Golden Paintbrush

Castilleja levisecta

Description

Golden paintbrush, Castilleja levisecta, is a perennial herb of the snapdragon family (Scrophulariaceae). Golden paintbrush typically has one to 15 erect to spreading unbranched stems, reaching a height of 12 in (30.5 cm), and is covered with soft, sticky hairs. The lower leaves are entire and narrowly pointed; the upper leaves are broader, usually with one to three pairs of short lateral lobes on the distal end. The flowers, which appear from April to June, are mostly hidden by the overlapping bracts. Each has a deeply cleft calyx 0.6-0.7 in (1.5-1.8 cm) long and a corolla 0.8-0.9 in (2-2.3 cm) long, with a slender galea (concave upper lip) three to four times the length of the unpouched lower lip. It is distinguished from the other Castilleja species within its range by brilliant golden to yellow floral bracts, although the plant is less conspicuous when not flowering. The species may be semiparasitic like other members of the genus Castilleja, possibly requiring a host plant for seedling development in its native habitat. Greenhouse experiments indicate, however, that it does not require a host to survive and flower.

Several characteristics of this taxon make it difficult to determine accurate counts of it when surveying in the field. This plant tends to grow in clumps, one genetic individual may consist of one to 15 stems, and the number of stems per plant varies from site to site. To add to the difficulty in obtaining reliable population data, researchers have used a variety of census methods over the years. Population estimates have therefore ranged widely from year to year, and they will probably continue to do so until a consistent counting approach can be defined and upheld. Experimentally designed sampling surveys have been conducted where individual plants were tagged and counted; perhaps this will resolve some of the confusion over census methodology.

Habitat

Golden paintbrush occurs in open grasslands around the periphery of the Puget Trough, at elevations below 328 ft (100 m). Most populations occur on glacially derived soils, either gravelly glacial outwash or clayey glacio-lacustrine sediments. Associated species include Festuca idahoensis, F. rubra, Camassia quamash, Holcus lanatus, Achillea millefolium, Pteridium aquilinum, Vicia spp., and Bromus spp. Frequent and low intensity fires can be important in maintaining habitat for plant species such as golden paintbrush, as research has shown that periodic fires in the Puget Trough have been historically instrumental in maintaining native grassland habitat by limiting successional encroachment of trees and shrubs. Western Oregon, Washington, and southern Vancouver Island have a maritime climate that is characterized by wet, mild winters and cool, relatively dry summers. Annual precipitation averages 31-53 in (78.8-134.6 cm) in the Puget-Willamette Trough.

Distribution

Golden paintbrush has been reported from more than 30 historical sites in the Puget-Willamette Trough of Oregon, Washington, and British Columbia, Canada. A 1984 status assessment of this species found the plant extirpated from more than 20 historic sites, many of them eliminated due to conversion of habitat through agricultural, residential, and commercial development. The area around the type locality at Mill Plain, Washington, was converted to pasture and orchards some time after the plant was first collected there in 1880. Housing developments currently occupy the site. Golden paint-brush historically occurred in the grasslands and prairie of the Willamette Valley, but the species has been extirpated by habitat destruction from all of its Oregon sites.

C. levisecta is now known from ten extant populations in open grasslands distributed throughout three counties in Washington and two islands in British Columbia. The eight Washington populations are located as follows: one population south of Olympia in Thurston County, five populations on Whidbey Island in Island County, one population on San Juan Island in San Juan County, and one population on Lopez Island in Island County. Two populations exist on islands off the southern coast of Vancouver Island, British Columbia. This not very robust number of populations was anticipated to dwindle in the 1990s. The Lopez Island population consisted of four plants in May 1996, but this occurrence will likely not survive since groups of less than five individuals are not considered viable. At least one historic population in Canada has been extirpated in the 1990s. Three individuals were observed in 1991 at Beacon Hill in Victoria, but subsequent annual surveys through 1996 have failed to find any plants.

The southernmost population of golden paint-brush occurs at the Rocky Prairie site south of Olympia, in Thurston County. The entity, owned by the Washington Department of Natural Resources, is designated as a Natural Area Preserve that is managed primarily for protection of golden paint-brush and white-topped aster (Aster curtus ) and conservation of the remnant native grasslands of Idaho fescue (Festuca idahoensis ). The last complete census in 1983 counted 15,000 plants sporadically distributed throughout 37 acres (15 hectares). A 1985 fire reduced the southernmost patch of golden paintbrush, and in 1991 the total population was estimated to be about 7,000 plants.

Five populations are located on the north half of Whidbey Island in Puget Sound, and they will be discussed in order from largest to smallest. The largest of the Whidbey Island populations occurs near Forbes Point at Crescent Harbor, measures about 66 by 197 ft (20 by 60 m), and is owned by the Department of Defense (Whidbey Island Naval Air Station). A census conducted for golden paint-brush in 1985 counted more than 10,000 flowering stems at the site, although the number of individual plants was not provided. The population was monitored in 1990, when it was estimated to be in the thousands, and again in 1991, when a reduction in density of about 25% was observed. A census completed in May 1995 numbered 1,346 plants with 5,243 stems, approximately 50% of the 1985 total.

The West Beach population is on a privately owned site less than 1 acre (0.4 hectares) in size that is bisected by a county road. The east side of the road supported 10-20 plants in 1992, whereas the entire West Beach population was estimated at approximately 200 plants in 1984. A 1993 census of the site found 496 plants, while the 1995 census counted 550 plants west of the road. This apparent increase in this population may represent a real increase in population size, a natural year to year fluctuation in plant individuals, differences in the way individual plants were determined between 1993 and 1995, or that a more complete count was conducted in 1995.

The Ebey's landing population, occurring in a 33-66 ft by 328 ft (10-20 m by 100 m) area on private land, was estimated to contain 300-400 plants in 1984 and more than 4,000 individuals in 1993. These divergent population estimates are probably caused by differences in estimation techniques, such as counting individuals rather than flowering stems and extrapolating numbers based on sampled population density.

The Bocker property, owned by Seattle Pacific University, is used for environmental education courses, although no covenants or other restrictions on this land exist that could prevent future development. This population consists of a 197 by 492 ft (60 by 150 m) colony directly on the property, a second colony adjacent to the property, and a 15 by 30 ft (4.5 by 9 m) colony located near the admiral's former residence. The population at this site in 1996 had plummeted to 306 plants from an estimated 1,200 plants in the mid-1980s.

The Fort Casey State Park population, numbering between 500 to 1,000 plants in the early 1980s, declined to 120 plants in 1993; two years later this occurrence on state-owned land harbored about 230 individuals in a 0.1 acre (0.04 hectare) area. The Ebey's landing, Fort Casey, and Bocker property populations are located within the administrative boundary of the Ebey's Landing National Historic Reserve (ELNHR).

The population on San Juan Island in San Juan County is located on a privately owned parcel near the Mar Vista resort at False Bay. The site supports a population of 128 plants on less than 1 acre (0.4 hectares).

The final U.S. population of this taxon is at Davis Point on Lopez Island in Island County. This occurrence on private land consisted of a single plant when first discovered in 1994; a census conducted in May 1996 found four plants. The viability of the Davis Point population is highly questionable based on what little is known about its past size, as well as the present circumstances it faces. Photographic evidence secured at an unknown time after 1980 but prior to 1994, indicated this population was historically much larger, with an estimated 100 golden paintbrush plants. However, the area is now dominated by non-native grasses that likely have out-competed golden paintbrush at the site.

Although this plant was historically recorded from nine locations on southeastern Vancouver Island in British Columbia, only two extant populations are definitely known to survive on small islands near Victoria. One population, located on Alpha Islet, consists of 1,000 plants in an area of 33 by 33 ft (10 by 10 m). A second population of about 2,560 plants is located on the Trial Islands in an area of about 1.2 acres (0.48 hectares) and is currently managed by the Ministry of Parks as an ecological reserve.

Threats

Historic loss of prairie and grassland habitat in the Puget Trough has drastically reduced the number of golden paintbrush populations, and habitat loss continues to be the primary threat to remaining occurrences of this taxon. Golden paintbrush is threatened by competition with encroaching native and alien woody plants, habitat modification through succession of grassland to shrub and forest lands in the absence of fire, and reduced vigor and reproductive potential due to grazing by herbivores. Direct humanly caused threats include conversion of habitat for residential and commercial development, conversion of land to agriculture, possible damage associated with road maintenance, and trampling or collecting by the public during recreational use of sites.

Interspecific competition, specifically tree and shrub succession, has become a serious threat to the continued existence of golden paintbrush. Grassland habitat has been maintained historically by periodic fires that prevented encroachment of woody plant species. The systematic suppression of fire in the century and a half since 1850 has played a critical role in the reduction of grassland habitat in the Puget Trough, and it has also greatly reduced the numbers and sizes of C. levisecta populations. Fire suppression in recent years especially has led to invasion of grasslands by native species such as Douglas fir, wild rose, and barberry, which form closed canopies under which golden paintbrush cannot survive. Cytisus scoparius and Hieracium pilosella are alien plants that have also increasingly encroached on grasslands due to the reduction in scope and number of natural fires. These five species are invasive; compete with golden paintbrush for root space, light, and nutrients; and possess the capacity to dominate many of the habitats they usurp.

Golden paintbrush appears to be unable to compete successfully against species that tend toward monoculture; the invasion of woody species and consequent loss of habitat threatens the Rocky Prairie Natural Area Preserve, Ebey's landing, Fort Casey State Park, Bocker property, West Beach, and Forbes Point populations. Encroachment of wild rose and blackberry, if left unchecked, will eliminate the population at the West Beach site. The Bocker property population has declined by 75% since 1984, mostly due to this influx of invasive plants. Vetch and clover have also intruded into golden paintbrush habitat at Forbes Point. Davis Point is another location that has apparently suffered from plant encroachment. Golden paintbrush is found here on a small patch within an unmanaged and overgrown 30 acre (1.2 hectares) lot; pasture grasses and wild rose are abundant and threaten to eliminate this taxon, which has declined from about 100 plants prior to 1994 to four individuals in 1996.

Fire prevention is a twofold threat to this species because freely burning fires keep grassland habitats suitable for golden paintbrush and the physical act of dousing fires can harm or destroy individual plants, an example of which took place in Thurston County in August 1996. A spark cast off from a train that runs adjacent to Rocky Prairie ignited a fire that burned grasses and shrubs for more than than 10 mi (16 km) of the railroad right-of-way. The fence surrounding Rocky Prairie Natural Area Preserve was cut at two locations to allow access to fire-suppression vehicles. These trucks ran directly over a portion of the golden paintbrush population at the site, breaking and compacting individual plants. Damage of this kind to plants and habitat is not uncommon during suppression of wildfires. A large, high intensity fire at any of the remaining C. levi-secta sites would obviously jeopardize that entire population, although the U.S. Fish and Wildlife Service (FWS) is not aware of permanent extirpations of this species due to fire.

The privately owned occurrences at False Bay, Davis Point, Bocker property, Ebey's landing, and West Beach are potentially threatened by development for residential or commercial use. Bocker property, Ebey's landing, and West Beach on Whidbey Island are zoned for residential development. False Bay on San Juan Island is designated as rural, indicating that the area is dominated by agricultural, forestry, and recreational uses. Such a zoning designation permits the extraction of sand, gravel, and mineral deposits, as well as residential development. The Davis Point population on Lopez Island is called a designated conservancy, which allows the construction of homes and the management of resources on a sustained-yield basis. Although no plans for development have been initiated at these sites, the habitats for these populations remain vulnerable to threats from adjacent areas that receive high human use and to the potential for future development.

Loss of suitable habitat from either encroachment of woody species or development in the areas surrounding these disjunct populations prevents expansion of the species and affords no refugia in the case of catastrophic events that affect existing populations. Because the grassland habitat in the areas surrounding the existing populations has been lost, it is highly doubtful that the populations will ever be able to expand naturally. The continued existence of golden paintbrush is therefore threatened by the absence of available habitat for recruitment and colonization.

Trampling by recreationists may threaten the Fort Casey State Park population because paths worn into the soil pass directly through the C. levi-secta site, although foot traffic and consequent trampling trampling by the public in this area have been reduced by a decorative fence erected in 1995. The few plants that formerly occurred in Beacon Hill Municipal Park in Victoria were located in a heavily used area of the park. Trampling by the public may have contributed to the extirpation of this population.

None of the occurrences on private ownerships has been fenced or is otherwise protected. The West Beach location is surrounded by beachfront homes and pedestrians pass directly through the golden paintbrush population to reach the beach. Adjacent property owners maintain their lawns with fertilizers and herbicides, and aerial drift containing these chemicals is a potential threat to this taxon if the chemicals contact individual plants. The population on the Bocker property is threatened by foot traffic from several new homes on the other side of the road. The only access to the beach from the resort at False Bay runs through the golden paintbrush location there, and individual plants alongside these footpaths have been trampled. Trampling has been also been documented at Ebey's landing, a recreation area where footpaths again lead to and through plants. The Ebey's landing occurrence is adjacent to a road on a steep hill slope overlooking the ocean. Erosion and slumping have occurred on the slope and potentially threaten the taxon at this location.

Golden paintbrush has no known commercial use, although it is vulnerable to spontaneous picking and collection at public sites because of its showy golden-yellow bracts. Fort Casey State Park, Bocker property, and Forbes Point are sites with high levels of public use where collection and trampling are threats. The Fort Casey State Park population is probably most at risk from overcollection because of its high level of recreational use. Visitor use has increased within the last decade, and park users have been observed picking the flowering plant. This population numbered about 230 plants in 1995, down from the more than 500 individuals that constituted its historical presence. C. levisecta may well become more vulnerable to collection by concerned citizens, amateur botanists, and the general public as a result of the increased publicity attendant upon federal listing.

Disease is not known to be a factor threatening this taxon, but populations may have been reduced from historical levels by predation, especially grazing by livestock and browsing by rabbits. Signs of grazing on the flowering stems of golden paint-brush, probably by rabbits and deer, has been noted at the Bocker property. Although the effect is unknown, grazing presumably affects seed number and reproductive viability. Livestock and exotic feral rabbits also graze the False Bay population. Heavy predation by rodents on herbaceous material and seeds at the Forbes Point site was noted in 1990 and 1991. Grazing also was observed at Forbes Point in 1984 and 1985. This predation may be reducing the reproductive potential at that site. At Fort Casey State Park, all flowering stems of a small colony of C. levisecta were eaten by rabbits during the spring of 1996, thus eliminating seed set and reproduction for that year.

The Rocky Prairie Natural Area Preserve has historically harbored a population of the Whulge checkerspot butterfly (Euphydryas editha taylori ), a state-sensitive species that is a potential seed predator. This threat is likely a low one because golden paintbrush is not a specific host and no individual butterflies were observed at the site during an observation in the 1990s. Insect larvae have been observed feeding on flowering parts of this plant. Although several species of caterpillar are known to prey on golden paintbrush, they are not believed to pose any long-term threat. Grazing and seed predation are two natural pressures historically faced by golden paintbrush, but populations that have been reduced or stressed due to other factors are less able to rebound after periods of heavy predation.

The golden paintbrush populations in Canada receive no regulatory protection. Legislation to protect endangered species has been proposed to the British Columbia government, but currently no federal or provincial law protects sensitive species. The Trial Islands, offshore from the city of Victoria, are designated as an ecological reserve by the British Columbia Ministry of Parks. The small population at Alpha Islet also is located within a designated ecological reserve. Ecological reserves are protected areas that generally require permits for entry and do not allow consumptive activities, like plant collection or other activities destructive to resources. The designation of ecological reserve does not, however, mandate specific management procedures for the plant. Because this designation is an administrative one, it could potentially be reversed by administrative decision, and the site could be used for other purposes.

Golden paintbrush is listed as threatened rather than endangered because four of the ten extant populations contain more than 1,000 plants and these locations are distributed across three Washington counties and into southwestern Canada. Several of the populations occur on sites designated as preserves or in areas that are afforded some level of protection through current management efforts from the threats outlined above.

Conservation and Recovery

Active management to benefit golden paintbrush is occurring at Rocky Prairie, Fort Casey, Forbes Point, and West Beach, although habitat management for this species is neither assured at each of these locations nor coordinated among and between the various population sites. The Rocky Prairie Natural Area Preserve has the highest level of protection of all golden paintbrush occurrences, and this site has been actively managed with prescribed burning to eliminate alien species and hand removal of invasive plants. Seven acres (2.8 hectares) of encroaching Douglas-fir were directionally felled and removed from Rocky Prairie during the winter of 1996, a protective activity accomplished under a cooperative agreement between the FWS and the state of Washington. Despite these efforts to restore prairie stucture, composition, and conditions by reducing shade on the site, continued funding of this restoration cannot be assured. Additionally, the efforts by the Washington Department of Natural Resources to eliminate the invasive Scotch broom (Cytisus scoparius ) and mouse-ear hawkweed (Hieracium pilosella ) at this site are also voluntary and not statutorially required.

Park managers at Fort Casey State Park have begun mowing, clipping, and removing vegetation to improve the conditions of the grassland habitat, while using protective fencing to restrict trampling of golden paintbrush plants. The Department of Defense is participating in the Washington Registry of Natural Areas Program. A navy staff biologist has undertaken measures to evaluate the status of the population on Forbes Point. Efforts have also been made to eradicate some invasive non-native species. A fence has been constructed to restrict people from trampling or picking the plants and to keep rabbits from browsing golden paintbrush; however, rodents still enter the fenced area and consume seed. Signs have been erected designating the site as a research area, but the navy does not prohibit public use of this site, which receives occasional foot traffic associated with a nearby popular beach.

The ELNHR was established by the combined efforts of the local landowners, the National Park Service, and the U.S. Congress to give recognition to the local landowners for maintaining their dwellings and landscapes in a specific historic fashion. The historic reserve designation serves as a form of covenant that restricts the type of landscaping and architectural design used for the maintenance or remodeling of any existing structures and for construction of new structures within ELNHR. The national historic reserve designation does not prohibit development or extraction of natural resources and provides no protection for biological resources. The National Park Service's jurisdiction over ELNHR is only advisory in nature and is limited to providing technical assistance to state and local governments and local landowners in the management, protection, and interpretation of the historic reserve. Although golden paintbrush is considered in the current management of the historic reserve, management is not specifically directed toward the long-term conservation of the plant. The populations of golden paintbrush at Ebey's landing and the Bocker property are also listed on the Washington Registry of Natural Areas. The Bocker property, owned by Seattle Pacific University within the designated boundary of ELNHR, is currently managed as a natural area used for education purposes with no active management to retain grassland habitat.

Contacts

U. S. Fish and Wildlife Service
Regional Office, Division of Endangered Species
Eastside Federal Complex
911 N. E. 11th Ave.
Portland, Oregon 97232-4181
Telephone: (503) 231-6121
http://pacific.fws.gov/

Western Washington Fish and Wildlife Office
U. S. Fish and Wildlife Service
510 Desmond Drive S.E., Suite 102
Lacey, Washington 98503-1291
Telephone: (360) 753-9440
Fax: (360) 753-9008

References

Agee, J. K. 1993. Fire Ecology of Pacific Northwest Forests. Island Press.

Gamon, J. G. 1995. "Report on the Status of Castilleja levisecta (Greenman)." Natural Heritage Program, Department of Natural Resources, Olympia, Washington.

Greenman, J. M. 1898. "Some New and Other Noteworthy Plants of the Pacific Northwest." Botanical Gazette, no. 25: 261-269.

U.S. Fish and Wildlife Service. 11 June 1997. "De-termination of Threatened Status for Castilleja levisecta (Golden Paintbrush)." Federal Register 62(112): 31740-31748.

Washington Natural Heritage Program. 1994. Endangered, Threatened and Sensitive Vascular Plants of Washington. Department of Natural Resources, Olympia, Washington.

Wentworth, Jane. 1994. "The Demography and Population Dynamics of Castilleja levisecta, an Endangered Perennial" (unpublished Master's thesis). University of Washington, 1994.

Wentworth, J. 1996. "Conservation Recommendations for Castilleja levisecta in Washington." Washington Natural Heritage Program, Washington Department of Natural Resources, Olympia.