Chapter 11 - ACECs
Valley Management Area

Carrizo Plain

This ACEC includes approximately 199,030 federal surface acres located almost entirely in southeastern San Luis Obispo County. The area is located approximately 50 miles southwest of Bakersfield and 50 miles southeast of San Luis Obispo. This ACEC includes the Carrizo Plain, Elkhorn Plain, portions of the Temblor Mountain Range and the Caliente Mountain Range, which are known collectively as the Carrizo Plain Natural Area.

Page 121 

The Carrizo Plain Natural Area (CPNA), lying adjacent to the southwest edge of the San Joaquin Valley in eastern San Luis Obispo County, is the largest remaining tract of the San Joaquin valley biogeographic province with limited evidence of human alteration. The 253,628 acre area is a diverse complex of habitats with very limited distribution in their former range. It includes the largest remaining contiguous habitats for many endangered, threatened and rare species such as the San Joaquin kit fox, blunt-nosed leopard lizard, giant kangaroo rat, and San Joaquin antelope squirrel and supports some of the healthiest populations of these species. The CPNA also provides habitat for many plant species including the California jewelflower, Hoover's wooly-star and San Joaquin wooly-threads, all listed as endangered or threatened. Recently the CPNA has been a focal point identified in Recovery Plans for land acquisition and management of these species. In addition, the CPNA contains habitat for California condors as well as pronghorn antelope, tule elk, sandhill cranes and mountain plovers. A wide variety of raptor species also use the area for nesting, foraging and wintering. Separated from the San Joaquin valley floor by the Temblor Range, the size, resource values, isolation, and relatively undisturbed nature of this region distinguish it as ideal for an ACEC Area that promotes the long-term conservation of the vanishing San Joaquin flora and fauna.

In addition to its biological wealth, the area has significant archaeological and historical resources as evident by physical remains found dispersed across the landscape. Human prehistory of the Carrizo Plain probably began near the end of the Pleistocene as suggested by nearby Paleo-Indian Period (circa 11,000 - 9,000 B.C.) sites located at Tulare Lake, Buena Vista Lake, and the Tehachapi Mountains. Bedrock mortar milling features and elaborate pictographs are primary manifestations of prehistoric occupation of the area. Ethnographic information for this region of California is not well defined but research indicates that the Carrizo Plain is near the interface of three different cultural affiliations, the Chumash, the Southern Valley Yokuts, and the Salinan. The historical period (AD 1769) began in this region of California with the arrival of Europeans during the Spanish Colonial era, followed by the Mexican Republic, the California Republic, and the United States eras. The historic past is recognized today by remains associated with livestock operations, dryland farming, and ranching facilities.

The geological structure and the processes that continue to form it are unique and also of great interest. Geomorphic features of the San Andreas Fault are exceptionally well displayed and are often depicted in books, magazines, and newspaper articles. Increasing interest in earthquake activities bring people from around the world; both amateur enthusiasts and research geologists with government agencies and universities come to study the San Andreas Fault.

Efforts to protect these and other resources began in 1984 when the BLM's Coast-Valley RMP established three Areas of Critical Environmental Concern (ACEC). These included Soda Lake (2,970 acres), the Elkhorn Plain (8,600 acres) and the San Andreas Fault Scarp (1,120 acres). The first two ACECs were primarily established to protect habitat and species. The San Andreas Fault Scarp ACEC was established to protect the surface expressions of the fault. It is recommended that these three ACECs be included within a larger ACEC encompassing the entire CPNA. This would be referred to as the CPNA Area of Critical Environmental Concern.

The primary intent of the ACEC is to conserve the biological integrity of the CPNA. Biological integrity includes the concept of biological diversity, defined as the variety and variability among living organisms and the ecological complexes in which they occur, and the occurrence of all ecological processes at appropriate rates. In other words, the CPNA will exhibit high biological integrity if it conserves the complete spectrum of integrated, adaptive indigenous species and communities subject to natural evolutionary and biogeographic processes. These ideas reflect the managing partners decision to manage for the entirety of biodiversity and not solely on a few species.

Large numbers of a single species may be attained if intensive management scenarios designed solely to maximize the numbers of that species are implemented over large areas, yet the intent of the managing partners is not to maintain spurious or incomplete ecosystems in this way. Maintaining artificially high densities of a species may increase the likelihood of local extinctions due to resource depletion, disease outbreaks, and extreme population fluctuations and crashes. Conversely, allowing a native, listed, or primary management species to reach extremely low levels also raises the likelihood of local extinction. The managing partners have

Page 122 

determined that maintaining self-sustaining populations of listed species within the framework of biological integrity is the best the CPNA can do to contribute to recovery. Operating under these principles, we hope to allow a functioning system to help define and maintain healthy self-sustaining populations of the full spectrum of indigenous species; including endangered and threatened species through natural evolutionary processes, thereby eventually minimizing the need for direct human intervention.

Within this framework, however, there exists potential for conflict between balancing the immediate need for endangered species recovery, mandated by the Endangered Species Act, and the needs of other elements and processes. For instance, intensive land management, such as high grazing pressure, may be considered necessary for maintaining some listed species populations even though it could be detrimental to other species and ecosystem process. Nevertheless, continuing intensive management of some areas may at times be necessary until it can be determined how best to integrate them into the management of biological integrity overall. Continuing intensive habitat management for listed species that interferes with other native species or ecosystem processes should therefore be considered a temporary emergency measure. The extent of this intensive management will be determined by evaluating factors such as the risk of no action, time and budget constraints, severity of management needed, severity of detriment to other species and communities, and the amount of space required for security.

The Carrizo Plain Natural Area clearly meets the relevance and importance criteria established for ACECs.

Objective     Manage the CPNA so that indigenous species interact within a dynamic and fully functioning system in perpetuity while conserving unique natural and cultural resources and maintaining opportunities for compatible scientific, cultural, social and recreational activities. This will be done in part by:

- restoring degraded natural systems and emphasize natural processes in management practices;

- managing human activities to protect natural and sensitive resources;

- promoting public participation in educational and management activities to foster an understanding of and support for the CPNA's resources, mission, and role in conserving our Natural Heritage for the future.

Management Prescriptions

Implement the Carrizo Plain Natural Area Management Plan.

Soda Lake and the surrounding wetlands shall be proposed for withdrawal from entry under the mining laws.

The ACEC is open for the leasing of oil, gas, and geothermal resources subject to the following special stipulations: LSU - Protected Species, LSU - Sensitive Species and LSU - Raptors.

Camping is restricted to designated locations.

Portions of the ACEC are available for livestock grazing and are currently allotted. All authorized livestock grazing within the ACEC shall be managed to foster restoration and enhancement of plant communities and listed plant and animals species only, not to establish federal grazing preference. Portions of the ACEC are unavailable for livestock grazing due to other resource concerns.

Support Actions

Support actions are described in the Carrizo Plain Natural Area Management Plan.

Page 123 

Legal Description

The following description of the Carrizo ACEC boundary encompasses approximately 143,300 acres of Federal surface and subsurface, 55,730 acres of Federal surface only and an estimated 10,880 acres of Federal minerals.

T. 30 S., R. 19 E., MDB&M
Sec. 31 NW¼NE¼, S½NE¼, E½NE¼NW¼, SE¼
Sec. 32 S½NW¼ (except that portion conveyed to Dewey E. Werling by deed recorded November 27, 1970, in Book 1595, Page 36 of Official Records),and the S½
Sec. 33 SW¼SW¼
Sec. 35 All (except those portions within units 14 and 18 of California Valley)

T. 30 S., R. 20 E., MDB&M
Secs. 8-10, 15-16, 21-28,32 - 36
Sec. 14 W½, SE¼

T. 30 S., R. 21 E., MDB&M
Sec. 29 SW¼
Sec.30 Lots 1-12 E½SW¼,SE¼
Secs. 31, 32

T. 31 S., R. 19 E., MDB&M
Secs. 1-5, 9-15, 2-27, 35 - 36
Sec. 6 E½E½
Sec. 8 NE¼

T. 31 S., R. 20 E., MDB&M
Secs. 1 - 36

T. 31 S., R. 21 E., MDB&M
Secs. 4 - 9, 16 - 22, 26 - 36
Sec. 10 SW¼
Sec. 15 W½, SE¼
Sec. 23 W½, SE¼
Sec. 25 W½, SE¼

T. 31 S., R. 22 E., MDB&M
Sec. 31 Lots 2 - 15

T. 32 S., R. 19 E., MDB&M
Secs. 1, 12, 25
Sec. 2 E½
Sec. 13 NE¼

T. 32 S., R. 20 E., MDB&M
Secs. 1 - 18, 20 - 36
Sec. 19 NE¼, S½

T. 32 S., R. 21 E., MDB&M
Secs. 1 - 36

T. 32 S., R. 22 E., MDB&M
Sec. 4 SW¼
Secs. 5 - 8, 15 - 23, 25 - 36
Sec. 9 W½, SE¼
Sec. 10 SW¼
Sec. 14 SW¼
Sec. 24 S½

T. 32 S., R. 23 E., MDB&M
Sec. 30 Lots 1 - 8
Sec. 31

T. 10 N., R. 24 W., SBB&M
Secs. 4 - 8, 17 - 18
Sec. 9 N½, SW¼, W½SE¼
Sec. 19 NE¼

T. 10 N., R. 25 W., SBB&M
Secs. 1 - 13

T. 10 N., R. 26 W., SBB&M
Secs. 1 - 6, 11 - 12

T. 10 N., R. 27 W., SBB&M
Secs. 1 - 3

T. 10-1/2 N., R. 26 W., SBB&M
Secs. 31 - 36

T. 10-1/2 N., R. 27 W., SBB&M
Secs. 34 - 36

T. 11 N., R. 24 W., SBB&M
Sec. 7 Lots 1 - 4, E½W½
Secs. 18, 19, 28 - 33

T. 11 N., R. 25 W., SBB&M
Sec. 1 S½
Secs. 2 - 36

T. 11 N., R. 26 W., SBB&M
Secs. 1 - 36

T. 11 N., R. 27 W., SBB&M
Secs. 1 - 36

T. 11 N., R. 28 W., SBB&M
Secs. 1 - 4, 9 -16, 22 - 26
Sec. 5 Lots 1 - 3, 5 - 8, S½NE¼, SE¼NW¼, NE¼SW¼, N½SE¼

Sec. 8 Lots 1 - 4, and that portion of the Cuyama Rancho conveyed to the United States of America by deed recorded January 18, 1988 in Book 3101 Page 665 of the Official Records of San Luis Obispo county and Document # 5694 of the Official Records of Santa Barbara county

Sec. 17 Lots 1, 2, and that portion of the Cuyama Rancho conveyed to the United States of America by deed recorded January 18, 1988 in Book 3101 Page 665 of the Official Records of San Luis Obispo county and Document # 5694 of the Official Records of Santa Barbara county.

T. 12 N., R. 25 W., SBB&M
Secs. 31 - 34

T. 12 N., R. 26 W., SBB&M
Secs. 31 - 36

T. 12 N., R. 27 W., SBB&M
Secs. 31 - 36

T. 12 N., R. 28 W., SBB&M
Sec. 32 Lots 1 - 3, NE¼SW¼, SE¼
Secs. 33 - 36

Area Map

Page 124 

Return to Chapter 11- Area of Critical Concern

Return to Table of Contents