Euastacus simplex 

Scope: Global
Language: English

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Taxonomy [top]

Kingdom Phylum Class Order Family
Animalia Arthropoda Malacostraca Decapoda Parastacidae

Scientific Name: Euastacus simplex Riek, 1956

Assessment Information [top]

Red List Category & Criteria: Vulnerable B1ab(iii) ver 3.1
Year Published: 2010
Date Assessed: 2010-06-01
Assessor(s): Coughran, J. & Furse, J.
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.

Euastacus simplex has been assessed as Vulnerable B1ab(iii). This species has a severely fragmented distribution, and an extent of occurrence of 15,000 km2. There has been a continuing decline in the quality of habitat due to the destructive nature of a number of exotic species in the area, some of which also predate upon this species. There is also destruction of suitable rainforest habitat in parts of its range. This species also faces the consequences of global temperature rise. As a restricted range species, dependent on cool, clear headwater streams, a slight increase in temperature could rapidly extirpate this species. Research should be initiated to include population assessment and monitoring, biological and life history information, habitat requirements, and resilience to effects of exotic species.

Geographic Range [top]

Range Description:

This species is endemic to Australia. It ranges from 25 km West of Dorrigo, 90 km to the Armidale and Guyra areas of New South Wales and one individual was found near Yarro, which suggests the species extends south along the Botumbella Range for a similar distance (J. Coughran and J.M. Furse pers. comm. 2009). Major drainage systems include the Nymboida, Styx, and Guy Fawkes Rivers in the North and the Hastings River in the South (Morgan 1997). It is a high altitude species, restricted to sites above 1100 m above sea level (Morgan 1997). As a highland species, it inhabits upper reaches of different drainages, and the species can thus be considered severely fragmented across its range due to the barrier effects of mountain ridges and unsuitable habitat in the intervening lowlands (Morgan 1997, Ponniah and Hughes 2006). This species has an estimated extent of occurrence of 15,000 km2.

Countries occurrence:
Australia (New South Wales)
Additional data:
Range Map:Click here to open the map viewer and explore range.

Population [top]


This species is known to be relatively abundant within sites it is known from (J. Coughran and J.M. Furse pers. comm. 2009).

Current Population Trend:Unknown
Additional data:
Population severely fragmented:Yes

Habitat and Ecology [top]

Habitat and Ecology:

This species is found in small to medium sized open streams with banks vegetated by sclerophyll forest and heath, or largely cleared for pasture at elevations between 1,100 m and 1,380 m above sea level. The water within its known habitat is clear and cool with brown algal growth (Morgan 1997).


Threats [top]

Major Threat(s):

This species is fairly tolerant to clearing (Morgan 1997); it is relatively widespread and occurs within some national parks but is susceptible to threats such as climate change and the introduction of exotic species (J. Coughran and J.M. Furse pers. comm. 2009). Climate change poses a threat through increasing temperature, alterations to hydrological regimes and severe weather events (Chiew and McMahon 2002; Howden 2003, Pittock 2003, Hennessy 2006, Westoby and Burgman 2006, IPCC 2007). Euastacus simplex is restricted to very high altitudes, and it is probable that this reflects a requirement for cool conditions.

There is a potential large scale threat from Cane Toads (Rhinella marina) (DEH 2004b) although there are no specific data on impacts for this species. Other exotic introduced species (cats, foxes, pigs, goats) that have generally been found to impact on crayfish (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 2004a,c,d,e) and these exotic species could have localized impacts on this species (J. Coughran and J.M. Furse pers. comm. 2009). 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 (feral pigs, goats, foxes, Cane Toads 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 species-specific conservation measures in place for this species. However its distribution coincides with national parks. Furthermore, in New South Wales, a minimum recreational size limit of 90 mm orbital carapace length (OCL) is in place for any spiny crayfish (NSW DPI 2007). This species does not attain that size, and so is indirectly protected by this restriction (J. Coughran and J.M. Furse pers. comm. 2009).

Further research should be initiated to include population assessment and monitoring, biological and life history information, habitat requirements, investigations into thermal tolerance, population genetics and the impacts of threats occuring within its range (J. Coughran and J.M. Furse pers. comm. 2009).

Citation: Coughran, J. & Furse, J. 2010. Euastacus simplex. The IUCN Red List of Threatened Species 2010: e.T153686A4531912. . Downloaded on 19 September 2018.
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