Red Hills Vervain
Red Hills Vervain
|Listed||September 14, 1998|
|Description||Erect perennial herb; has bright green leaves and white-blue to purple blossoms.|
|Habitat||Intermittent and perennial streams within serpentine areas of the Red Hills of Tuolumne County.|
|Threats||Urbanization, recreational placer gold mining, off-highway vehicle use, dumping, and heavy grazing and trampling.|
Red Hills, or California, vervain, Verbena californica, is an erect, perennial herb belonging to the ver-vain family (Verbenaceae). Red Hills vervain grows to 23 in (58 cm) in height and has opposite, bright green, stalkless (sessile) leaves. White-blue to purple blossoms appear in May through September.
Red Hills vervain occurs in nine populations between 850 and 1,150 ft (259 and 350 m) in elevation. The populations are restricted to intermittent and perennial streams within serpentine areas of the Red Hills of Tuolumne County. The entire range of the species is about 10 mi (16 km). Within this narrow range, the total area occupied by the populations is estimated to be 90 acres (36 hectares).
Eight of the nine populations of Red Hills ver-vain occur in drainages that feed into Don Pedro Reservoir; five of these eight are on Six Bit Gulch and its tributaries. The ninth population is on Andrew Creek that feeds into Tullock Reservoir. Four of the nine populations are wholly on Bureau of Land Management (BLM) lands, and two are partially on BLM lands, although these six sites contain only 15% of Red Hills vervain plants. The remaining 85% are on private lands. When last surveyed, two populations were estimated to contain several thousand plants each, four populations were estimated to contain 200-500 plants each, and the remaining three populations were estimated to contain fewer than 100 plants each. The two largest populations, at Andrew Creek and Big Creek, occur entirely or primarily on private lands.
Red Hills vervain is threatened by urbanization, recreational placer gold mining, off-highway vehicle (OHV) use, dumping, and heavy grazing and trampling. Due to the few populations and low numbers, it is also vulnerable to extirpation from random events.
Both of the largest populations of Red Hills ver-vain are on private land that currently is being developed, or could be developed soon. When last surveyed, each of these populations was estimated to contain several thousand plants; the next largest population was estimated to contain fewer than 500 plants. In August 1997, the Tuolumne County Board of Supervisors rescinded the 1994 Environmental Impact Report for a planned subdivision at one of these populations on Andrew Creek. Because of this action, a 1989 vested map dividing the land into 23 parcels is in effect. Grading and road building are currently occurring in Red Hills vervain habitat on the site. This population was estimated to contain at least 35-40% of all Red Hills vervain plants. In addition, it is the only population of Red Hills vervain known from the Andrew Creek drainage and the most westerly population of the species. The second of the two largest populations of Red Hills vervain is on Big Creek. The parcel recently was sold, and the owners are planning to build a house on a knoll about 300 ft (91 m) from the creek where Red Hills vervain grows. The parcel is currently zoned so that it could be divided into 37-acre (15-hectare) parcels. The parcel could be further divided if the general plan was amended; amending can take place three times a year in Tuolumne County. In addition, the busy, nearby intersection of Old Don Pedro Road and La Grange Road may be developed, if the general plan is amended. Other areas of rapid development in the vicinity of Red Hills vervain in Tuolumne County include the intersection of Highways 108 and 120 and the area around Chinese Camp.
Recreational placer gold mining has not been allowed since 1993 in Andrew and Big creeks, but it is still allowed in Poor Man's and Six Bit Gulches. Three populations of Red Hills vervain on BLM land in Six Bit Gulch and one on BLM land in an unnamed drainage between Six Bit Gulch and Big Creek are threatened by recreational placer gold mining. Impacts from casual mining continue to occur despite designation of the entire Red Hills as an Area of Critical Environmental Concern by BLM. Red Hills vervain was only found on areas of the stream in the Six Bit Gulch area where mining activities had not changed land contours and habitat. Another impact from recreational mining is trampling by humans, which negatively affects Red Hills vervain and its habitat.
Field observations suggest that Red Hills vervain can tolerate only light grazing before it disappears from occupied habitat. Even if grazing itself does not threaten Red Hills vervain, trampling associated with grazing negatively impacts the plants and their habitat. One of the two largest populations of Red Hills vervain is subject to trampling and heavy grazing. When last surveyed, this population contained several thousand plants on about 13% of the total acreage occupied by Red Hills vervain, and was estimated to contain approximately 40-50% of all Red Hills vervain plants. Recently, a cattle feeder was installed 10 ft (3 m) from the creek where Red Hills vervain grows at this site, which may increase trampling effects. Trampling has also been identified as a threat at two other populations of Red Hills ver-vain. At one of these sites, the trampling was due to trespass grazing.
Although the public lands in the Red Hills are closed to OHV use, a public loop road was constructed through the area in 1995, and OHV use continues to threaten populations of Red Hills vervain. The BLM continues to issue small numbers of citations for shooting and OHV use in the Red Hills. Trash dumping has also damaged one population of Red Hills vervain on BLM lands in Six Bit Gulch.
Conservation and Recovery
Red Hills vervain occurs in nine locations. Four of the locations are wholly on BLM lands, and two are partially on BLM lands. Owing to the U.S. Fish and Wildlife Service's extensive efforts of public outreach prior to, during, and after the public hearing to list Red Hills vervain, additional public recognition and awareness would not result from the designation of critical habitat. Additionally, as a part of the outreach prior to the California Fish and Game Commission listing Red Hills vervain as threatened, the California Department of Fish and Game notified private landowners who had populations of Red Hills vervain in 1992. Furthermore, the California Fish and Game Commission held a public hearing to take testimony regarding the proposed designation. As a consequence of the state hearing, the California Department of Fish and Game was directed to conduct additional public outreach with landowners within Tuolumne County. The Tuolumne County Planning Department has detailed maps showing the southwest trending stream channels and the distribution of Red Hills vervain. Despite the public education and awareness program for Red Hills vervain ongoing since 1992, destruction of parts of one population occurred in 1997.
Although six of nine known locations are entirely or partially on BLM lands, BLM lands contain only 15% of Red Hills vervain plants. On federal lands, no modification of occupied habitat is likely to occur without consultation under Section 7 of the Act because the presence of Red Hills vervain, and its specific locations are well-known to the managers of these BLM lands. BLM installed, but has not maintained, fencing to exclude cattle from riparian areas in the Andrews Creek drainage that support Red Hills vervain. Eighty-five percent of Red Hills vervain plants are on private lands. Despite repeated searches for additional locations of Red Hills vervain, no other sites containing Red Hills vervain have been identified, and no historic locations are known.
On private lands, federal protection for Red Hills vervain may occur through the Clean Water Act because the species is found in a small series of southwest trending intermittent and perennial serpentinic stream channels within three small watersheds.
U. S. Fish and Wildlife Service
Regional Office, Division of Endangered Species
Eastside Federal Complex
911 N. E. 11th Ave.
Portland, Oregon 97232
U. S. Fish and Wildlife Service. 14 September 1998. "Determination of Threatened Status for Four Plants From the Foothills of the Sierra Nevada Mountains in California." Federal Register 63 (177): 49022-49035.
"Red Hills Vervain." Beacham's Guide to the Endangered Species of North America. . Encyclopedia.com. (April 19, 2019). https://www.encyclopedia.com/environment/science-magazines/red-hills-vervain
"Red Hills Vervain." Beacham's Guide to the Endangered Species of North America. . Retrieved April 19, 2019 from Encyclopedia.com: https://www.encyclopedia.com/environment/science-magazines/red-hills-vervain