• Diablo Rideglands Working Group - Conservation Report: July 2002

The Purpose

The Diablo Ridgelands Working Group is intended to establish and maintain a voluntary partnership of non-profit land management organizations and public agencies dedicated to the conservation, preservation, and management of natural, wild, agricultural, and recreational lands in the million-acre area known as the Diablo Ridgelands, for the purpose of enhancing the individual and collective effectiveness of the partners. Each member of the partnership has individual goals and priorities; all share a common desire to preserve the lands and habitats of the Diablo Ridgelands.

The Working Group is guided by the belief that the protection of the Diablo Ridgelands can be achieved utilizing a mosaic of public, non-profit and private land ownerships and conservation easements.

The Ridgelands

The Ridgelands consist of a series of parallel ridges and canyons trending in a northwest-southeast direction, defined by Mount Diablo in the north and Mount Hamilton in the south, and including associated uplands between the Carquinez Straits and Pacheco Pass.

In the south these ridges run together and form a massive uplift where Mount Hamilton is merely one peak among many, distinguishable primarily through the Observatory perched on its knife-edge ridge.

In the north this uplift splits into two arms that wrap around and shape the Tri-Valley, the developed I-680 corridor, and the burgeoning population along Highway 4. The western arm includes natural areas centered on the Briones Hills Agricultural Preserve, the Las Trampas/Buckhorn Canyon watershed, and the Pleasanton Ridgelands, linked together by narrow and tenuous connections. The eastern arm includes the Mount Diablo uplift and the mountains that connect via Altamont Pass to the Mount Hamilton portion of the Ridgelands.

The Ridgelands contain extensive oak woodlands, including blue and live oak and buckeyes. Higher elevations include California gray, coulter and ponderosa pine. Bay laurel, vine maple and willows crowd into the damper valleys and hillsides, brushy chaparral covers portions of the dryer landscape, especially in the south, and annual grasses (both native and European) blanket exposed slopes throughout the range.

This extensive natural area supports mountain lion, bobcat, kit foxes, eagles, hawks, tule elk, endangered red-legged frog and Alameda whipsnake, and a long list of other mammals, amphibians, reptiles and birds.

The landscape is generally too rugged and dry to support most agricultural uses, but is well suited to grazing. Native Americans managed this area through burning to create and sustain oak woodland optimized for acorn production and large game. The introduction of cattle grazing in the mid-1800's altered the mix and numbers of animals and plants residing in the Ridgelands, but management of the area over the past 150 years as range land has also ensured the continuation of its essential natural characteristics.

Public outdoor recreation is permitted in many parts of the Ridgelands. In Alameda and Contra Costa Counties, public access is permitted on approximately 90,000 acres of land owned and managed by the East Bay Regional Park District. Henry Coe State Park provides public access in the heart of the southern Ridgelands, south and east of Mount Hamilton, and Mount Diablo State Park provides access to and around this landmark in the north.

The Working Group

The Diablo Ridgelands Working Group is composed of those public agencies and non-profit organizations that have a role in protecting and managing the Diablo Ridgelands. The objective of the working group is to strengthen and enhance the individual efforts of the members of the Working Group, and to help ensure that these individual efforts complement and support each other in preserving the Ridgelands as an integrated and healthy landscape.

The Working Group adheres to the following principles:

1. Participation in the Working Group is voluntary, and decisions are based on consensus.
2. The focus of the Working Group is on non-regulatory techniques involving willing participation by landowners, public agencies and non-profit organizations.
3. Individual participants in the Working Group maintain their independent missions, objectives and activities. These individual responsibilities and rights are not limited or altered by what may be supported or advocated by the Working Group.
4. The Working Group is not organized to develop or advocate for or against modifications to County and City General Plans, Specific Plans or Zoning Ordinances, or state and federal regulatory standards.

The Potential

Despite increasing development threats, the unique, dramatic and productive character of the Diablo Ridgelands can still be preserved for future generations, as an extensive and connected landscape with high natural, scenic, ranching and recreational values,. Working together, public knowledge and appreciation of the Ridgelands can be raised. The cooperative efforts of the partners in the Working Group can enhance opportunities to attract outside funding to the area, and optimize the effectiveness of the partners individually and collectively to protect and manage the area's resources and uses.

Above all else, the Diablo Ridgelands can remain an interconnected, healthy ecosystem, both wild and productive, to be passed on to those who come after us, as a premier example of our heritage.

For more information, please contact Bettina Ring, Executive Director, at <bettina@openspacecouncil.org>.