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Kincaid's lupine, aka Oregon lupine

Kincaidlupine,FWS

Scientific name: Lupinus oreganus, Oregon lupine

Status: Threatened

Critical Habitat: Designated

Listing: Kincaid's lupine was federally listed as threatened in 2000. Critical habitat was designated in 2006.

  • Description and Life History

    Kincaid’s lupine is the primary larvae food plant for the Endangered Fender blue butterfly (Icaricia icarioides fenderi), which is found only in Oregon. It is used by the Puget blue butterfly ((Icaricia icarioides blackmorei) in Washington State.

    Kincaid's lupine is a perennial species in the pea family (Fabaceae). Kincaid's lupine is distinguished from other species of lupine because it is relatively low growing (30-50 cm tall), rhizomatous, many stems and an unbranched flower stalk. Its aromatic flowers are light blue to purple or yellowish to cream colored. Its leaves are palmately compound (5 lobes radiating out of single point); basal leaves are usually present until flowering. Flowering typically occurs from April to June. Fruit pods are hairless, 2-3 cm long; generally with 4-5 seeds that may be pinkish brown to black.  Seeds are dispersed from fruits that open explosively upon drying.

    Habitat and Range

    Kincaid's lupine is known to occur in native upland prairies and open oak woodlands.  It is regionally endemic from Douglas County, Oregon north to Lewis County, Washington. The species is extirpated from British Columbia. In its native prairie setting, Kincaid's lupine is typically found growing with bunchgrasses and native forbs including Roemer’s fescue (Festuca roemeri), red fescue (Festuca rubra). Other important indicator species include Tolmie's mariposa (Calochortus tolmiei), Hooker's catchfly (Silene hookeri), broadpetal strawberry (Fragaria virginiana), rose checker-mallow (Sidalcea virgata), and common lomatium (Lomatium spp.). Upland fescue- dominated prairies make up the majority of habitat for Kincaid's lupine. The plant's distribution implies a close association with native upland prairies that are characterized by heavier soils and mesic to slightly xeric soil moisture levels. At the southern limit of its range, this species may occur on well-developed soils adjacent to serpentine outcrops (high in magnesium, iron and certain toxic metals) where it is often found under scattered oaks.

    Reasons for Decline

    Native prairie has been virtually eliminated from most of the species’ range as a result of conversion to agriculture, urbanization, and other development. Most west-side prairies are early seral (early stage in a sequential plant community progression) requiring natural or human-induced disturbance for their maintenance. Grasslands by nature are a transient community which require disturbance to prevent transition to woody plants, both shrubs and forest. Native Americans maintained upland prairies of Oregon and Washington Willamette Valley by the use of prescribed fire  prior to European settlement. With the suppression of frequent prescribed fire, the regular disturbances that maintained native prairies were altered, allowing woody plants to invade the prairie and shade out the low-growing Kincaid's lupine.  In addition, nonnative species such as Himalayan blackberry (Rubus discolor) and Scot’s broom aggressively overtake open prairie plant communities and crowd out native species.

    Loss of native prairies resulted in fragmentation of prairies that supported Oregon lupine populations which were once more closely connected. As the number of prairies declined, the distance between prairies increased, and the opportunity for seed dispersal between populations became much reduced.  Isolated  populations  face a higher chance of extirpation from stochastic events, since they are no longer part of a larger, more stable population that was likely more resilient.

    Conservation Measures

    Natural processes that function to maintain open prairies have been altered to the point that intervention is needed to prevent further loss. Historically, periodic prescribed fires played a role in maintaining prairies in an open condition.   Today, prairie remnants are no longer maintained by fire due to suppression efforts. Where possible, prescribed, controlled burning, mowing and hand clearing and the judicious use of herbicides are used to manage the prairie ecosystem. However, Oregon (Kincaid's) lupine is host to the endangered Fender's blue butterfly; thus, management actions have to be carefully planned in order to avoid harming the butterfly larvae.  The most common strategy is to burn no more than one-third of the habitat patch occupied by the butterfly, its eggs or larvae.

    References

    U.S. Fish and Wildlife Service. 2000.  Endangered Status for Erigeron decumbens var. decumbens (Willamette Daisy) and Fender's Blue Butterfly (Icaricia icarioides fenderi) and Threatened Status for Lupinus sulphureus ssp. kincaidii (Kincaid's Lupine). Federal Register 65:3875-3890.

    Camp, Pamela and John G. Gamon. 2011.  Field guide to the Rare Plants of Washington. University of Washington Press.  Seattle and London. 392 pp.

     

     

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