Euastacus neodiversus 

Scope: Global
Language: English

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Taxonomy [top]

Kingdom Phylum Class Order Family
Animalia Arthropoda Malacostraca Decapoda Parastacidae

Scientific Name: Euastacus neodiversus Riek, 1956

Assessment Information [top]

Red List Category & Criteria: Endangered 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.
Euasatcus neodiversus has been assessed as Endangered under criterion B1ab(iii). This species has an estimated extent of occurrence of 582 km² and has a severely fragmented distribution owing to areas of unsuitable heathland habitat. There is an ongoing decline in the quality of habitat as a result of logging activity which has resulted in sedimentation of this species habitat; studies have shown the negative influence of silt upon this species. This species is also impacted by frequent forest fires of which there have been a number in recent decades. Further work is urgently needed to secure this species habitat through identification of key habitat parameters, and local awareness programs. Further information is needed on the impact that forestry activity is having upon this species is needed to aid decisions on appropriate conservation measures.
Previously published Red List assessments:

Geographic Range [top]

Range Description:

This species is endemic to Australia. It is found on Wilsons Promontory and in the Strzelecki Ranges of southern Victoria at elevations of 50-600 m above sea level (Morgan 1986). The species has a severely fragmented range, with the unsuitable lowland habitat of the Yanakie Isthmus forming a barrier between the Wilson's Promontory population and the remaining mainland sites (Morgan 1986, J. Coughran and J. Furse pers. comm. 2009). Recent surveys of the Strzelecki ranges have failed to locate a single individual of this species (S. Lawler pers. comm. 2008). This species has an extent of occurrence (EOO) of approximately 1,500 km2 (J. Coughran and J. Furse pers. comm. 2009).

Countries occurrence:
Australia (Victoria)
Additional data:
Lower elevation limit (metres):50
Upper elevation limit (metres):600
Range Map:Click here to open the map viewer and explore range.

Population [top]


This species has a restricted, fragmented distribution and is considered to be rare (O'Brien 2007). This species is further regarded to be rare within the Wilson Promentary (S. Lawler pers. comm. 2008). 

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

Habitat and Ecology [top]

Habitat and Ecology:This species is typically found in narrow and shallow waters with a temperature range of 7-15oC and high dissolved oxygen content (Van Praagh 2003). It is more commonly seen in streams with pool habitat and little or no aquatic vegetation (Van Praagh 2003). Riparian vegetation reflects the altitudinal differences of sites within its fragmented range (Morgan 1986, Van Praagh 2003).

Threats [top]

Major Threat(s): A considerable amount of land within the potential range of this species has been converted to pine plantations. However, quantitative studies on the impact of forestry practises on these crayfish are few and far between. Many studies have shown direct effects of timber harvesting on the macro-invertebrates of streams due to decreased water quality and quantity (Campbell and Doeg 1989). Forestry activities may pose direct and indirect threats to this species by changing the flow characteristics of the stream, run-off, the amounts and type of organic debris entering the stream, temperature regimes, and the amount and rate of in-stream sediment (Van Praagh 2003). The deposition of sediment in streams coats the substrata, fills interstitial spaces and is detrimental to young crayfish. These areas are of value in protecting juvenile crayfish from predators. A study recently showed a negative relationship between the presence of this species and levels of instream silt (Koster et al. 1999). Wildfires are another major threat to this species, of which there have been a few in the last decade (S. Lawler pers. comm. 2008).

Although technically protected by recreational fishing regulations, this rare species may be susceptible to over-collection and fishing pressure. Recreational fishing (in particular the taking of large adults) has the capacity to lead to serious and far reaching impacts on population structure (i.e. the stunted population phenomenon (Huner and Lindqvist 1985, Tulonen et al. 2008)), including impairment of reproductive success in females (Tulonen et al. 2008).

Other potential large scale threats that occur within the range of this species, include the threat of predation by exotic fishes such as Brown Trout or Redfin Perch (Davies and McDowall 1996, Rowe et al. 2008). Future potential threats include climate change, particularly with regard to altered hydrological regimes and severe weather events. Climate change modelling predicts that southeastern mainland Australia will experience a warmer and drier climate, leading to decreased run-off and soil moisture (Chiew and McMahon 2002, Howden 2003).

Conservation Actions [top]

Conservation Actions:

This species is listed as Threatened under the Flora and Fauna Guarantee Act 1988 in the state of Victoria. Furthermore, this species range coincides with the Wilson's Promontory National Park. In Victoria, a minimum recreational fishing size of 90 mm Orbital Carpace Length (OCL) applies (DPI 2007); this species does not attain that size, so is indirectly protected by this restriction (J. Coughran and J. Furse pers. comm. 2009).

Future conservation efforts need to focus on describing key habitat parameters for this species and protecting critical habitat. Research should also be initiated into the population status of this species and to what extent impacts such as forestry, invasive species and climate change are having upon it. Research should also be initiated into population genetics of the species and biological and life history information, and investigations into thermal tolerance and resilience to exotic species (J. Coughran and J. Furse pers. comm. 2009). Local awareness programs would benefit this species: at present there is a lack of awareness of this endemic species in this area (S. Lawler pers. comm. 2009).

Citation: Coughran, J. & Furse, J. 2010. Euastacus neodiversus. The IUCN Red List of Threatened Species 2010: e.T8150A12892734. . Downloaded on 21 May 2018.
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