Taxonomy [top]

Kingdom Phylum Class Order Family
Animalia Arthropoda Malacostraca Decapoda Parastacidae

Scientific Name: Euastacus clarkae
Species Authority: Morgan, 1997
Common Name(s):
English Ellen Clark’s Crayfish

Assessment Information [top]

Red List Category & Criteria: Critically Endangered B1ab(iii)+2ab(iii) ver 3.1
Year Published: 2010
Date Assessed: 2010-06-01
Assessor(s): Furse, J. & Coughran, J.
Reviewer(s): Collen, B. & Richman, N.
Contributor(s): 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.
Euastacus clarkae has been assessed as Critically Endangered under criterion B1ab(iii)+2ab(iii). This species has an extent of occurrence less than 10 km2, and area of occupancy almost certainly smaller than the extent of occurrence, and is known from a single location. It is impacted by a range of threats including predation by exotic species, and habitat degradation due to logging. Research efforts are urgently required to better understand the biological and ecological requirements of this species, along with the severity of threats on the rate of population decline before suitable conservation measures can devised.

Geographic Range [top]

Range Description:

This species has been collected from two nearby tributaries in Mount Boss State Forest, near Mount Werrikimbe in New South Wales (Morgan 1997). The species is restricted to rainforest habitat above 600 m above sea level. The extent of occurrence is less than 10 km2 (J.M. Furse and J. Coughran pers. comm. 2008), and area of occupancy is almost certainly less than this.

Countries occurrence:
Australia (New South Wales)
Estimated area of occupancy (AOO) - km2: 0-10
Number of Locations: 1
Lower elevation limit (metres): 600
Range Map: Click here to open the map viewer and explore range.

Population [top]

Population: There is no population information available for this species.
Current Population Trend: Unknown
Additional data:
Population severely fragmented: Unknown

Habitat and Ecology [top]

Habitat and Ecology: This species is found in cool, shaded streams more than 670 m above sea level. Rainforest is found along the banks and dry sclerophyll on exposed ridges (Morgan 1997).

The slow growth rate and low fecundity of many Euastacus renders them less resilient to reduction in population numbers through habitat destruction and catastrophic events (Van Praagh 2003).

Systems: Freshwater

Threats [top]

Major Threat(s): This species is susceptible to localized impacts, including logging (resulting sedimentation), bush fires, forest management practices, habitat destruction and over-exploitation by collectors. It is also susceptible to climate change, including increasing temperature, alterations to hydrological regimes, severe weather events, loss of suitable rainforest habitat and increased potential for bushfires (Chiew and McMahon 2002, Howden 2003, Hughes 2003, Pittock 2003, Hennessy 2006, Westoby and Burgman 2006, IPCC 2007).

This species may also be potentially threatened by Cane Toads (Rhinella marina) (DEH 2004a) although there are no specific data on impacts for this species. Other exotic species (cats, foxes, pigs, goats) that have generally been found to impact on crayfish (e.g. Green and Osbourne 1981, Horwitz 1990, Merrick 1995, Eyre et al. 1997, ACT Government 2007, O'Brien 2007) also occur in this species' range (DEH 2004b,c,d,e). Given the highly restricted distribution of this crayfish species, these exotic species could contribute to serious declines in distribution and/or local abundance. Due to the narrow thermal tolerance of this species, and its restricted range (restricted to cool, headwater streams in forested catchments), global temperature increase has resulted in range contraction. This species is further compromised by the presence of exotic species (goats, feral pigs and cats) which are known to predate on crayfish and degrade riparian habitat; while the precise effects of these threats on this species are not yet well understood, they are believed to be significantly impacting the long term viability of the population (J. Furse and J. Coughran pers. comm. 2010).

Conservation Actions [top]

Conservation Actions:

There are no conservation measures in place specifically for Euastacus clarkae. However, its distribution is within State Forest, so there is the potential for some degree of habitat protection within the species limited range. In the future, the threat processes affecting localised populations of this species need to be monitored to ensure they do not become more widespread and result in significant losses.

Research should be initiated to include population assessment and monitoring, biological and life history information, habitat requirements, investigations into thermal tolerance, resilience to exotic species, susceptibility to forest management and logging impacts. In New South Wales, a minimum recreational size limit of 90 mm OCL is in place for any spiny crayfish (NSW DPI 2007). Euastacus clarkae does not attain that size, and so is indirectly protected by this restriction.

Citation: Furse, J. & Coughran, J. 2010. Euastacus clarkae. The IUCN Red List of Threatened Species 2010: e.T153666A4529124. . Downloaded on 07 October 2015.
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