanimously approved Assembly Concurrent Resolution 107 (ACR 107) on Aug. 13, recognizing the Diablo Range as a state conservation priority, according to the official legislative record. Assemblymember Rebecca Bauer-Kahan authored the resolution, which Save Mount Diablo sponsored. The designation supports California's 30x30 initiative, which aims to conserve 30% of the state's land and coastal waters by 2030.
Save Mount Diablo describes the Diablo Range as stretching more than 200 miles, spanning 12 counties and covering more than 4 million acres. Less than 30% of the range is conserved, according to the organization.
Belli wrote The Diablo Diary and Beneath a Black and White Sky: A Year Among Condors at Pinnacles National Park. He has worked to support endangered species in the range, including California condors, blunt-nosed leopard lizards and foothill yellow-legged frogs, according to Save Mount Diablo.
Save Mount Diablo's closing target is the end of December 2026, pending completion of due diligence.
