The bright, warm colored bracts that enclose Indian paintbrush flowers capture the attention of pollinators and hikers alike. Golden paintbrush is no exception. Of the 42 paintbrush species in the Pacific Northwest, this is the only yellow-bracted one in its range (Eastman 1990). Populations of this species are rare and the fields glow radiantly when it blooms from April until June. Both federal and private players are vital in the conservation of the nine remaining populations in Washington and two remaining populations in British Columbia. Whidbey Island Naval Air Station monitors and manages a large population on its land. A private landowner, Robert Pratt, specified in his will that 147 acres of his estate, which contained a significant golden paintbrush population, would go to a nonprofit conservation group. Upon his death in 1999, The Nature Conservancy acquired this land and worked with the National Park Service to purchase another 380 adjoining acres. Congress appropriated funds for the Pratt reserve, and The Nature Conservancy borrowed the remaining money needed to expedite this purchase. In southern Vancouver Island, the Garry Oak Ecosystems Recovery Team is working to save over 100 endangered species, including golden paintbrush. These efforts are essential for the continued survival of golden paintbrush. In the absence of active management, fairly vigorous populations of Castilleja levisecta have rapidly declined to extinction within a few decades. Alarmingly, these declines did not result from overt habitat destruction, but from the 'invisible' threats associated with low population numbers, fire-suppression and weed invasion. Presently, no site contains enough golden paintbrush individuals to be immune to drastic, irreversible declines. Therefore, steps to increase population sizes and establish new populations are necessary to ensure long term survival of golden paintbrush. The University of Washington's Center for Urban Horticulture, also a Participating Institution of the Center for Plant Conservation, is actively involved in these efforts. Indian paintbrush plants actively absorb selenium, a mineral that is toxic in high concentrations (Tillford 1997). A currently unexplored use of Indian paintbrush might be reclamation of land with toxic amounts of selenium. Golden paintbrush, which can grow in dense stands, may be especially useful for this purpose.
|Common Names||Golden Indian Paintbrush | Golden Paintbrush|
|Associated Scientific Names||Castilleja levisecta|
|Distribution||Historically, golden paintbrush was found as far north as the Puget Trough of Washington and some islets of British Columbia, and as far south as the Willamette Valley of Oregon. Today, there are 11 populations remaining on islands near the Straits of Juan de Fuca; one site near Olympia, WA; and the San Juan Islands off the coast of British Columbia, where a majority of the populations are (Arnett 2009).|
This endangered taxon is found in open grasslands (USFWS 1997), often on glacially derived soils: specifically, gravelly glacial outwash or on clayey glacio-lacustrine sediments in outcrops (Gamon et al. 2000). Areas that are moist in the winter but not inundated with water are most preferable (Meinke 1982). Typically, golden paintbrush grows at elevations below 100 m (Gamon et al. 2000).
Evans et al. (1984) reported that a species of bumblebee (Bombus californicus) was observed visiting Castilleja levisecta and pollen can be observed on the bee's head as it exits the inflorescence (USFWS 2000). Evans et al. (1984) raised the possibility that the Rocky Prairie site may have too few bumblebees to pollinate the entire population. The bumblebee population could have declined as a result of successional changes, disturbances to the bumblebee's habitat, or pesticide application or drift (USFWS 2000).
Castilleja levisecta is native to prairies that are dependent on occasional fires to prevent succession to woody plant communities (Evans et al. 1984). Preliminary burn studies indicate that C. levisecta performs better after burn treatment. This increase likely results from both a decreased mortality of existing plants, and an increase in recruitment and establishment of seedlings in the absence of shading by Douglas-Firs and shrubs. Additionally, nutrient release from ashes may increase fitness. This higher survival rate is likely due to nutrient release from ashes and decreased competition (Dunwiddie et al. 2000). Improved germination rates following heat treatment indicate that C. levisecta may be fire adapted with a mechanism to promote germination following a burn, when conditions for establishment are favorable. It is important to note that increased browsing by mammals might to some degree offset the positive effects of burning. Additionally, the invasive exotic species Hieracium pilosella may also be stimulated by burn activity (Dunwiddie et al. 2000).
Castilleja levisecta is a hemiparasite. Its leaves contain chlorophyll and are capable of conducting photosynthesis, but golden paintbrush plants are also capable of parasitizing the roots of other plants to extract water and nutrients (Evans et al. 1984). Present research indicates that C. levisecta does not require this parasitic relationship to survive. However, this relationship could influence C. levisecta's competitive ability and seedling establishment. Subsequently the presence of host plants may be significant in recovery efforts.
Often, this herb is associated with Festuca idahoensis and F. rubra (Wentworth 2000).
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