Wednesday, June 10, 2015

Threatened and Endangered Species of the Williamette Valley Prairie Savannas

There are 6 listed species endemic to the ecoregion.

Fender's Blue butterfly (E) (Icaricia icarioides fenderi)
Willamette daisy (E) (Erigeron decumbens var. decumbens)
Bradshaw's desert-parsley (E) (Lomatium bradshawii)
Kincaid's Lupine (T) (Lupinus sulphureus ssp. kincaidii)
Nelson's checker-mallow (T) (Sidalcea nelsoniana)
Golden Paintbrush (T) (Castilleja levisecta) - extirpated from Williamette valley

Several other nonlisted species are also considered sensitive:

Taylor’s (whulge) checkerspot butterfly, Euphydryas editha taylori
Pale larkspur, Delphinium leucophaeum
Willamette Valley larkspur, Delphinium oreganum
Peacock larkspur, Delphinium pavonaceum
Shaggy horkelia, Horkelia congesta ssp. congesta
White-topped aster, Sericocarpus rigidus
Hitchcock’s blue-eyed grass, Sisyrinchium hitchcockii

There are two major rare habitats in the Williamette valley responsible for the listed and sensitive species: upland prairies and wet prairies. Prairies are dependent on disturbance to prevent succession, and many have been either plowed under or allowed to develop into forests or shrublands.  A recovery plan extends throughout the Williamette valley, and south of Roseburg to the Douglas county line to include a third disjunct habitat in the Umpqua valley.  

The plant composition of upland prairies is dominated by bunchgrasses, including Festuca idahoensis, Danthonia californica, Elymus glaucus, Achnatherum lemmonii, and Koeleria macrantha.  The spaces between the bunchgrasses are typically covered by mosses, fruticose lichens, or native forbs. Showy, slow-growing perennial forbs include Eriophyllum lanatum, Potentilla gracilis, Fragaria virginiana, Sidalcea malviflora, and Symphotrichum (=Aster) hallii, and the bulbs Calochortus tolmiei and Dichelostemma congestum. Some fast-growing annual forbs, including various species of tarweed (Madia spp.) and Clarkia, are also prominent members   The main threat are vegetatively spreading non native grasses included Agrostis, Festuca, as well as Rubus (blackberry).

Wet praries are dominated by herbs. Deschampsia cespitosa (tufted hairgrass),and tufted microhabitats. Non-native Agrostis and Cirsiums are threat.

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