Home/Species/ Koehler's Rockcress

Boechera koehleri

(Howell) Al-Shehbaz

Koehler's Rockcress

G3Vulnerable Found in 9 roadless areas NatureServe Explorer →

G3VulnerableGlobal Rank

Identity

Unique IDELEMENT_GLOBAL.2.156758

Element CodePDBRA060Z0

Record TypeSPECIES

ClassificationSpecies

Classification StatusStandard

Name CategoryVascular Plant

Endemicendemic to a single nation

KingdomPlantae

PhylumAnthophyta

ClassDicotyledoneae

OrderCapparales

FamilyBrassicaceae

GenusBoechera

Synonyms

Arabis koehleriT.J. Howell

Concept Reference

Kartesz, J.T. 1994. A synonymized checklist of the vascular flora of the United States, Canada, and Greenland. 2nd edition. 2 vols. Timber Press, Portland, OR.

Taxonomic Comments

FNA (vol. 7, 2010) does not recognize distinct varieties within the species and moves it to the genus Boechera.

Conservation Status

Review Date1999-12-07

Change Date2000-01-19

Edition Date1999-12-07

Edition AuthorsVrilakas, Sue

Range Extent250-20,000 square km (about 100-8000 square miles)

Number of Occurrences21 - 80

Rank Reasons

Looking at the full species, Arabis koehleri has at least 70 occurrences with plant numbers between 3000-10,000. Most of these are found in two counties in Oregon with less than ten known occurrences in California. The threat of mining is not immediate but has the potential to cause widespread destruction. The type variety (Arabis koehleri var. koehleri) is rarer (only nine known occurrences) and with more immediate threats having the potential to impact a substanial percentage of this taxon's population.

Range Extent Comments

The range of Arabis koehleri is Douglas County, Oregon south to Josephine County, Oregon and the adjacent California county, Del Norte. Arabis koehleri var. stipitata occurs in Josephine County, Oregon and Del Norte County, California. Arabis koehleri var. koehleri is found only in Douglas County in the Umpqua River Valley.

Occurrences Comments

There is at least an estimated 70 occurrences. Nine occurrences are reported for variety koehleri, sixty-six for variety stipitata (Oregon reports). Because the Oregon Natural Heritage Program (ORNHP) stopped tracking variety stipitata, information on this variety has been sporadic. Arabis koehleri var. koehleri is an Oregon endemic and considered very rare so the Oregon Natural Heritage Program is confident about the number of occurrences. In California, Arabis koehleri var. stipitata is known from about six sites. The variety stipitata is somewhat difficult to identify, occurs in many, quite inaccessible areas, and is only obvious while blooming, which can be for a few weeks during some years. Because of this, it is probably more widespread than it appears (Kagan 1988).

Threat Impact Comments

The main threat to Arabis koehleri var. stipitata is mining activities on serpentine soils. Due to its rather inaccessible habitat, it appears to be self-protected from timber activities and cattle grazing. Because most of the populations of Arabis koehleri var. koehleri are on cliffs near roads and rivers near the city of Roseburg, threats are from road construction, rock quarry activities, herbicide spraying, dam construction, trampling from recreationalists, and grazing from feral goats.

Ecology & Habitat

Habitat

The two varieties of Arabis koehleri grow in different habitats. Variety stipitata occurs on serpentine substrate in areas with no or little soil development, often on steep slopes and cliffs, within Jeffrey pine (Pinus jeffreyi) plant associations at low to mid-elevations. Variety koehleri is found on open basalt rock outcrops and cliffs with grassland-type communities.

Other Nations (1)

United StatesN3

Province	Rank	Native
California	S3	Yes
Oregon	S3	Yes

Plant Characteristics

Economic Value (Genus)No

Roadless Areas (9)

California (6)

Area	Forest	Acres
Blue Creek Rare I	Six Rivers National Forest	12,134
Kelly	Six Rivers National Forest	5,195
Monkey Creek	Six Rivers National Forest	9,017
North Fork Smith	Six Rivers National Forest	37,898
Packsaddle	Six Rivers National Forest	3,862
Siskiyou B	Six Rivers National Forest	18,871

Oregon (3)

Area	Forest	Acres
North Kalmiopsis	Siskiyou National Forests	91,560
Shasta Costa	Siskiyou National Forests	14,420
South Kalmiopsis	Siskiyou National Forests	104,477

References (3)

Flora of North America Editorial Committee (FNA). 2010. Flora of North America north of Mexico. Vol. 7. Magnoliophyta: Salicaceae to Brassicaceae. Oxford University Press, New York. xxii + 797 pp.
Kagan, J. 1988. Draft species management guide for <i>Arabis koehleri var. stipitata</i>. Challenge cost share for U.S. Forest Service. Unpublished document on file at Oregon Natural Heritage Data Base, Portland, Oregon.
Kartesz, J.T. 1994. A synonymized checklist of the vascular flora of the United States, Canada, and Greenland. 2nd edition. 2 vols. Timber Press, Portland, OR.