Taxonomy [top]

Kingdom Phylum Class Order Family
Animalia Annelida Clitellata Haplotaxida Megascolecidae

Scientific Name: Driloleirus macelfreshi
Species Authority: (Smith, 1937)
Common Name(s):
English Oregon Giant Earthworm

Assessment Information [top]

Red List Category & Criteria: Endangered B1ab(iii) ver 3.1
Year Published: 2014
Date Assessed: 2013-07-10
Assessor(s): Blakemore, R.
Reviewer(s): Gerlach, J.
This species has a restricted range and has probably declined significantly over the past 200 years. It has an extent of occurrence of 3,500 km2 and occurs at five locations. It is currently thought to be threatened by habitat degradation, chemical pollution and possibly competition by invasive earthworm species, which are causing a continuing decline in the habitat quality. Therefore, it is assessed as Endangered.
Previously published Red List assessments:
1996 Vulnerable (VU)
1994 Endangered (E)
1990 Endangered (E)
1988 Endangered (E)
1986 Endangered (E)
1983 Endangered (E)

Geographic Range [top]

Range Description: This species is restricted to the state of Oregon, USA. Recently it has only been recorded from the bottomlands of the Willamette Valley. It has been recorded from 16 sites: 15 sites within the Willamette Valley and one site in the Oregon Coast Range (Lincoln, Linn, Marion, Polk and Yamhill counties and Benton County). It is expected to occur in Lane County,  the Siuslaw National Forest and in the Salem District and Eugene District of the Willamette Valley.
Countries occurrence:
United States (Oregon)
Estimated area of occupancy (AOO) - km2: 1000
Number of Locations: 5
Lower elevation limit (metres): 40
Upper elevation limit (metres): 150
Range Map: Click here to open the map viewer and explore range.

Population [top]

Population: No data are available on the population.
Current Population Trend: Unknown
Additional data:
Continuing decline of mature individuals: Unknown
Extreme fluctuations: Unknown Population severely fragmented: Unknown

Habitat and Ecology [top]

Habitat and Ecology: The Oregon giant earthworm (up to 1.32 m) burrows in fine clay rich soils. It is associated with undisturbed soil in forests of Douglas firs, grand firs, and bigleaf maples and may prefer well drained but damp soils. It is active near the surface but its permanent burrows may be as deep as 4.6 m below the surface.
Systems: Terrestrial
Continuing decline in area, extent and/or quality of habitat: Yes

Threats [top]

Major Threat(s): Habitat loss and the establishment of introduced earthworms are the main threats. Less than one percent of the original habitat area remains due to conversion to development and conversion to agricultural land. Remaining habitat contains invasive earthworm species which may compete with the Oregon giant earthworm. There is also pollution from chemicals applied to nearby agricultural land and from forestry management.

Conservation Actions [top]

Conservation Actions:

It is not specifically protected. It is listed as a BLM Bureau Sensitive Species. Better survey methods need to be developed for this species.

Citation: Blakemore, R. 2014. Driloleirus macelfreshi. The IUCN Red List of Threatened Species 2014: e.T6829A21416138. . Downloaded on 04 October 2015.
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