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Engaewa reducta

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Taxonomy [top]

Kingdom Phylum Class Order Family
ANIMALIA ARTHROPODA MALACOSTRACA DECAPODA PARASTACIDAE

Scientific Name: Engaewa reducta
Species Authority: Riek, 1967
Common Name(s):
English Dunsborough Burrowing Crayfish

Assessment Information [top]

Red List Category & Criteria: Endangered B1ab(iii,iv) ver 3.1
Year Published: 2010
Date Assessed: 2010-06-01
Assessor(s): Burnham, Q.
Reviewer(s): Collen, B. & Richman, N.
Contributor(s): Livingston, F., Livingston, F., Soulsby, A.-M., Batchelor, A., Dyer, E., Whitton, F., Milligan, H.T., Smith, J., Lutz, M.L., De Silva, R., McGuinness, S., Kasthala, G., Jopling, B., Sullivan, K. & Cryer, G.
Justification:
Engaewa reducta has been assessed as Endangered under criteria B1. This species has an extent of occurrence of 450 km2, and a severely fragmented distribution. Fragmentation of habitat has been caused by cattle grazing and large-scale water abstraction. The subpopulation at the type locality has already been extirpated as a result of these threats. Conservation measures are urgently needed to protect some of the swamps in which this species is found from further lowering of the water table.

Geographic Range [top]

Range Description: This species is endemic to the Dunsborough region in Western Australia, and has a restricted distribution. This species is known from several swamps between Dunsborough and Margaret River. It is unknown whether altitude is potentially a limiting factor in the distribution of this species (Q. Burnham, pers. comm. 2008). The extent of occurrence (EOO) of this species has been estimated at 465 km2.
Countries:
Native:
Australia (Western Australia)
Range Map: Click here to open the map viewer and explore range.

Population [top]

Population: Historical records show that some populations which existed 20 - 40 years ago, no longer exist (Q. Burnham pers. comm. 2008). It is thought to be common in relation to other species in sites where it is found (Q. Burnham pers. comm. 2008).
Population Trend: Unknown

Habitat and Ecology [top]

Habitat and Ecology: This is a primary burrowing species which digs expansive burrow systems in sandy soils and is found in seasonal wetlands where the water table may or may not reach the surface (Q. Burnham pers. comm. 2008).


Systems: Freshwater

Threats [top]

Major Threat(s): This species is known only from a few swamps, it is absent from the type locality, and the habitat of this species is isolated and severely fragmented. Other threats include cattle grazing and hydrological change due to damming of water courses for vineyards (Horwitz and Adams 2000). Rapid changes in land use within this species range, has affected surface and ground water conditions in the south-west, destroying natural habitat (Naturebase 2007). Any large-scale perennial extraction of groundwater falls into one of the major categories of threats posed to the freshwater crayfish of the region (Morgan and Beatty 2005).

Conservation Actions [top]

Conservation Actions: There are no conservation measure in place to protect this species at present. It is state-listed as 'vulnerable' and protected under the Western Australia Wildlife and Conservation Act (1950). Horwitz and Adams (2000) have recommended that this species should be classed as Endangered using B criteria. Further research into the abundance and appropriate conservation measures are required for this species. This species is likely to occur within the Haag Nature Reserve which is roughly 10 km south of Dunsborough (Q. Burnham, pers. comm. 2008). A recovery plan is in the process of being formulated, as this species is listed within the state and is currently under federal review (Q. Burnham, pers. comm. 2008).

Citation: Burnham, Q. 2010. Engaewa reducta. The IUCN Red List of Threatened Species. Version 2014.2. <www.iucnredlist.org>. Downloaded on 01 October 2014.
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