Appendix A - Special Designation Overlays Research Natural Areas

Appendix A - Special Designation Overlays

Research Natural Areas

Established

The Agua Tibia Research Natural Area (RNA) was established for the study of bigcone Douglas-fir. Located within the Agua Tibia Wilderness, the site is relatively undisturbed and contains typical bigcone Douglas-fir habitat characteristics. The target species occurs on northern slopes and canyon bottoms at lower elevations and on various aspects at higher elevations. It has a sparse herb layer and occurs on very steep slopes. The trees are somewhat fire resistant, but would be eliminated by frequent fires. The surrounding vegetation that would provide a defensible space zone is predominantly broadleaf chaparral. Access to the RNA is either through Cutca Valley or through the Mission Indian Reservation, both involving some strenuous hiking.

The King Creek Research Natural Area (RNA) located on the Descanso Ranger District adjacent to Cuyamaca Rancho State Park contains a small, rare population of Cuyamaca cypress, a relic of the ancient genus Cupressus, which was once widespread across North America. Cuyamaca cypress exists in six distinct stands on the national forest and also on state park land on the slopes of Cuyamaca Peak. All of the King Creek stands burned in a fire in 1950. Access to the RNA by trail is good, and a powerline road forms the northern boundary. Cuyamaca cypress is considered a federal 'Species of Concern' (former candidate for listing) and has also been designated a Region 5 sensitive plant species. Most of the Cuyamaca cypress in both the RNA and in Cuyamaca Rancho State Park burned in the 2003 Cedar Fire, but regeneration is expected to be adequate to repopulate the stands because trees were old enough to have substantial cone banks at the time of the fire.

The Organ Valley Research Natural Area (RNA) located on Black Mountain is dedicated to the study of Englemann oak (Quercus engelmannii). Englemann oak woodlands are distributed within a very limited area of cismontane southern California and northern Baja California, Mexico. Many of the original groves have been destroyed by overgrazing and/or development. The stands located within the RNA also suffer to some degree from the deteriorating factors mentioned above; however, Organ Valley has not been grazed for some time and the site is relatively undisturbed. The Englemann oaks are healthy and vigorous. They vary in size, representing several age classes. Two Region 5 sensitive plants also occur in the oak habitat; Orcutt's brodiaea (Brodiaea orcuttii) and velvety false-lupine (Thermopsis macrophylla var. semota).

Proposed

The Guatay Mountain Research Natural Area (GMRNA) is located in San Diego County, California, on the Descanso Ranger District of the Cleveland National Forest. It is approximately 36 miles (58 km) inland from the Pacific Ocean and 18 miles (29 km) north of the Mexican border. The 1,337 acre RNA, 435 acres (176 ha) of which is designated as a botanical special interest area lies entirely on lands managed by the Cleveland National Forest, which is the sole administrator of the RNA. Although a portion of the land area within the RNA is newly acquired and consequently outside the Forest Service Congressional boundary, the land has approved purchase unit status and therefore has National Forest System lands status.

The land bordering the GMRNA to the north and west is privately owned with rural residential development, including the town of Guatay (population 782 in 2000). To the east and southeast, GMRNA is bordered National Forest System lands. The southern border of the RNA is a privately owned cattle ranch.

GMRNA is located near the former sites of two Native American villages. Residents of these villages regarded Guatay Mountain as sacred. Formerly included within grazing allotments, grazing was excluded from the area in 1998. Day hikers occasionally visit the peak, but otherwise recreation use is infrequent.

Guatay Mountain is important as representative of the Tecate cypress (Cupressus forbesii) forest and mafic southern mixed chaparral vegetation types. Tecate cypress is listed as rare and endangered by the California Native Plant Society (CNPS). The Tecate cypress stand within GMRNA is the only known occurrence of this species and this vegetation type on Forest Service land. Guatay Mountain is also distinctive in its geology and soils. Developed on mafic rock types (loosely termed 'gabbro') that underlay most of area, the soils of GMRNA support distinctive vegetation and species not found on other soil types, including Calochortus dunnii, listed as rare by the state of California (California Department of Fish and Game 2003b) and rare and endangered by CNPS (California Native Plant Society 2003).

The portions of the RNA not included in the Tecate Cypress Botanical Special Interest Area are currently designated General Forest Roaded (mixed emphasis) in the Cleveland National Forest Land and Resource Management Plan (US Forest Service, Cleveland National Forest 1986).

Guatay Mountain Research Natural Area was formally nominated by the Cleveland National Forest in May, 1995, after a site visit by a four-member team of ecologists and biologists from Pacific Southwest (PSW) Research Station and Cleveland National Forest (Phillips 1995). Designation of the RNA was included as a guideline in the Tecate cypress Species Management Guide and Fire Management Guide, approved by Cleveland National Forest in October, 1991 (Winter 1992).

The Viejas Mountain Research Natural Area (VMRNA) is located in San Diego County, California on the Descanso Ranger District of the Cleveland National Forest. It is approximately 30 miles (48 km) east of the Pacific Ocean and 20 miles (32 km) north of the Mexican border.

The 3,182 acre RNA lies entirely on lands managed by the Cleveland National Forest, which is the sole administrator of the RNA.

Ownership of the land bordering the VMRNA is a mix of private, communal, and public. Lands to the north of the RNA are within the El Capitan Indian Reservation, and lands to the east are within the Viejas Indian Reservation. To the south and west, private property is interspersed with lands of the Cleveland National Forest.

Viejas Mountain is representative of the chamise chaparral vegetation type, and is recognized as having high biodiversity and research potential. The chamise chaparral within the RNA is representative of the gabbroic variant of chamise chaparral common in the Cleveland National Forest, and consequently captures important variation of this widespread type. Viejas Mountain RNA also provides habitat for San Diego thornmint (Acanthomintha ilicifolia), a species federally-listed as threatened, California State-listed as endangered, and recognized by the California Native Plant Society (CNPS) as rare and seriously endangered, as well as six additional plant species recognized as sensitive by the Regional Forester and/or CNPS. Twelve animal species of special concern to the State of California are known or expected to occur within the RNA. The peak of the mountain has special importance to the Kumeyaay Nation (Shipek 1985).

The Viejas Mountain area was formally nominated as a Research Natural Area by the Cleveland National Forest in May, 1995, after a site visit by a four-member team composed of ecologists and biologists from the Pacific Southwest Research Station (PSW) and the Cleveland National Forest (Phillips 1995). The Viejas Mountain area was previously considered as a botanical special interest area, but RNA designation was seen as more appropriate in view of the high research potential of the site.

The San Diego River Research Natural Area (SDRRNA) is located in San Diego County, California on the Palomar Ranger District of the Cleveland National Forest. It is approximately 30 miles (48 km) east of the Pacific Ocean and 21 miles (33 km) north of the Mexican border. The RNA lies entirely on lands managed by the Cleveland National Forest, which is the sole administrator of the RNA.

Ownership of the land bordering the SDRRNA is a mix of private individuals, communal, and public institutions. A coalition of tribes manages the Capitan Grande Indian Reservation on the south of the RNA. Helix Water District owns a two-mile (3.2 km) stretch of the San Diego River streambed and the adjacent ¼ mile (0.4 km) wide floodplain. The San Diego Country Estates development and the Barona Mesa rural residences border the southwest of the RNA. Land on the northwest is private land regulated by San Diego County under the zoning code of Agricultural Zone 20.

Prior to 1930, the San Diego River bottom area was probably used as a temporary village settlement for the Barona Indians. Currently, recreation is the major use of the area; activities are concentrated in the southern part of the RNA. Cedar Creek Falls is a popular destination for hikers, cyclists, and horseback riders. SDRRNA has been used for scientific research studying the unusually high biodiversity and fire ecology. Scientists conducting studies in the RNA are from Forest Service, non-profit organizations (California Native Plant Society [CNPS] and the Nature Conservancy), and academics (University of California at San Diego, San Diego State University, and Pomona College).

San Diego River area was recognized as unique and important for its inland coastal sage scrub community and riparian habitat. California sagebrush (Artemisia californica) is the dominant shrub, which is one of the primary plant species associated with the California gnatcatcher (Polioptila californica), a federally listed threatened species. Most of the SDRRNA is included in a proposed critical habitat for the California gnatcatcher (USDI Fish and Wildlife Service [USFWS] 2000a,b). As of June 23, 2003, the critical habitat designation has not been finalized. The riparian zone in SDRRNA and Helix Water District property was once considered by the USDI Fish and Wildlife Service (2001) to be designated as critical habitat for arroyo southwestern toad (Bufo microscaphus californicus), a federally listed endangered species, but the designation was vacated in fall, 2002.

San Diego River area was formally nominated as an RNA by the Cleveland National Forest in May, 1995, after the site was visited by a seven-member team composed of ecologists and biologists from the Pacific Southwest (PSW) Research Station and the Cleveland National Forest. Nomination of the SDRRNA is part of a Habitat Conservation Agreement developed with the USFWS to further the protection of coastal sage scrub.

The entire area of the proposed RNA was burned in the 2003 Cedar Fire. Most of the target vegetation elements should recover naturally. Some of the coastal sage scrub has now burned three times since the early 1990s, making the proposed RNA a natural laboratory for the study of frequent fire effects on this vegetation type.

Next Section: Appendix A - Special Interest Areas