Appendix SW. The Southwestern California Region

Ten percent of the region was mapped as status 1 or 2 managed areas (Table SW-1). (Note: this slight increase from 9.8% reported previously [Beardsley and Stoms 1993, Davis et al. 1995] was caused be minor recent revisions in the stewardship coverage, primarily 1) the designation by the California Desert Protection Act of 1994 of portions of 3 new wilderness areas managed by BLM along the eastern edge of the region, and 2) the reclassification from three levels to the standard four levels for GAP). The area of status 1 and 2 managed areas is dominated by USFS Wilderness Areas. State park units, including reserves and wilderness areas, are the second largest category. In addition, BLM administers several ACECs and wilderness areas.

Status	Area (km²)	%
1	2,707	8.0
2	670	2.0
3	9,217	27.2
4	21,239	62.8
Total	33,833	100.0

Lands below 500 m elevation account for nearly half of the region, yet the proportion that is managed for biodiversity is exceptionally small (Figure SW-3). Lower elevations are predominately private land and intensively converted to urban and agricultural use. In contrast, lands above 1000 m have a disproportionate share of the biodiversity management areas. Mid-elevations, between 1500 and 2500 meters are primarily public lands, with about 25 percent being status 1 or 2 management, but most being classified as status 3. More than 90 percent of the highest elevation zone is in status 1 management (usually National Forest wilderness areas).

CNDDB Code	CNDDB Community Name	CNDDB Rank	Status 1 %	Status 2 %	Status 3 %	Status 4 %	Total Mapped Distribution (km²)	Status 1+2 %
31200	Southern Coastal Bluff Scrub	S1.1	0.0	13.9	0.5	85.6	22.6	13.9
32300	Venturan Coastal Sage Scrub	S3.1	2.3	4.1	9.3	84.2	1,470.8	6.4
32500	Diegan Coastal Sage Scrub	S3.1	4.0	1.8	27.6	66.6	1,316.9	5.8
32700	Riversidian Sage Scrub	S1.1/3.1	3.7	3.6	19.5	73.2	744.3	7.3
34100	Mojave Creosote Bush Scrub	S4	17.5	4.8	48.2	29.4	88.2	22.3
35100	Great Basin Mixed Scrub	S4	28.5	0.0	21.7	49.8	34.4	28.5
35210	Big Sagebrush Scrub	S4	6.1	2.2	50.2	41.5	335.5	8.3
35500	Cercocarpus ledifolius woodland *	NR	92.1	0.0	0.2	7.8	2.1	92.1
37110	Northern Mixed Chaparral	S4	5.3	1.4	47.8	45.4	1,173.7	6.7
37120	Southern Mixed Chaparral	S3.2/3.3	2.1	1.7	18.8	77.5	219.4	3.8
37200	Chamise Chaparral	S4	9.7	1.6	27.4	61.3	1,431.7	11.3
37300	Red Shank Chaparral	S3.2	5.6	4.9	37.3	52.2	957.2	10.5
37400	Semi-Desert Chaparral	S3.2	11.6	6.4	49.6	32.4	1,252.9	18.0
37510	Mixed Montane Chaparral	S4	45.9	3.0	39.5	11.6	186.0	48.9
37520	Montane Manzanita Chaparral	S4	2.8	2.2	57.8	37.1	13.7	5.1
37530	Montane Ceanothus Chaparral	S4/3.3	9.9	1.3	57.5	31.3	357.3	11.2
37810	Buck Brush Chaparral	S4	13.9	2.8	37.8	45.5	716.8	16.7
37830	Ceanothus crassifolius Chaparral	S3.2	14.6	0.9	46.5	38.0	2,091.1	15.5
37840	Ceanothus megacarpus Chaparral	S3.2	1.3	17.3	24.9	56.5	578.9	18.6
37900	Scrub Oak Chaparral	S3.3	20.7	0.9	53.0	25.5	1,660.7	21.6
37A00	Interior Live Oak Chaparral	S3.3	24.5	0.6	59.8	15.2	1,189.7	25.1
37B00	Upper Sonoran Manzanita Chaparral	S4	3.7	2.6	67.9	25.8	388.8	6.3
37E00	Mesic North Slope Chaparral	S3.3	58.6	2.7	37.6	1.1	14.6	61.3
37G00	Coastal Sage-Chaparral Scrub	S3.2	0.1	3.3	14.7	81.9	193.1	3.4
42110	Valley Needlegrass Grassland	S3.1	6.1	0.0	0.7	93.1	3.4	6.1
42200	Non-Native Grassland	S4	1.7	4.9	19.5	73.9	1,205.5	6.6
47000	Pavement Plain	S1.1	0.1	0.9	66.8	32.2	11.3	1.0
52120	Southern Coastal Salt Marsh	S2.1	21.6	12.1	16.6	49.6	11.0	33.7
52200	Coastal Brackish Marsh	S2.1	0.0	0.0	0.0	100.0	1.1	0.0
52410	Coastal and Valley Freshwater Marsh	S2.1	4.3	1.0	6.9	87.8	40.4	5.3
61310	Southern Coast Live Oak Riparian Forest	S4	16.2	0.0	45.6	38.1	26.0	16.2
61320	Southern Arroyo Willow Riparian Forest	S2.1	4.4	3.2	26.4	65.9	37.7	7.6
61330	Southern Cottonwood-Willow Riparian Forest	S3.2	1.6	5.8	44.8	47.8	59.9	7.4
61510	White Alder Riparian Forest	S4	17.1	0.0	35.7	47.1	8.4	17.1
62400	Southern Sycamore-Alder Riparian Woodland	S4	6.6	0.0	27.7	65.7	18.1	6.6
63310	Mule Fat Scrub	S4	2.5	8.3	27.8	61.4	45.8	10.8
63320	Southern Willow Scrub	S2.1	0.0	0.0	11.7	88.3	1.6	0.0
63330	Southern Alluvial Fan Scrub *	NR	0.0	0.0	2.3	97.7	13.2	0.0
71130	Valley Oak Woodland	S2.1	0.0	3.4	2.8	93.8	36.6	3.4
71140	Blue Oak Woodland	S3.2	0.0	0.0	10.5	89.5	4.9	0.0
71150	Interior Live Oak Woodland	S3.2	0.0	0.0	100.0	0.0	14.2	0.0
71160	Coast Live Oak Woodland	S4	0.8	1.4	24.6	73.2	60.4	2.2
71182	Dense Engelmann Oak Woodland	S2.1	3.2	0.3	20.7	75.9	234.8	3.5
71210	California Walnut Woodland	S2.1	0.4	2.5	8.4	88.7	58.5	2.9
71322	Non-Serpentine Foothill Pine Woodland	S4	0.0	0.0	0.0	100.0	4.9	0.0
71410	Foothill Pine-Oak Woodland	S4	0.0	0.0	24.4	75.6	10.0	0.0
72200	Mojavean Pinyon and Juniper Woodlands	S3.2/4	12.8	0.6	66.4	20.2	1,447.0	13.4
72300	Peninsular Pinyon and Juniper Woodlands	S3.2	71.1	1.5	5.6	21.8	14.8	72.6
81310	Coast Live Oak Forest	S4	6.3	1.7	14.9	77.1	175.7	8.0
81320	Canyon Live Oak Forest	S4	29.7	1.5	46.7	22.0	178.2	31.2
81330	Interior Live Oak Forest	S4	0.0	0.0	99.4	0.6	40.6	0.0
81340	Black Oak Forest	S4	6.6	9.5	48.2	35.7	208.9	16.1
83210	Knobcone Pine Forest	S4	0.0	0.0	91.8	8.2	5.1	0.0
83330	Southern Interior Cypress Forest	S2.1	0.0	7.2	70.3	22.4	17.8	7.2
84140	Coulter Pine Forest	S3.2	12.3	2.4	50.7	34.6	310.2	14.7
84150	Bigcone Spruce-Canyon Oak Forest	S3.2	46.6	0.1	45.7	7.6	320.4	46.7
84210	Westside Ponderosa Pine Forest	S2.1	38.4	5.5	30.6	25.5	322.5	43.9
84230	Sierran Mixed Coniferous Forest	S4	27.9	2.5	55.7	13.9	216.3	30.4
85100	Jeffrey Pine Forest	S4	21.9	0.2	65.1	12.7	235.2	22.1
85210	Jeffrey Pine-Fir Forest	S4	23.9	0.0	63.3	12.8	354.8	23.9
85320	Southern California White Fir Forest	S4	33.5	1.3	52.7	12.6	38.1	34.8
86100	Lodgepole Pine Forest	S4	51.7	0.0	34.6	13.7	4.7	51.7
86500	Southern California Subalpine Forest	S3.3	92.3	0.0	7.7	0.0	52.4	92.3
	Region Total - Natural Communities						22,370
	Region Total - All Lands		8.0	2.0	27.2	62.8	33,827	10.0

Based on the GAP classification of management status, communities restricted largely to the lower elevations , such as Non-Native Grasslands and coastal sage scrub types, are at considerable risk (Table SW-2). Roughly 88% of areas below 500 m are in status 4 management (i.e. primarily privately owned). A majority of the lands at these elevations have already been converted to agricultural or urban uses and most of the remaining lands are threatened with future urbanization. We summarize the data for widespread types (mapped distribution > 25 km²) in Table SW-2 in four categories of protection. A comparison of management status with the ranking of communities in the Natural Diversity Data Base indicated that communities with greater than 70% of their distribution in status 4 lands or less than 10% in status 1 and 2 lands are most vulnerable (Davis et al. 1995).

1. Plant community types occurring mainly on status 4 lands. Many of the community types characteristic of lower elevation areas near the coast fall into this category. Valley Needlegrass Grassland and Valley Oak Woodland were mapped with over 90% of their distribution on lands with essentially no formal protection. Other widespread types include Venturan Coastal (32300) and Riversidian (32700) Sage Scrub, Coastal Sage-Chaparral Scrub, Southern Mixed Chaparral, Non-Native Grassland, Coastal and Valley Freshwater Marsh, Coast Live Oak (both woodland and forest), California Walnut Woodland, and Dense Engelmann Oak Woodland.

2. Scrub, chaparral, and herbaceous types mainly located in unprotected areas. Many of the types listed in category 1 above, also have less than 10% of their area in status 1 or 2 lands: all four sage scrub types, Southern Mixed Chaparral, grasslands, and Coastal and Valley Freshwater Marsh. Big Sagebrush Scrub, Northern Mixed Chaparral, and Upper Sonoran Manzanita Chaparral are additions to the list.

3. Forest and woodland types mainly located in unprotected areas. Many of the tree-dominated community types listed in category 1 are repeated here as well, such as the oak types (Valley, Coast Live, and Engelmann) and California Walnut Woodland. Additional woodlands of note here are two riparian forests (Southern Cottonwood-Willow and Southern Arroyo Willow), Interior Live Oak Forest, and Southern Interior Cypress Forest, although the last type was only mapped over 17.8 km².

4. Community types that appear well-protected. Communities at higher elevations, especially montane chaparral and coniferous forest types, are generally well represented (> 25% in status 1 or 2 areas). Included are the montane forest types, several of which are more typical of other regions: Canyon Live Oak Forest, Bigcone Spruce-Canyon Oak Forest, Westside Ponderosa Pine, Sierran Mixed Coniferous, Jeffrey Pine-Fir, Southern California White Fir, and Southern California Subapline Forests. Another well-represented group are the desert types that are widespread in adjacent regions such as Mojave Creosote Bush Scrub and Great Basin Mixed Scrub.

We were unable to distinguish herbaceous plant species and community types beyond very general classes. For example, we classified practically all grasslands as "Non-native" despite the fact that many of these areas contain sizeable populations of native grasses and forbs. Thus our estimate of the extent of the Valley Needlegrass community is undoubtedly too low. Keeley (1990) provides a much more detailed assessment of the distribution and conservation status of native grasslands. However, we would call attention to the fact that nearly three-fourths of non-native grassland in the region is privately held, and only 6.6% is in status 1 or 2 areas. Although dominated by exotic species, these grasslands can be rich in native plant species and are habitat to many animal species. Recent efforts to preserve grassland habitats for the Stephens' kangaroo rat (Dipodomys stephensi) in the Riverside Basin attest the ecological significance of this community type. However, annual grasslands in other parts of the region are generally not considered a conservation priority. Our data suggest that from a regional perspective Non-Native Grasslands appear to be at risk.

All coastal sage scrub communities (or soft chaparral) occur predominantly on private lands. Soft chaparral in California is largely confined to this region, although variations with different species composition extend north along the coast to beyond the San Francisco Bay. Once very common and widespread, the type has been fragmented and its extent reduced severely by development of coastal habitats (O'Leary 1990). Much conservation effort is focused on areas in Orange, Riverside, and San Diego Counties that are habitat for the threatened California gnatcatcher (Polioptila californica) (Brussard and Murphy 1992). Our analysis highlights the need to consider more northerly elements as well. For example, practically all landscapes dominated by Salvia leucophylla are in the western Transverse ranges, north of the current range of the gnatcatcher.

Big Sagebrush Scrub, although widespread elsewhere in California, appears vulnerable in this region. Plant communities dominated by Artemisia tridentata, Chrysothamnus nauseousus or C. parryi occur along northern and northeastern margins of the region, and are concentrated in the upper Cuyama Valley, Lockwood Valley, eastern San Bernardino Mountains, locally in the Anza Valley, and in the extreme southeastern corner of the region. It appears that nearly all sagebrush scrub in the region is subject to grazing. Roughly 50% of the area occupied by sagebrush is multiple-use (status 3) public land, so conservation concern for this community can probably be adequately addressed by the public land managing agencies. Within the sagebrush community near Baldwin Lake in the northeastern San Bernardino Mountains, there is an edaphic community known as Pavement (or Pebble) Plains. These small plains, the remnants of a Pleistocene lake, are habitat to candidate endangered species such as Castilleja cinerea and Astragalus leucolobus, and to the greatest concentration of endemic plants in the state (Schoenherr 1992). Because this type occurs in patches below our minimum mapping unit, our assessment of its extent and land ownership and management patterns are only approximations. Nevertheless, this type appears to be deserving of more conservation research and management.

There are five major hardwood woodland types characteristic of this region. Coast Live Oak (Quercus agrifolia) is distributed throughout the region and in association with a number of other co-dominant species. Most communities types and the overall distribution of this species are poorly represented in protected areas, and conversion to urban land use appears to be one of the major causes of decline in these types (e.g., Scheidlinger and Zedler 1980). Quercus engelmannii is endemic to this region and is also significantly under-represented in status 1 and 2 areas. Recently Scott (1991) analyzed the geographic distribution of this species based on 1:24,000 maps that he prepared from air photos. He estimated that Q. engelmannii occurs over 31,500 ha, compared to our estimate of 23,480 ha. The discrepancy appears mainly due to the differences in map scale rather than classification, given that his mapped stands fall almost entirely within our mapped landscapes. Scott called attention to the poor representation of the species in existing reserves, a pattern that we also observed (3.5%), despite the recent establishment of significant new reserves such as The Nature Conservancy's Santa Rosa Plateau Reserve. Additional aquisitions, subsequent to the database compiled for CA-GAP, have extended the protection for this type to an unknown degree.

More localized woodland species include Quercus lobata, Quercus douglasii, Quercus wislizenii, Arbutus menziesii, and Juglans californica. While most of these species are more widely distributed in other regions of California, the southern California black walnut (var. californica) is almost entirely restricted to this region. The current distribution of this species is highly fragmented and reduced compared with its original distribution. It is almost entirely (89.3%) on private land, with remnant populations in the Santa Clara River drainage, Simi Hills, Santa Susana Mountains, Santa Monica Mountains, San Jose Hills, Puente Hills and Chino Hills. Quinn (1990) provides a detailed analysis of the distribution, ecology and conservation status of this type, and emphasizes the need for immediate conservation action in the face of iminent urbanization of many remaining habitats. Quercus chrysolepis, and to a lesser extent Quercus kelloggii, are widely distributed in the region and throughout California, and generally well represented in managed areas.

The various riparian woodland types are usually found in patches too small to be detected with the techniques employed by the GAP. Nevertheless some of these types appear to be poorly represented in biodiversity management areas.

Bigcone Spruce (Pseudostuga macrocarpa) and, to a lesser extent, Coulter Pine (Pinus coulteri) are largely restricted to and characteristic of this region. They generally occur between 500m and 1500m, but P. macrocarpa is concentrated in canyons and steep north-facing slopes, whereas P. coulteri occupies a range of topographic sites. Forty-seven percent of the mapped distribution of Bigcone Spruce-Canyon Oak Forest is in status 1 or 2 areas. Fifteen percent of the mapped distribution of Coulter Pine Forest is in protected areas.

Pinyon and Juniper Woodlands are prominant at the region boundaries adjoining the desert and Great Central Valley regions. They appear to be reasonably well represented and occur primarily on public lands.

Two endemic conifers, Cupressus forbesii , and C. arizonica ssp. arizonica are restricted to very local sites and difficult to detect using our methods. Both are worthy of conservation attention based on existing information (Oberbauer 1990).

CNDDB Code	CNDDB Community Name (Holland 1986)	% zoned for development	% zoned for agriculture	% zoned for open space or unknown
32300	Venturan Coastal Sage Scrub	19	1	80
32500	Diegan Coastal Sage Scrub	32	0	68
32700	Riversidian Sage Scrub	18	0	82
35210	Big Sagebrush Scrub	15	0	85
37120	Southern Mixed Chaparral	20	0	80
37B00	Upper Sonoran Manzanita Chaparral	2	0	98
37G00	Coastal Sage-Chaparral Scrub	32	0	68
42110	Valley Needlegrass Grassland *	0	7	93
42200	Non-Native Grassland	30	1	69
47000	Pavement Plain *	0	0	100
71130	Valley Oak Woodland	49	0	51
71160	Coast Live Oak Woodland	0	0	100
71182	Engelmann Oak Woodland	9	0	91
71210	California Walnut Woodland	34	0	66
81310	Coast Live Oak Forest	13	0	87
83330	Southern Interior Cypress Forest *	N/A	N/A	N/A

In 1993, the CA-GAP data were used to assist the Southern California Association of Governments (SCAG) develop the open space element of their comprehensive regional plan (Crowe 1996). The distribution of vulnerable plant community types were compared with the pattern of land use zoning in the combined general plans of the jurisdictions in the 6 county area. (The only significant land areas not covered by the SCAG plan are Santa Barbara and San Diego Counties). This information was used to highlight plant communities that were not only vulnerable because of land management status but also because of permitted land uses. Here we update that information using the final version of the CA-GAP land-cover map and list of vulnerable types. Table SW-3 shows the types considered vulnerable from the analysis summarized above and the proportion of each that is zoned for development, agriculture, open space/unknown. Public lands such as National Forests are often zoned in the last category by counties, although the actual land uses are determined by planning conducted by the public land management agency. Worth noting in the table are the relatively large proportions of several types zoned for development (coastal scrub types, Big Sagebrush Scrub, Southern Mixed Chaparral, Non-Native Grassland, and Valley Oak Woodland, California Walnut Woodland, and Coast Live Oak Forest). These types, particularly the coastal scrub and the walnut woodlands which have already suffered serious losses, become of more immediate conservation concern because the pressure for conversion is already authorized. Southern Interior Cypress Forest was only mapped in San Diego County and therefore outside the SCAG jurisdiction. Figure SW-4 shows the pattern of vulnerable communities in relation to zoning.