The following Participating Institutions are custodians for this species in the CPC National Collection:
University of Minnesota Landscape Arboretum
The conservation of Lupinus sulphureus ssp. kincaidii is fully sponsored.
Christa von Behren and Ed Guerrant contributed to this Plant Profile.
Kincaids lupine, like many other species, is suffering from rapid decline in suitable habitat. Conversion of Willamette and Douglas Valley grasslands to agricultural lands has reduced the lupine to 57 sites, most of which are small and isolated. Fenders blue butterfly, and endangered butterfly endemic to the Willamette Valley, is heavily reliant on Kincaids lupine. The importance of the lupine for the survival of the butterfly has made the plant an important conservation target.
Kincaids lupine has purple to white flowers that rapidly fade to brown. The plant flowers from April through June and is pollinated by insects. It is a low-growing plant that has been found to live as long as 25 years. While the lupine lacks vegetative propagules, distant flowering stalks are often connected by underground stems. Research suggests that this underground connection can lead to inbreeding when plants only receive pollen from within the same colony.
Invasive plants can cause problems for Kincaids lupine. The plant is intolerant of prolonged shade, and can easily be shaded out by these taller plants. Controlled burning and mowing of prairie plots are used to remove invasive species and restore lupine habitats. These techniques have been found to increase lupine cover in addition to the number of Fenders blue butterfly eggs found in the habitat.
Distribution & Occurrence
· Found at low elevations in the Willamette and Umpqua Valley, OR and Lewis County, WA (USFWS).
· Found in open prairies and oak woodlands on mesic to slightly xeric soils (WHNP and BLM 1999).
· The lupine is unable to survive in prolonged shade (Wilson et al. 2003).
· At the southern limit of its range, Kincaids lupine occurs adjacent to serpentine outcrops (OFW 2007).
Conservation, Ecology & Research
Kincaids lupine flowers from April through June (WHNP and BLM 1999). The flowers of Kincaids lupine have a pump arrangement for cross-pollination. A string of pollen is pushed through the tip of the keel by the stigma when the pistil comes under pressure during an insect visit (Kaye 1999). Pollination of the flower is mainly by small bees (Wilson et al. 2003).
Kincaids lupine is the main food source for the larval stage of Fenders blue butterfly (Icaricia icarioides fender Macy) an endangered butterfly species endemic to Oregon. Adult butterflies lay their eggs on host plants in May and June. The eggs are oviposited on the undersides of the lupine leaves (Kaye and Thorpe 2006). The caterpillars feed and develop on the plants until the following spring when they transform into adult butterflies (USFWS 1998). Because the lupine can be very long-lived, it provides long-term stability for butterfly populations, allowing them to exist in single locations for long periods of time (Schultz et al. 2003).
Insect herbivory can affect the reproduction success of Kincaids lupine. Predation can destroy flowers and prevent the development of fruits. Some insects, such as the silvery blue butterfly, also feed on the fruits, causing seed mortality (Wilson et al. 2003). Larvae of the Fenders blue butterfly often feed on the young leaves and apical meristems of the lupine, resulting in clusters of damaged leaves and stems (Kaye and Thorpe 2006).
· While seed scarification has been found to improve germination success (Kaye and Kuykendall 2001), one study found that no fitness benefits were gained from scarification in seeds sown in autumn. Scarification was also not found to increase the survivorship of plants after germination (Severns 2003a).
· In the West Eugene Wetlands, mowing of prairie plots resulted in reduction in blackberry and an increase in lupine leaf, flower, and foliar cover. Mowed plots also had higher numbers of Fenders blue butterfly eggs laid in them and higher egg-to-larva survival rates than unmowed plots did (Kaye and Thorpe 2006).
· Results from a study of restoration of habitat for the Fenders blue butterfly suggest that for Kincaids lupine, transplanting young seedlings may be more successful than sowing the lupine as seeds (Schultz 2001).
· A study on inbreeding in Kincaids lupine populations found that seed set and quality were significantly lower on plants receiving pollen from within the colony than on outcrossed racemes. Because of the plants vegetative potential, outcrossing may require pollen from distances than 10 m. Seed set was also found to increase with the number of patches, suggesting that smaller population sizes can reduce lupine reproduction. Results suggest that conservation of Kincaids lupine may depend on population augmentation, in which planting individuals from different sources facilitates outcrossing between populations (Severns 2003b).
· In a pollination experiment, plants did not set viable seed in the absence of insect pollinators, suggesting that the pollinators are required for seed production (Kaye 1999).
· In a propagation study, lupine establishment success was found to vary among restoration sites. Restoration sites closest to existing lupine success had the highest establishment success, with 10% and 17% survival rates, while a site more distant from an existing site had only 4% survivorship. Results also showed that the early life stages are the most vulnerable periods for the plant (Severns 2003a).
· A study of resource requirements for the Fenders blue butterfly found that butterfly density is positively associated with lupine leaf density. Results are suggestive of a threshold effect; the butterfly may require a minimum percent lupine cover to maintain high population density (Schultz and Dlugosch 1999).
· Seeds collected in 1987 through 2004 from multiple sites are stored in the Berry Botanic Garden seed bank.
· Phylogenetic studies to understand the relationships to other lupine taxa and the genetic diversity within the species. Hypotheses about the causes of inbreeding depression should also be tested (Wilson et al. 2003).
· Information on the longevity of seed in the soil seed bank and adult survival rates and longevities (Wilson et al. 2003).
· Quantify and compare impacts of disease, insect herbivory, weed competition and effects of symbiotic mycorrhizal fungi and nitrogen-fixing bacteria (Wilson et al. 2003).
· Information on site-specific variables that affect establishment is needed for the proper identification of restoration sites (Severns 2003a).
· Information on outbreeding depression, optimal outcrossing distances, and the effects of inbreeding depression (Severns 2003a).
Washington Natural Heritage Program Department of Natural Resources and Spokane District U.S.D.I. Bureau of Land Management. 1999. Field Guide to Washingtons Rare Plants. Washington Natural Heritage Program Department of Natural Resources and Spokane Dis