Malibu Municipal Code § 3.5 Appendix A—Analysis of Sensitive Terrestrial Habitats by Location

Described below are those marine and terrestrial resources which were identified in the Malibu LCP Land Use Plan to meet the criteria and legal definitions of an environmentally sensitive area, as well as those areas adjoining sensitive habitat which are functionally related to, or act as a buffer to, the sensitive habitat area (Malibu Local Coastal Plan Research and Analysis and Appendices, October, 1992 by the Los Angeles County Department of Regional Planning Coastal Studies Section).

The following describes the environmentally sensitive terrestrial habitats in the Malibu Coastal Zone.

Arroyo Sequit supports some of the most extensive riparian and oak woodland and associated stream habitat (pools and waterfalls) in the MCZ. Dense thickets are located along the East Fork. Above the East Fork, the watershed is undisturbed with the exception of one small stretch of the canyon bottom which contains residential development and camps. The lower half of the canyon is within Leo Carrillo State Park and is undisturbed with the exception of campground facilities located on the canyon floor. Arroyo Sequit may continue to support steel head.

Located within Leo Carrillo State Park, this stream supports dense riparian willow thickets and some scattered trees.

Coast live oak woodland and grassland are located in the uppermost portion of the canyon. The middle section supports diverse and dense riparian woodlands. The lower canyon still retains native trees, although the understory vegetation has been removed due to grading associated with a private recreational facility. Adjacent to the Pacific Coast Highway and extending southward across the highway to the canyon mouth is a less disturbed and more varied riparian woodland. Directly above the beach, at the mouth of San Nicholas Canyon are coastal bluffs which support stands of giant coreopsis and other sensitive coastal bluff plant species. There are also significant marine resources present at this beach.

There is a diverse riparian woodland dominated by western sycamores and coast live oaks at the canyon bottom. Due to residential development in the vicinity of Decker School Road, the woodland has been altered significantly. The riparian woodland, which extends south of Pacific Coast Highway, contains numerous exotic trees, but is dominated by native western sycamores. Significant marine resources are found at this beach.

The Lechuza Canyon watershed is relatively undeveloped from the canyon bottom eastward. There are isolated homes in the western portion. Riparian woodland habitat and associated wildlife exist in the canyon while slopes on the east side support dense stands of coast live oak. A narrow, yet dense stand of riparian woodland extends south of the Pacific Coast Highway to near the beach.

The Clyde Canyon drainage can be traced to Charmlee Meadows. The canyon bottom is intact riparian habit with oaks, sycamores, ferns and other species typical of the habitat type. A rich diversity of wildlife has been observed in the canyon, including bobcat, mountain lion, deer, grey fox, coyote, ring-tail cat, bats, three species of owls, raptors including the golden eagle and kestrel, and Carolella busckana, a C2 candidate species for listing as a federally endangered species.

The floor of this canyon contains dense coast live oak and western sycamore dominated woodland. There is residential development and associated grading on the ridge on the western side of the canyon, while the eastern side of the canyon is undeveloped. South of the Pacific Coast Highway, at the canyon mouth there are native riparian trees interspersed with planted ornamentals.

The upper section of this corridor contains coast live oaks and western sycamores and is considered sensitive. The lower portion of the canyon however, is not considered sensitive as it is disturbed and dominated by non-native plants such as castor-bean, palms and eucalyptus.

This canyon is one of the larger canyons in the MCZ. The upper half of the canyon contains scattered homes, ranches and recreational facilities, while the lower half remains relatively undisturbed. The canyon mouth is largely developed and suburbanized. The Trancas Canyon Watershed is drained by Trancas Creek, the major drainage course into the Trancas Lagoon. The estuary area occupies nine acres. The estuary is a disturbed environmental area which is targeted for restoration by the Santa Monica Bay Restoration Project with the objective of both enhancing the beauty of the area and creating a migration stopover for water fowl.

Additional resident reports about the Canyon resources provide a typical case study of the need for further research in the Malibu region. These reports include the following:

Zuma Canyon is one of the most remote and least disturbed canyons in the Santa Monica Mountains. Coastal sage scrub and chaparral are scattered over the dry slopes, while the canyon bottom contains a diverse riparian woodland and freshwater pools. The pools scattered along the canyon's perennial stream support a distinctive freshwater fauna including western pond turtles and native fishes. Secretive species such as golden eagle (Aquila chrysaetos), bobcat (Fells lynx), and mountain lion (Fells concolor) continue to be sighted in Zuma Canyon. Historically, Zuma Canyon also provided nesting habitat for the peregrine falcon. The Zuma Canyon watershed does not have a significant amount of development. Existing development is confined to the upper and lower limits of this watershed. The upper watershed is developed with a small sewage treatment plant and some residential development. The southern end of the watershed is developed with residential uses. There is one other small developed area within the watershed while the remainder of the watershed is disturbed only by fire breaks and dirt roads. In the southern portion of the watershed the stream and associated riparian woodland have been retained in the residential area and constitutes a disturbed, yet significant streamside habitat. The mouth of Zuma Canyon contains a freshwater estuary and marsh, which is degraded, but has been funded for restoration by the Santa Monica Bay Restoration Project, the National Park Service and Los Angeles County.

This canyon is an upper tributary of Zuma Canyon. While it supports riparian woodlands and dense oak woodlands it has been significantly altered by grading for future and existing development.

This rocky headland supports diverse coastal and upland habitats. The small canyons and ravines dissecting Point Dume support a mixture of exotic and native vegetation dominated by willows, coyote brush, sagebrush and several stands of giant coreopsis. Native vegetation has been replaced in many places by urban development. The upland terrace above the ravines and canyons is almost completely built out with residential development and associated roads, while much of the canyon and ravine habitats have been disturbed by the runoff from these areas. Residents report several pockets of relatively undisturbed riparian corridors and habitat within the Point Dume watershed.

Dense native walnut woodland, willows and scattered elderberry shrubs (Sambucus sp.) are located in this riparian corridor. While it is relatively undisturbed, there is development on the marine terraces lining both sides of the canyon.

The upper and middle sections of Ramirez Canyon are densely wooded with native oaks and scattered western sycamores. The watershed has been disturbed by grading for Kanan Dume Road (which is located on the west side of the canyon) and is also bisected by Pacific Coast Highway. However, the location of the woodland is not affected by the road and supports diverse wildlife. The lower third of the watershed is developed, but the native trees and natural stream are intact throughout the canyon bottom. Development in this area includes a restaurant and mobile homes. Existing data for this canyon may also be somewhat dated. Local residents report personal observation of alder trees in the upper Canyon.

Residential development and associated roads are located within the Ascended Canyon watershed, particularly on the ridge west of the canyon bottom. Latigo Canyon Road runs through portions of the east side of the watershed. A sycamore and oak-dominated woodland is located on the cooler north-facing slopes located west of the stream bottom. The lower and middle sections of the canyon are developed with scattered residential development, much of which is situated in the riparian woodland. While the stream bed and native trees are intact throughout much of the developed lower watershed, they are disturbed in the middle portion where grading and development are more extensive. The mouth of Ascended Canyon extending approximately one-half mile is targeted for restoration from damage due to grading runoff.

The Latigo Canyon watershed contains scattered residential development and Latigo Canyon Road. Compared to other watersheds in the MCZ, Latigo Canyon and its riparian corridor are relatively small. The least disturbed and most heavily wooded portions of the canyon are located below and upstream from the Malibu Vista development. The riparian woodland is fragmented by scattered residential development located just below the sharp bend in Latigo Canyon Road.

Solstice Canyon is a relatively undisturbed watershed with a riparian woodland that supports white alder (Alnus rhombifolia), coast live oak, western sycamore and California bay (Umbellularia californica). A few scattered homes and a narrow road lie at the canyon bottom, but the woodland is intact throughout the canyon. A large native wildlife population is present in this watershed due to both the lack of disturbance and the well-developed vegetation. Unlike many of the other coastal canyons in the area, white alder is present throughout the entire watershed and indicates a perennial supply of water. While the riparian woodland extends down-stream, there is no natural stream habitat south of the highway. The vegetation is however recovering in this area due to a program of exotic vegetation removal and revegetation (Sarah Dixon, Malibu General Plan Task Force, personal communication).

There is some well-developed riparian woodland in Dry Canyon. However it is less diverse than that of the other canyons and is adjacent to the extensive El Nido residential development.

The upper portion of this watershed is heavily wooded with riparian oak woodlands. From the crest to the Ocean, habitats are connected. With the exception of the Malibu Bowl development, a few structures in the lower canyon and scattered dirt roads, the watershed is relatively undisturbed. Corral Canyon is notable for supporting a broad, wooded flood plain at the canyon mouth, north of and immediately adjacent to the Pacific Coast Highway.

Puerco Canyon is a small watershed which is largely undisturbed. The canyon floor is lined with dense willows and associated riparian shrubs while the slopes support coastal sage scrub and chaparral. Due to the undisturbed condition, this canyon supports a large area of high value wildlife habitat.

Malibu Canyon supports oak and riparian woodlands with an unusually large variety of riparian plant species. Black cottonwood (Populus trichocarpa), California bay, leatherleaf ash (Fraxinus velutina var. coriacea), white alder, arroyo willow (Salix lasiolepis), western sycamore, coast live oak, wild grape (Vitis girdiana) and giant chain fern (Woodwardia fimbriata) are all abundant. The majority of the watershed is dominated by a diverse mosaic of chaparral, coastal sage scrub, grassland and native woodlands. Much of the watershed is remote and undisturbed, particularly the northwest and central portions. Malibu Creek, the largest creek in the Malibu area, is biologically distinctive due to the fact that it supports a very diverse flora and fauna which include a number of sensitive species. Malibu Creek also continues to sustain a native steelhead population. These steelhead area remnant population which historically spawned in the upper reaches of the creek. The Rindge Dam has provided a barrier to these reaches since the 1920's, and any spawning which now occurs takes place below the dam. Malibu Canyon also provides habitat for wide-ranging species such as mountain lion and golden eagle. In addition, Malibu Lagoon is located at the mouth of Malibu Creek and is one of only two coastal marshes in Los Angeles County. Malibu Canyon and Malibu Lagoon have been affected by many human impacts including habitat removal, increased siltation, sewage effluent discharge, harassment of wildlife by domestic animals and people, and fragmentation by roads and residences. However, much of the watershed is still undisturbed. Development is concentrated in the extreme upper watershed (Monte Nido, Westlake Village, Agoura Hills, and Calabasas) and the extreme lower watershed (Civic Center area).

The floor of Carbon Canyon is covered with riparian woodland, particularly in the upper sections of the canyon. The lowermost portion of the riparian corridor is disturbed with sparse development located adjacent to Carbon Canyon Road. The west side of the watershed is undeveloped while the east side contains residential development and Rambla Pacifico Road. Rock formations in the upper reaches of the canyon provide roosting and possibly nesting sites for sensitive birds of prey such as golden eagle, peregrine falcon and prairie falcon (Falco mexicana).

Cold Creek Canyon is a relatively undisturbed watershed containing year-round water and supporting native vegetation and wildlife. Undisturbed stands of chaparral, oak woodland, coastal sage scrub, riparian woodland and associated wildlife occur in the canyon. The Cold Creek watershed is the last remaining watershed in the Santa Monica Mountains to support stoneflies (Plecoptera), a group of insects whose aquatic larvae are very sensitive to siltation and urban runoff containing petroleum based compounds. Many other locally uncommon species occur in this area including flowering ash (Fraxinus dipetala), redshank (Adenostoma sparsifolium), Channel Island mountain mahogany (Cercocarpus betuloides var. blanchaea), big leaf maple (Acer macrophyllum), interior live oak (Quercus wizlizenii), Humboldt lily (Lilium humboldtii) and stream orchid (Epipactis gigantea). In addition, several stands of native grassland support Lyon's pentachaeta (Pentachaeta lyonii) within this watershed. Native grassland and Pentachaeta lyonii are both uncommon within the Santa Monica Mountains. The central core of the Cold Creek watershed is generally undisturbed and utilized only for natural resource oriented uses since much of it is in public ownership. However, residential development is present both in the upper and lowermost parts of the drainage basin.

This area is a small, steep hillside which supports an unusual blend of primitive moisture-requiring plant species. These species include mosses, liverworts, hornworts and ferns. These plants form an unusual association with drought-adapted species such as yucca (Yucca whipplei) and other coastal sage scrub species. This unique habitat has developed as a result of rapid runoff in the drainage channel. Hepatic Gulch is mapped as an SEA for these biological resources. However, the mapped location is not co-incident with the actual location of the unusual vegetative association. The area has been affected by upstream drainage from an abandoned Nike Missile site, but now appears to be stable.

Piedra Gorda Canyon is a small, undeveloped watershed. It supports scattered riparian trees and dense riparian thickets. Due to the degree of isolation, wildlife utilization is expected to be extensive.

The middle and upper portions of the canyon are remote and undisturbed, while the lower regions contain substantial development concentrated along Las Flores Road. The riparian woodland and associated stream habitat that extends upstream from the intersection of Gorge Road and Las Flores Canyon Road supports western sycamore, white alder, California bay, coast live oak and associated sensitive understory species.

Tuna and Pena Canyons are adjoining watersheds which are almost completely undisturbed with the exception of concentrated ranch areas and Tuna Canyon Road. The canyons are considered sensitive because they support riparian woodlands, year-round water and the lack of significant development (with the exception of upper Tuna Canyon). The riparian woodlands include dense stands of western sycamore, coast live oak, California bay, white alder (lower half of Tuna Canyon), black cottonwood and giant chain fern. With the exception of off road vehicle tracks in the uppermost portion of the watershed, Pena Canyon is nearly undisturbed. There has been greater human impact in the northwest portion of Tuna Canyon, due to grading and grazing.

Topanga Canyon is the largest coastal watershed in the MCZ and supports extensive riparian vegetation. There is localized residential development throughout the canyon and major holdings of public parklands. Diverse riparian woodlands with coast live oak, western sycamore, and stands of California bay, big leaf maple and cottonwood are located on the canyon bottom and adjacent north-facing slopes. Dense native woodlands are also located in tributaries such as Red Rock, Hondo and Greenleaf. With the exception of Malibu Canyon, the greatest diversity of amphibian and reptile species in the Santa Monica Mountains are reported for this watershed (The Distribution and Present Status of the Herpeto Fauna of the Santa Monica Mountains, Special Publication No. 2, Southwest Herpetological Society, 1986).