What's New
Research & Projects Publications
People
Data
Links

| Home | Contact | UCSB | Bren | ICESS |

 

Appendix CW. The Central Western Region

Contributing Authors: David Stoms, Frank Davis, Mark Borchert, and Josh Graae


Regional Character
Land Stewardship
Plant Community Types


Regional Character

The Central Western California Region (CW), occupying more than 37,000 km², is bounded by the Russian River on the north, the Santa Ynez Mountains of the Transverse Ranges on the south, the Pacific Ocean on the west, and the lower boundary of the foothill woodlands in the San Joaquin Valley on the east. The Temblor Range east of the Carrizo Plain is included in CW as a disjunct part of the Inner South Coast Ranges because it contains oak and juniper woodlands more characteristic of CW than of the surrounding Great Central Valley.

Central


Figure CW-1. Shaded relief image of the Central Western California Region.

The predominant terrain feature of the region is the northwest-southeast trending ridges and valleys of the Coast Ranges. Serpentine rock is frequently found at the surface throughout the region. It is associated with a number of endemic plant species and unusual communities. The coastal side of the mountains is often enveloped in heavy fog, favoring plants that depend on fog drip for summer moisture, such as redwoods and closed-cone pines. These closed-cone pine communities tend also depend on fire to germinate their seeds, so they tend to have very narrow ranges with the right combination of specialized conditions. Elsewhere in the region, we find a repeating pattern with chaparral communities on warmer and drier aspects and evergreen woodlands on cooler, moister ones.

The region has not experienced significantly less pressure from urbanization in comparison with the Southwestern California region. Most development has been restricted to the San Francisco Bay, with smaller communities around Monterey Bay. Much of the valley grasslands, however, have been converted to agriculture in the Salinas, Santa Clara, Santa Maria, and Santa Ynez Valleys. The wine industry has recently boomed, creating vineyards in extensive areas of former oak woodlands.

Land Stewardship

Central Western Region Managed Areas


Figure CW-2. Management status of lands in the Central Western California Region. See text for definitions of management levels.

Figure CW-2 shows the management status of lands in the Central Western California Region. Less than one-quarter of the region is publicly owned, compared to the state as a whole with approximately 50%. The public ownership is widely distributed among U.S. Forest Service (10.9% of the total region), BLM (2.9%), National Park Service (1.1%), Department of Defense (3.9%), state parks (2.0%), California Fish & Game (0.3%), other state land (0.4%), and local jurisdictions (2.9%). Open space districts manage nearly 19,000 ha of land in this region, largely in the mid-peninsula area. The Nature Conservancy (TNC) and other non-governmental organizations own 0.2% of the land area.


Table CW-1. Area and percentage of land surface by management status level of the Central Western California Region.

Status Area (km²) %
1 2,476 6.6
2 1,639 4.4
3 4,782 12.8
4 28,389 76.1
Total 37,286 100.0

The region is very similar to the Southwestern and Northwestern California regions in the proportion of staus 1 and 2 but has less than half as much status 3 land (Table CW-1). Consequently the percentage of status 4 lands (mostly private land) is substantially higher in this region. Some of the management status designations are uncertain. For instance, some of the parklands and open space around the San Francisco Bay are heavily used by recreationists and may even include developed facilities which would change their status to a higher number. Likewise, Hunter-Liggett Military Reservation and Vandenberg Air Force Base were classified as status 3 lands because they contain large areas of important wildlands, but portions of both sites are also heavily used for military operations and training maneuvers.

There are 11 privately owned managed areas or easements, 28 state parks or reserves (not including beaches), 13 Fish & Game ecological reserves and 8 wildlife areas, 5 BLM ACEC's or wilderness areas, 5 USFS Research Natural Areas, 8 USFS wilderness areas, and 4 National Park units. Status 1 and 2 managed areas are dominated by the San Rafael and Ventana wilderness areas, with notable contributions from the Dick Smith Wilderness, Golden Gate NRA, Point Reyes National Seashore, Clear Creek Serpentine ACEC, and Henry W. Coe State Park.

Elevation Bias in CW Region


Figure 5-3. Comparison of the proportion of managed areas with all lands in the Central Western California Region by elevation zones.

The managed areas are distributed unevenly across elevation zones (Figure 5-3). By far the largest zone is below 500 m, containing 2/3 of the land surface but only 1/3 of the area in designated biodiversity management areas. The percentage of private land diminishes rapidly with elevation such that there is virtually none above 1500 m, while the proportion of managed areas far exceeds the proportion of all lands above 1000 m. This elevational pattern reflects the wilderness designations in the higher mountains and the relative lack of protection at low elevations.

Plant Community Types

Vegetation polygons were attributed using VTM data, maps of hardwood forests and woodlands (Pillsbury 1990) and redwoods (Fox 1988), and field surveys. Air photo interpretation techniques were used to confirm, enhance, and in cases where no other data were available, supply polygon attributes. National High Altitude Photography (NHAP) and NASA-JPL color infrared transparencies were viewed stereoscopically to identify vegetation types, their proportional extent in a landscape mosaic, and canopy closure. The NHAP photos are at a scale of 1:58,000 and dated from 1980-1984, while the NASA-JPL photos are at a scale of 1:65,000 and dated late 1980s to early 1990s. Of the 3,595 landscape units mapped, 328 were visited in the field.

We classified 29,282 km² (79%) of the CW region as vegetated other than agricultural or horticultural land cover. In other words, 21% has been converted to urban or agricultural uses or contains open water or bare ground. The vegetation layer was delineated into 3,595 landscape units with an average size of 1,037 ha. Distributional information is provided on 152 dominant plant species, 76 community types, and 15 land use/land cover types.


Table CW-2. Percent area of each CNDDB community type at each management status level in the Central Western California Region.

CNDDB Code CNDDB Community Name (Holland 1986) CNDDB Rank Status 1 % Status 2 % Status 3 % Status 4 % Total Mapped Distribution (km²) Status 1+2 %
21210 Northern Foredunes S2.1 0.0 100.0 0.0 0.0 0.3 100.0
21320 Central Dune Scrub S2.2 16.6 11.0 59.8 12.5 13.6 27.6
31100 Northern Coastal Bluff Scrub S2.2 9.1 90.9 0.0 0.0 39.1 100.0
32100 Northern (Franciscan) Coastal Scrub S4/3.2/2.3 10.2 15.3 4.0 70.5 423.2 25.5
32200 Central (Lucian) Coastal Scrub S3.3 3.3 4.3 25.2 67.2 680.5 7.6
32300 Venturan Coastal Scrub S3.1 12.3 1.7 21.0 65.1 631.3 14.0
32600 Diablan Coastal Scrub S3.3 0.7 0.4 9.7 89.1 780.7 1.1
35210 Big Sagebrush Scrub S4 50.0 0.0 50.0 0.0 5.0 50.0
36220 Valley Saltbush Scrub S2.1 0.0 0.0 11.5 88.5 14.8 0.0
37110 Northern Mixed Chaparral S4 32.5 0.0 23.5 44.0 15.0 32.5
37200 Chamise Chaparral S4 18.1 3.6 24.4 53.9 2,302.2 21.7
37300 Red Shank Chaparral S3.2 15.5 0.0 30.6 54.0 8.4 15.5
37400 Semi-Desert Chaparral S3.2 15.6 8.4 29.1 46.9 494.9 24.0
37510 Mixed Montane Chaparral S4 15.1 21.6 13.0 50.3 15.5 36.7
37520 Montane Manzanita Chaparral S4 30.0 42.1 16.3 11.6 21.6 72.1
37530 Montane Ceanothus Chaparral S4/3.3 46.1 0.0 44.5 9.4 20.9 46.1
37610 Mixed Serpentine Chaparral S2.1 0.5 2.8 29.5 67.2 62.0 3.3
37620 Leather Oak Chaparral S3.2 0.2 18.7 20.1 60.9 94.5 18.9
37810 Buck Brush Chaparral S4 16.5 2.8 35.0 45.7 2,983.9 19.3
37820 Blue Brush Chaparral S4 5.3 9.4 12.5 72.8 68.3 14.7
37830 Ceanothus crassifolius Chaparral S3.2 0.0 0.0 0.0 100.0 1.5 0.0
37840 Ceanothus megacarpus Chaparral S3.2 0.0 0.0 55.9 44.1 4.1 0.0
37900 Scrub Oak Chaparral S3.3 30.7 0.8 42.3 26.2 436.4 31.5
37A00 Interior Live Oak Chaparral S3.3 51.1 1.1 31.8 15.9 428.0 52.2
37B00 Upper Sonoran Manzanita Chaparral S4 45.9 3.9 17.6 32.6 266.5 49.8
37C10 Northern Maritime Chaparral S1.2 18.3 0.0 38.3 43.3 2.9 18.3
37C20 Central Maritime Chaparral S2.2 6.4 7.1 47.7 38.8 218.0 13.5
37E00 Mesic North Slope Chaparral S3.3 31.3 7.2 37.6 23.8 293.0 38.5
37G00 Coastal Sage-Chaparral Scrub S3.2 3.5 3.7 19.7 73.1 152.3 7.2
39000 Upper Sonoran Subshrub Scrub S3.2 2.7 0.4 27.5 69.5 191.7 3.1
41000 Coastal Prairie S2.1 0.8 8.4 2.5 88.4 749.2 9.2
42200 Non-Native Grassland S4 0.4 2.7 5.6 91.3 6,958.3 3.1
52110 Northern Coastal Salt Marsh S3.2 4.4 40.7 5.7 49.2 80.2 45.1
52310 Cismontane Alkali Marsh S1.1 0.0 0.0 0.0 100.0 4.5 0.0
52410 Coastal and Valley Freshwater Marsh S2.1 11.6 3.9 30.7 53.9 5.6 15.5
61130 Red Alder Riparian Forest S2.2 0.0 0.0 0.0 100.0 2.4 0.0
61210 Central Coast Cottonwood-Sycamore Riparian Forest S3.2 7.4 1.5 14.6 76.5 77.6 8.9
61220 Central Coast Live Oak Riparian Forest S3.2 8.4 7.0 5.6 78.9 29.2 15.4
61230 Central Coast Arroyo Willow Riparian Forest S3.2 1.5 0.3 42.3 55.9 42.5 1.8
62100 Sycamore Alluvial Woodland S1.1 6.5 0.0 44.3 49.2 9.0 6.5
63200 Central Coast Riparian Scrub S3.2 0.0 3.4 0.0 96.6 2.1 3.4
63310 Mule Fat Scrub S4 1.5 0.0 0.4 98.2 28.9 1.5
71120 Black Oak Woodland S3.2 9.0 12.3 12.4 66.3 66.4 21.3
71130 Valley Oak Woodland S2.1 0.2 2.3 18.2 79.3 163.2 2.5
71140 Blue Oak Woodland S3.2 1.8 2.6 12.6 83.0 2,143.4 4.4
71160 Coast Live Oak Woodland S4 1.9 2.9 8.6 86.7 954.1 4.8
71170 Alvord Oak Woodland S2.2 1.3 0.0 9.6 89.2 339.7 1.3
71310 Open Foothill Pine Woodland S4 3.1 0.2 19.7 77.0 197.0 3.3
71321 Serpentine Foothill Pine-Chaparral Woodland S3.2 18.1 1.8 25.9 54.2 33.0 19.9
71322 Non-Serpentine Foothill Pine Woodland S4 17.2 0.0 13.2 69.7 5.8 17.2
71410 Foothill Pine-Oak Woodland S4 1.9 4.2 11.2 82.6 2,232.3 6.1
71430 Juniper-Oak Cismontane Woodland S3.2 0.0 0.4 18.6 81.0 157.9 0.4
72200 Mojavean Pinyon and Juniper Woodland S3.2/4 42.1 0.0 57.9 0.0 15.2 42.1
72400 Cismontane Juniper Woodland and Scrub S2.1 0.0 4.5 15.4 80.2 31.2 4.5
81100 Mixed Evergreen Forest S4 15.4 12.7 8.8 63.1 1,625.0 28.1
81200 California Bay Forest S3.2 0.0 5.9 29.1 65.0 9.2 5.9
81310 Coast Live Oak Forest S4 3.4 2.1 9.2 85.3 1,318.5 5.5
81320 Canyon Live Oak Forest S4 69.6 0.0 26.0 4.4 61.7 69.6
81330 Interior Live Oak Forest S4 16.9 14.2 15.6 53.4 43.6 31.1
81340 Black Oak Forest S4 0.0 12.8 1.4 85.8 38.5 12.8
81400 Tan-Oak Forest S4 21.4 1.8 22.4 54.4 31.9 23.2
82320 Upland Redwood Forest S2.3 4.1 21.2 6.6 68.1 799.9 25.3
82420 Upland Douglas-Fir Forest S3.1 46.0 17.9 0.8 35.3 49.7 63.9
83120 Bishop Pine Forest S2.2 31.5 33.4 7.2 27.8 44.5 64.9
83130 Monterey Pine Forest S1.1 5.7 1.8 3.7 88.8 39.2 7.5
83210 Knobcone Pine Forest S4 26.8 19.1 14.0 40.1 18.6 45.9
83220 Northern Interior Cypress Forest S2.2 0.0 18.4 48.4 33.2 7.4 18.4
84110 Coast Range Mixed Coniferous Forest S4 69.8 21.4 0.2 8.6 10.1 91.2
84120 Santa Lucia Fir Forest S2.2 100.0 0.0 0.0 0.0 8.4 100.0
84130 Coast Range Ponderosa Pine Forest S3.2/1.1 10.2 12.2 30.8 46.8 42.5 22.4
84140 Coulter Pine Forest S3.2 37.9 1.5 15.6 45.0 95.0 39.4
84150 Bigcone Spruce-Canyon Oak Forest S3.2 43.4 0.0 56.3 0.3 21.1 43.4
84180 Ultramafic Mixed Coniferous Forest S4 0.0 87.2 0.1 12.7 25.7 87.2
84210 Westside Ponderosa Pine Forest S2.1 100.0 0.0 0.0 0.0 4.3 100.0
85100 Jeffrey Pine Forest S4 100.0 0.0 0.0 0.0 0.7 100.0
85210 Jeffrey Pine-Fir Forest S4 99.5 0.0 0.5 0.0 3.0 99.5

Region Total - Natural Communities




29,282

Region Total - All Lands
6.6 4.4 12.8 76.1 37,274 11.0

Of the 76 natural plant communities, 48 have a mapped distribution greater than 25 km² (Table CW-2). These 48 plant communities are the focus of the vegetation analyses in this report. The 7 most extensive community types mapped are Non-Native Grassland (42200), almost 7,000 km² (24% of native community types); Buck Brush Chaparral (37810), almost 3,000 km² (10%); Chamise Chaparral (37200), 2,302 km² (8%); Foothill Pine-Oak Woodland (71410), 2,232 km² (8%); Blue Oak Woodland (71140), 2,143 km² (7%); Mixed Evergreen Forest (81100), 1,625 km² (6%); and Coast Live Oak Forest (81310), 1,319 km² (5%).

Four categories of distribution are summarized here from Table CW-2 for plant communities mapped over greater area than 25 km².

1. Plant community types mainly on status 4 (primarily private) lands. Eleven types out of 48 have more than 80% of their mapped distribution on status 4 lands. These are predominately lower elevation types such as Diablan Coastal Scrub (32600), Coastal Prairie (41000), Non-native Grassland (42200), Mule Fat Scrub (63310), Blue Oak Woodland (71140), Coast Live Oak Woodland and Forest (71160 and 81310), Alvord Oak Woodland (71170), Foothill Pine-Oak Woodland (71410), Black Oak Forest (81340), and Monterey Pine Forest (83130). Many of these types are subject to the impacts of livestock grazing on the extensive ranch lands throughout the region. Privately owned oak woodlands are rapidly being converted to vineyards in many parts of the region to accommodate the booming wine industry.

2. Scrub, chaparral, and herbaceous types mainly located in unprotected areas. Eight of the scrub, chaparral, and herbaceous types mapped to areas greater than 25 km² are represented by less than 10% in status 1 or 2. Types in this category include both Central (Lucian) and Diablan Coastal Scrub (32200 and 32600), Mixed Serpentine Chaparral (37610), Coastal Sage-Chaparral Scrub (37G00), Upper Sonoran Subshrub Scrub (39000), Coastal Prairie (41000), Non-Native Grassland (42200), and Mule Fat Scrub (63310). Of these, the Mixed Serpentine Chaparral and the Coastal Prairie types are considered to be relatively rare and very threatened by the Natural Heritage Division.

3. Forest and Woodland types located mainly in unprotected areas. Twelve forest and woodland types identified as over 25 km² in area have less than 10% status 1 or 2 representation. This includes all of the oak and foothill pine types mentioned in category 1 above, except for Black Oak Forest. The additional types are Central Coast Cottonwood-Sycamore Riparian Forest (61210), Central Coast Arroyo Willow Riparian Forest (61230), Valley Oak Woodland (71130), Open Foothill Pine Woodland (71310), Juniper-Oak Cismontane Woodland (71430), and Cismontane Juniper Woodland and Scrub (72400). Although Monterey Pine has been planted widely as an ornamental and commercial species, it is considered very rare and threatended in its three natural stands (Holland 1986). The two juniper types are endemic to the Inner Coast Ranges of this region.

4. Community types that appear well protected. Fifteen plant communities of the 48 in the region with areas greater than 25 km² have more than 25% of their extent in status 1 and 2. These 15 types are clumped into montane chaparral (Scrub Oak, Interior Live Oak, Upper Sonoran Manzanita, Mesic North Slope) and coniferous forest communities (Mixed Evergreen, Canyon Live Oak, Interior Live Oak, Upland Redwood, Upland Douglas-Fir, Bishop Pine, Coulter Pine, and Ultramafic Mixed Coniferous Forest), generally at higher elevations, plus 3 coastal types (Northern Coastal Bluff and Northern [Franciscan] Coastal Scrub and Northern Coastal Brackish Marsh). Most of these have relatively limited distributions in the CA-GAP database, typically <100 km². Noteworthy exceptions are Mixed Evergreen Forest (81100) mapped over 1,600 km² and Upland Redwood Forest with 800 km². It should be noted, however, that Mixed Evergreen Forest is a very heterogeneous type, composed of many combinations of dominant species. Stoms et al. (in review) recognized 23 specific types of Mixed Evergreen Forest in this region, with varying levels of protection. Although the type appears to be well-represented in managed areas, we recommend that more homogeneous types be described and a new gap analysis be done before making final conclusions. The entire range (8 km²) of Santa Lucia Fir Forest (84120) is within the Ventana Wilderness.

Several other community types are of conservation concern despite having >10% of their area in managed areas or <25 km² mapped in this region. Central Maritime Chaparral (37C20) is composed of combinations of narrowly distributed manzanita species that occur nowhere else. Only 13.5% of the mapped area is managed primarily for biodiversity. Like most other riparian types, the Central Coast Live Oak Riparian Forest is considered at-risk, even though 15.4% of its range is already protected. Maritime Coast Range Ponderosa Pine Forest (84132) is a narrowly restricted and highly threatened type. It is restricted to sterile marine sand deposits of the Santa Margarita Formation in Santa Cruz County (Scotts Valley-Ben Lomond and Bonny Doon areas) and is fire-dependent (Holland 1986). This subtype was not specifically mapped by CA-GAP but was included in the widespread Coast Range Ponderosa Pine Forest (84130) which was not found to be highly vulnerable overall in this analysis. Sycamore Alluvial Woodland (62100) and Cismontane Alkali Marsh (52310) are rare, very threatened types, and yet uner-represented in this region.


CA-GAP Home | Overview | Report | Download GIS | CD-ROM | Site Index | National GAP

Top of Page

Send your comments to: stoms@geog.ucsb.edu

UCSB Biogeography Lab Home

Email stoms@bren.ucsb.edu