Conservation Assessment of —Tejon Ranch— © 2003 Andrew M. Harvey www.visualjourneys.net December 2003 Conservation Assessment of —Tejon Ranch— Prepared by Jerre Ann Stallcup Michael D. White James R. Strittholt Wayne D. Spencer Prepared for Preserving Wild California Resources Legacy Fund Foundation (Grant #2003-0116) December 2003 The Conservation Biology Institute provides scientific expertise to support conservation and recovery of biological diversity in its natural state through applied research, education, planning, and community service. Conservation Assessment of Tejon Ranch Table of Contents Page Acknowledgements iv Executive Summary v Introduction 1 Objectives 1 Process 2 Refining Land Cover Data for Tejon Ranch 4 Assessing Conservation Values of Tejon Ranch 6 Habitat connectivity 6 Listed and endemic species 7 Watershed integrity 9 Unique, diverse, and under-conserved vegetation communities 15 Roadless areas 17 Summary of results 19 Regional Conservation Planning 21 Landscape units 21 Threats 26 Reserve design considerations 26 Suggested conservation goals 26 Conclusions 29 References 30 Appendices A—Land Cover Classification and Roads A-1 B—Assessing Conservation Values B-1 ii December 2003 Conservation Assessment of Tejon Ranch List of Tables Page Table 1 Conservation values by landscape unit 23 List of Figures Page Figure 1 Geography of Tejon Ranch 2 Figure 2 Land cover on Tejon Ranch 5 Figure 3 Linkage design for the Tehachapi connection 8 Figure 4a Potential habitat for listed plant species 10 Figure 4b Potential habitat for endemic plant species 11 Figure 4c Potential habitat for selected amphibians and reptiles 12 Figure 4d Potential habitat for four mammal species 13 Figure 4e Potential habitat for California spotted owl and Critical Habitat for California condor 14 Figure 5 Watershed basins and watershed integrity 16 Figure 6 Under-protected vegetation communities and habitat diversity 18 Figure 7 Roadless areas on Tejon Ranch 20 Figure 8 Landscape units on Tejon Ranch 22 Figure 9 Satellite image of Tejon Ranch and vicinity 27 iii December 2003 Conservation Assessment of Tejon Ranch Acknowledgements We are grateful to Kristeen Penrod and Clint Cabañero, South Coast Wildlands Project, for sharing the final linkage design and species model criteria from the South Coast Missing Linkages Project (Tehachapi landscape linkage, Penrod et al. 2003). We also thank photographer Andrew Harvey for use of his photos to help interpret vegetation signatures on satellite imagery, and David Clendenen, Ellen Cypher, and David Wake for biological information used in the analyses. This study was funded by grant #2003-0116 made through the Preserving Wild California (PWC) program of the Resources Legacy Fund Foundation. We thank Ed Hastey, Kristen LaVine, and others at the Foundation for supporting our work. iv December 2003 Conservation Assessment of Tejon Ranch Executive Summary Tejon Ranch supports a multitude of irreplaceable biological resources, and the melding of these resources in one large, intact landscape makes the Ranch a regionally significant conservation target. Comprehensive land use planning is needed for this keystone property, which is surrounded by growing metropolitan and agricultural areas—the Los Angeles basin, Bakersfield and the San Joaquin Valley, Tehachapi and Cummings valleys in the Tehachapi Mountains, and Antelope Valley of the Mojave Desert. The cumulative effects of conservation and development in this region must be evaluated as part of designing a functional, landscape-scale reserve for Tejon Ranch. Understanding the distribution of conservation values on the Ranch and surrounding areas is critical to inform conservation design for the region. This report evaluates the distribution of conservation values on Tejon Ranch, as an incremental step towards developing a regional reserve design. We used publicly available data and science-based conservation principles to describe and map selected conservation values for Tejon Ranch. Our assessment demonstrates that, although different areas of the Ranch support different sets of conservation values, virtually all areas of the Ranch support one or more sets of values. To spatially describe the distribution of these values on Tejon Ranch, we identified four landscape units that differentially support the conservation values considered in our analysis: A. Lowland grasslands and oak savannas of the San Joaquin Valley (108,244 acres) o Last remaining connection between grasslands on the east and west sides of the San Joaquin Valley o Potential habitat for 5 listed plants, 5 listed animals, and 4 endemic plants considered in this analysis o Almost 100,000 acres of grassland and oak savanna communities, which are under-represented regionally in protected open space B. Closed-canopy oak woodland, montane hardwood, and montane hardwood-conifer communities on the northwest slope of the Tehachapi Mountains (81,836 acres) o Irreplaceable landscape linkage and habitats for foothill and montane species between the Sequoia and Los Padres National Forests o 58,000 acres of the highest integrity watershed basins o 74,500 acres of the highest diversity of vegetation communities on the Ranch o 63,578 acres of roadless areas, including the largest area of roadless habitat >10,000 acres on the Ranch o Potential habitat for 3 listed animal species considered in this analysis v December 2003 Conservation Assessment of Tejon Ranch C. Oak woodland, chaparral, and pinyon-juniper communities on the southeast slope of the Tehachapi Mountains (26,518 acres) o Irreplaceable landscape linkage and habitats for foothill and montane species between the Sequoia and Los Padres National Forests o High integrity watershed basins (60% of unit) o High diversity of vegetation communities (87% of unit) o Over 20,000 acres of roadless areas, including 7,800 acres of roadless habitat >10,000 acres o Potential habitat for 2 listed animals and 2 endemic animals considered in this analysis D. Lowland Joshua tree woodland, grassland, and desert scrub communities of the Mojave Desert (53,613 acres) o Landscape linkage and habitats for lowland and desert species o Over 25,000 acres of grasslands, which are under-represented regionally in protected open space o Over 25,000 acres of roadless habitat (almost half of the unit) o Potential habitat for 1 listed animal and 2 endemic animals considered in this analysis Reserve designs for Tejon Ranch must, at a minimum, capture these values while ensuring the maintenance and management of ecological processes within and between landscape units. Similarly, conservation planning must ensure integration and connection of these landscape units with others in the region, along with a regional plan for long-term management and biological monitoring. Without careful and comprehensive consideration, land use plans for Tejon Ranch could irretrievably alter the biological functions and values of this keystone landscape. vi December 2003 Conservation Assessment of Tejon Ranch Introduction Tejon Ranch is a 270,000-acre private property located in the Tehachapi Mountains and including portions of the adjacent San Joaquin and Antelope valleys (Figure 1). A previous assessment of the region (White et al. 2003) demonstrated that the Ranch comprises a unique and diverse biological core area with high habitat integrity, intact, functioning watersheds, and significant roadless areas. Conservation of Tejon Ranch is critical to ensuring landscape connectivity between the Sequoia National Forest and the Los Padres National Forest, and significant conservation on the Ranch is crucial to ensuring that these and other existing conservation investments in the region remain intact and functional (Penrod et al. 2003). The Ranch meets virtually all of the California Resources Agency priority criteria for conservation, as described by the California Legacy Project (2002). Comprehensive land use planning is needed to effectively conserve the irreplaceable natural resource values of Tejon Ranch. This study uses publicly available data and science-based conservation principles to describe and map selected conservation values for Tejon Ranch, as an incremental step towards developing a regional conservation reserve design. This study recognizes that conservation design is a systematic, iterative, and adaptive process that benefits from peer review and public comment. The major premises of this study are: • Tejon Ranch supports a multitude of irreplaceable biological resources. The melding of these resources in one large, intact landscape makes the Ranch a regionally significant conservation target (White et al. 2003, Penrod et al. 2003). • Reserve design is the process of optimizing the capture of multiple biological values in an effective and sustainable configuration. Various factors influence the strategic decisions that guide the reserve design process, such as regional conservation priorities, threats to resource values, conservation opportunities, and available conservation mechanisms. • Understanding the distribution of resource values is critical to informed conservation design. Objectives The objectives of this study were to: 1. Identify the spatial distribution of various conservation values on Tejon Ranch. 2. Illustrate how the distribution of different conservation values can influence reserve design. 3. Identify landscape units on Tejon Ranch and describe how each captures unique and diverse conservation values. 4. Identify strategic decisions that influence implementation