Research
Flora of the Tejon Ranch Conservancy Acquisition Areas, Tejon Ranch, California (July 2010)
By David Magney Environmental Consulting
In early 2009 the Conservancy retained David Magney Environmental Consulting (DMEC) to conduct botanical surveys of the five Acquisition Areas (62,000 acres total area – Figure 1) on Tejon Ranch to provide a better understanding of the baseline conditions of these areas. These surveys were conducted during the spring and summer of 2009, representing 43 person-days of field effort, and the report was delivered in February 2010.
DMEC identified 668 plant taxa (species, subspecies, and varieties of plants) within the five Acquisition Areas. Of the 668 species identified, 572 (86%) are native and 96 (14%) are nonnative. The observed percentage of native species of the Acquisition Area flora is considerably higher than that of California as a whole, which has over 20% non-native species in its flora. Plant species documented within the individual Acquisition Areas is a follows: 286 species in White Wolf, 313 species in Old Headquarters, 228 species in Michener Ranch, 378 species in Bi-Centennial, and 243 species in Tri-Centennial. Of course, many of these species occur in multiple Acquisition Areas.
Sixteen special-status plant species were detected by DMEC (Table 1). Of the 16 special-status plants, two are listed as threatened or endangered by the state and/or federal governments and the California Native Plant Society (CNPS) as a List 1B species (Bakersfield cactus and striped adobe lily), five are CNPS List 1B, and the remaining nine are CNPS List 4. CNPS List 1B species are plants that are considered rare, threatened, or endangered in California and elsewhere while CNPS List 4 species are plants of limited distribution. All of the most sensitive species are found in the White Wolf and Old Headquarters Acquisition Areas on the San Joaquin Valley side of the Ranch.
Table 1. Special-Status Plant Species Documented in the Tejon Ranch Acquisition Areas
Status (CDFG 2010) |
Scientific Name |
Common Name |
Endangered/ Endangered/ 1B.1 |
Opuntia basilaris var. treleasei |
Bakersfield cactus |
None/ Threatened/ 1B.1 |
Fritillaria striata |
Striped adobe lily |
None/ Rare/ 1B.2 |
Deinandra arida |
Red rock tarplant |
None/ None/ 1B.1 |
Eschscholzia lemmonii ssp. kernensis |
Tejon poppy |
None/ None/ 1B.1 |
Layia leucopappa |
Comanche point tidy tips |
None/ None/ 1B.1 |
Navarretia setiloba |
Piute mountain pincushion plant |
None/ None/ 1B.2 |
Mimulus pictus |
Calico monkeyflower |
Delisted/ None/ 4.2 |
Eriastrum hooveri |
Hoover woolly star |
None/ None/ 4.2 |
Convolvulus simulans |
Small flowered morning glory |
None/ None/ 4.2 |
Microseris sylvatica |
Sylvan scorzonella |
None/ None/ 4.2 |
Perideridia gairdneri ssp. gairdneri |
Gairdner yampah |
None/ None/ 4.2 |
Trichostema ovatum |
San joaquin bluecurls |
None/ None/ 4.3 |
Delphinium parryi ssp. purpureum |
Mount piños larkspur |
None/ None/ 4.3 |
Perideridia pringlei |
Adobe yampah |
None/ None/ 4.3 |
Syntrichopappus lemmonii |
Lemmon's syntrichopappus |
None/ None/ 4.3 |
Thermopsis californica var. argentata |
Silvery false lupine |
CNPS List 1B: Rare, threatened, or endangered in California and elsewhere
CNPS List 4: Plants of limited distribution – a watch list
DMEC’s identified 34 vegetation alliances (communities) that are recognized alliances per the California Department of Fish and Game’s (CDFG) 2009 List of California Vegetation Alliances or A Manual of California Vegetation (Sawyer et al. 2009) within the five Acquisition Areas. Of the 34 vegetation alliances identified by DMEC, 10 are forest and woodland communities, 12 are shrubland communities, and 12 are herbaceous communities. DMEC considers the herbaceous alliances to be the most floristically rich and varied among the three general forms (i.e., woodlands, shrublands, and herblands). Because of the dominance by annual plants, the forb alliances can shift dramatically within a location over time. For example, White Wolf in mid-March was dominated almost exclusively by native annual forbs, but due to the spring’s drying effects, by mid-April native forbs were often undetectable and nonnative annual grasses dominated.
The botanical information generated by DMEC will be used by the Conservancy to develop Baseline Conditions Reports for the Acquisition Areas, describing the resources that will be protected by the conservation easements. This information also provided the Conservancy with a general sense of the various types of vegetation communities that will need to be addressed in the Initial Ranch-wide Management Plan (RWMP). For example, DMEC found 12 recognized herbaceous communities in the Acquisition Areas, illustrating the high diversity of grassland communities on the Ranch. Grasslands will be a focus of the grazing management element of the RWMP, and these different grassland communities may potentially respond differently to grazing management. The basic understanding of vegetation community diversity provided by the DMEC report leads the Conservancy to conclude that we will require more information on the types and distributions of these habitat types in order to prepare an effective RWMP.
