Part 1: Landscape View
There’s an extraordinary natural area in the east Livermore hills six miles south of the Altamont Pass wind turbines as the hawk flies. It’s called Tesla Park by those who want to preserve it and the Alameda-Tesla Expansion Area by California State Parks. It’s a natural and cultural resource preserve to those who want to protect it, and a future off-highway vehicle recreation area to State Parks.
Tesla is at the north end of the Diablo Range, a 150-mile series of isolated inland hills, valleys, and mountains within the larger South Coast Range. Writer Eric Simons describes the Diablo Range in depth in the Spring 2020 issue of Bay Nature, calling it “a vast unconnected swath east and south of San Francisco Bay, extending all the way down to Kern County.”
Few have the opportunity to walk Tesla; it is currently closed to visitors. If you were fortunate enough to experience it—and we hope everyone can someday—you would likely be taken in by its expansive views and topography of rolling hills dotted with native oaks and a myriad of native shrubs, forbs, and grasses, many of which are rare. Ephemeral Corral Hollow creek cuts though steep canyons within the 3,100-acre property.
Tesla’s peaceful landscape contrasts starkly with the adjacent property, Carnegie State Vehicular Recreation Area. California State Parks owns Carnegie and bought the Tesla property for future expansion of the off-highway motor vehicle park. Plans for the expansion include an off-road vehicle trail system and a 4×4 vehicle obstacle course. Conservation advocates who studied the expansion plans identified devastating impacts if off-highway vehicle use were allowed on the unique and fragile Tesla landscape. An alliance to save Tesla, Friends of Tesla Park, has been developing proposals for an alternative use plan to preserve Tesla’s historical, cultural, biological, and scenic resources, and it has the support of many agencies, organizations, and individuals.
Tesla’s ecological richness derives in part from its unique location, a feature noted in a scientific consensus statement, “Ecological Value of the State Parks’ Alameda-Tesla Expansion Area,” signed by 48 ecologists and university scientists. Tesla straddles the moist Coast Range and the northern edge of the San Joaquin Desert, a geographic interface that influences the “unique species assemblages as well as evolutionary differentiation within species.”
Dr. Bruce Baldwin, curator of the Jepson Herbarium and professor of botany at UC Berkeley, and one of the consensus statement signatories, notes the Tesla property’s “unusual array of vegetation types, including rare assemblages such as desert olive shrubland.” He observed that “grasslands there are highly diverse in native forbs and native grasses, as is the understory of blue oak woodland.…It is no surprise that such habitat integrity and diversity is also reflected by the richness of native animal life there.”
Three of California’s influential early naturalists—Joseph LeConte, Joseph Grinnell, and John Muir—recognized the conservation value of the Corral Hollow watershed where Tesla is located, and its importance as a unique natural area has only increased since then. Our CNPS East Bay chapter recognizes Corral Hollow as one of 15 Botanical Priority Protection Areas (BPPAs) within Alameda and Contra Costa counties. BPPAs are areas of rich native plant diversity that are threatened by current or potential land use decisions. BPPA guidebook contributor Erin McDermott observed that desert species such as desert olive (Forestiera pubescens) and shredding evening-primrose (Eremothera boothii ssp. decorticans) overlap in the Corral Hollow area with “South Coast Range stalwarts” such as big tarplant (Blepharizonia plumosa), a tall annual that scents the air with fragrant terpenoid compounds.
This varied landscape supports a number of sensitive botanical features recognized by the California Department of Fish and Wildlife: 13 special status plants and at least seven sensitive natural communities. In addition, CNPS East Bay’s rare plant inventory for Alameda and Contra Costa counties lists over 200 rare and unusual plants from the Corral Hollow area, including big tarplant and Hospital Canyon larkspur (Delphinium californicum ssp. interius).
Tesla’s unique location in the Diablo Range, along with its geology and topography, has greatly influenced its cultural and economic history, native plant diversity, and important role as a critical wildlife corridor. In our next segment on Tesla, we will draw from a few stories about the area’s rich history and ecology. We also invite you to learn more about Tesla and the effort to preserve it on the Save Tesla Park website, as well as at SaveTeslaPark on Facebook, and @tesla_park and #SaveTeslaPark on Twitter.
This is the first in a five-part series of articles exploring the diverse and sensitive ecosystem of Tesla, a 3,100-acre property in Corral Hollow canyon on the eastern edge of Alameda County. Our series starts with an overview of Tesla’s landscape and some of the factors that contribute to its importance as habitat for plants and wildlife. Later, we will provide views into Tesla’s cultural and economic history, native plant diversity, and role as a critical wildlife corridor. Finally, we will address the threats to Tesla’s ecological richness posed by California State Parks’ plan to open the Tesla property to off-highway vehicle use, and we’ll highlight the ongoing effort to protect Tesla as a natural history preserve.
— Joanna Garaventa, CNPS East Bay Conservation Analyst, and Jim Hanson, Conservation Committee Chair