Driloleirus americanus 

Scope: Global
Language: English

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Taxonomy [top]

Kingdom Phylum Class Order Family
Animalia Annelida Clitellata Megadrilaceae Megascolecidae

Scientific Name: Driloleirus americanus Smith, 1897
Common Name(s):
English Giant Palouse Earthworm, Washington Giant Earthworm

Assessment Information [top]

Red List Category & Criteria: Vulnerable B2ab(iii); D2 ver 3.1
Year Published: 2014
Date Assessed: 2013-07-07
Assessor(s): Blakemore, R.
Reviewer(s): Gerlach, J.
The species is associated with one type of habitat that is highly restricted and deteriorating in quality due to agricultural clearance, pesticide pollution, suburban development and invasive species. It has an area of occupancy (AOO) of 1,074 km2 and is known from a single location. Therefore, it is assessed as Vulnerable.
Previously published Red List assessments:

Geographic Range [top]

Range Description:This species is present in the west-central Idaho and southeast Washington, USA. It has only recently been recorded in Idaho.

Countries occurrence:
United States (Idaho, Washington)
Additional data:
Estimated area of occupancy (AOO) - km2:1074
Number of Locations:1
Range Map:Click here to open the map viewer and explore range.

Population [top]

Population:It was reported to be "very abundant" in 1897, the giant Palouse earthworm has only recently been recorded in 1988 and 2005. Surveys in 2002 failed to locate the species and it is thought to be very rare, in contrast to historical reports. The population is assumed to be declining but no quantitative data are available.
Current Population Trend:Decreasing
Additional data:
Continuing decline of mature individuals:Unknown
Extreme fluctuations:UnknownPopulation severely fragmented:Unknown

Habitat and Ecology [top]

Habitat and Ecology:It is associated with 'Palouse' grassland habitats. It is a burrowing species, reported to burrow in soil down to a depth of three metres.
Continuing decline in area, extent and/or quality of habitat:Yes

Threats [top]

Major Threat(s): The Palouse habitats that the earthworm is associated with have been reduced to 1% of their original extent and the remnants are threatened by agricultural clearance and pesticide pollution, suburban development and invasive species.

Conservation Actions [top]

Conservation Actions: The main remaining habitat areas in Washington State are protected. An attempt to have the species listed for protection was rejected in 2007.

Citation: Blakemore, R. 2014. Driloleirus americanus. The IUCN Red List of Threatened Species 2014: e.T6828A21416080. . Downloaded on 19 August 2018.
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