Engaeus australis

Taxonomy

Assessment Information

Geographic Range

Population

Habitat and Ecology

Threats

Conservation Actions

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Taxonomy [top]

Kingdom	Phylum	Class	Order	Family
ANIMALIA	ARTHROPODA	CRUSTACEA	DECAPODA	PARASTACIDAE

Scientific Name:

Engaeus australis

Species Authority:

Riek, 1969

Common Name/s:

English

–

Lilly Pilly Burrowing Crayfish

Assessment Information [top]

Red List Category & Criteria:

Near Threatened ver 3.1

Year Published:

2010

Assessor/s:

Doran, N. & Horwitz, P.

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:
Engaeus australis has been assessed as Near Threatened. While this species has an extent of occurrence (EOO) of approximately 500 km² and a severely fragmented distribution, there is no evidence that this species is undergoing a decline in population numbers or quality of habitat at the present time. Much of this species range is also contained within national parkland, thereby affording it indirect protection from development and land-use change. Further research and monitoring of the population trends, threats and distribution of this species is needed as it is sensitive to climatic changes such as increased droughts, and forest fires.

History:

1996	–	Endangered
1994	–	Rare (Groombridge 1994)

Geographic Range [top]

Range Description:	This species is endemic to Australia, and has only been found on Wilsons Promontory, Southern Victoria. Due to the low disperal ability expected for this species, and the isolation of the Promontory from both the mainland of Victoria (by the Yanakie Isthmus) and the Bass Strait Islands including Tasmania, it is unlikely that the species will be found elsewhere (Horwitz 1990). The area in which this species is distributed is 517 km², and this species is thought to have a severely fragmented distribution (P. Horwitz pers. comm. 2009).
Countries:	Native: Australia (Victoria)
Range Map:	Click here to open the map viewer and explore range.

Population [top]

Population:	There are insufficient population data available for this species.
Population Trend:	Unknown

Habitat and Ecology [top]

Habitat and Ecology:	The burrows of this species are usually located on the hill slopes adjacent to the flood plain where they receive no water from the water-table (type 3 burrows). The soil consists of 1 - 2 cm of macro-organic material, followed by 15 - 40 cm of silty sand and a gradual change to soils with a heavier component of clay. The largest individual found has a carapace length of 26.8 mm, and the largest reproductive female was 24.1 mm carapace length (Horwitz 1990).
Systems:	Freshwater

Habitat and Ecology:

The burrows of this species are usually located on the hill slopes adjacent to the flood plain where they receive no water from the water-table (type 3 burrows). The soil consists of 1 - 2 cm of macro-organic material, followed by 15 - 40 cm of silty sand and a gradual change to soils with a heavier component of clay. The largest individual found has a carapace length of 26.8 mm, and the largest reproductive female was 24.1 mm carapace length (Horwitz 1990).

Systems:

Freshwater

Threats [top]

Major Threat(s):	The only known major threat to this species is its restricted distribution to one small region which falls within a gazette national park (P. Horwitz pers. comm. 2009). Regional disturbance such as a decline in rainfall and repetitive severe fires could cause significant declines in subpopulations (P. Horwitz pers. comm. 2009). Fire hasn't been a major issue for burrowing crayfish in the past as they are insulated by the soil; however fire frequency and severity have been increasing under climate change, while habitats have been drying out (N. Doran pers. comm. 2009). Furthermore, species living in type 3 burrows might be exceptionally susceptible to climate change as they rely on predictable level and timing of water supply (N. Doran pers. comm. 2009).

Major Threat(s):

The only known major threat to this species is its restricted distribution to one small region which falls within a gazette national park (P. Horwitz pers. comm. 2009). Regional disturbance such as a decline in rainfall and repetitive severe fires could cause significant declines in subpopulations (P. Horwitz pers. comm. 2009). Fire hasn't been a major issue for burrowing crayfish in the past as they are insulated by the soil; however fire frequency and severity have been increasing under climate change, while habitats have been drying out (N. Doran pers. comm. 2009). Furthermore, species living in type 3 burrows might be exceptionally susceptible to climate change as they rely on predictable level and timing of water supply (N. Doran pers. comm. 2009).

Conservation Actions [top]

Conservation Actions:	There are no species-specific conservation measures in place for this species. However, part of its range coincides with national parkland. It has not been listed for protection under any State or Federal Acts (P. Horwitz pers. comm. 2009). A regional survey of this species range is required (P. Horwitz pers. comm. 2009). Future research should focus on establishing a broad scale audit (population trends, distribution and threats) and monitoring program across this genus and other burrowing crayfish as they are likely to be very sensitive indicators of habitat and climate change (N. Doran pers. comm. 2009).

Conservation Actions:

There are no species-specific conservation measures in place for this species. However, part of its range coincides with national parkland. It has not been listed for protection under any State or Federal Acts (P. Horwitz pers. comm. 2009). A regional survey of this species range is required (P. Horwitz pers. comm. 2009). Future research should focus on establishing a broad scale audit (population trends, distribution and threats) and monitoring program across this genus and other burrowing crayfish as they are likely to be very sensitive indicators of habitat and climate change (N. Doran pers. comm. 2009).

Citation:	Doran, N. & Horwitz, P. 2010. Engaeus australis. In: IUCN 2012. IUCN Red List of Threatened Species. Version 2012.2. <www.iucnredlist.org>. Downloaded on 19 June 2013.
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