Biodiversity

Species Profile and Threats Database


For information to assist proponents in referral, environmental assessments and compliance issues, refer to the Policy Statements and Guidelines (where available), the Conservation Advice (where available) or the Listing Advice (where available).
 
In addition, proponents and land managers should refer to the Recovery Plan (where available) or the Conservation Advice (where available) for recovery, mitigation and conservation information.

EPBC Act Listing Status Listed as Vulnerable
Listing and Conservation Advices Commonwealth Listing Advice on Engaeus orramakunna (Mt Arthur Burrowing Crayfish) (Threatened Species Scientific Committee (TSSC), 2001af) [Listing Advice].
 
Recovery Plan Decision Recovery Plan required, this species had a recovery plan in force at the time the legislation provided for the Minister to decide whether or not to have a recovery plan (19/2/2007).
 
Adopted/Made Recovery Plans Burrowing Crayfish (Engaeus) Group Recovery Plan 2001-2005 (Doran, N., 1999b) [Recovery Plan].
 
Policy Statements and Guidelines Draft referral guidelines for four threatened Tasmanian burrowing crayfish (Department of Sustainability, Environment, Water, Population and Communities (DSEWPaC), 2011s) [Admin Guideline].
 
Federal Register of
    Legislative Instruments
Inclusion of species in the list of threatened species under section 178 of the Environment Protection and Biodiversity Conservation Act 1999 (14/07/2001) (Commonwealth of Australia, 2001g) [Legislative Instrument].
 
State Government
    Documents and Websites
TAS:Tasmania's Freshwater Burrowing Crayfish (Department of Primary Industries and Water (DPIW), 2007) [Information Sheet].
TAS:Engaeus orramakunna (Mount Arthur Burrowing Crayfish): Species Management Profile for Tasmania's Threatened Species Link (Threatened Species Section (TSS), 2014vb) [State Action Plan].
State Listing Status
TAS: Listed as Vulnerable (Threatened Species Protection Act 1995 (Tasmania): September 2012 list)
Non-statutory Listing Status
IUCN: Listed as Near Threatened (Global Status: IUCN Red List of Threatened Species: 2013.1 list)
Scientific name Engaeus orramakunna [66778]
Family Parastacidae:Decapoda:Malacostraca:Arthropoda:Animalia
Species author Horwitz, 1990
Infraspecies author  
Reference ANZECC Threatened Fauna List May 2000
Distribution map Species Distribution Map

This is an indicative distribution map of the present distribution of the species based on best available knowledge. See map caveat for more information.

Illustrations Google Images
http://www.crayfishworld.com/engaeus-tas3.htm

Scientific name: Engaeus orramakunna

Common name: Mount Arthur Burrowing Crayfish

The Mount Arthur Burrowing Crayfish grows to 8 cm long. It is orange in colour and is paler on its underside and darker on its back. Younger animals may vary from dark reddish-brown to translucent grey-blue in colour (Bryant & Jackson 1999b). The species has long antenna which extend well beyond the edge of the carapace (LEC 2003).

The Mount Arthur Burrowing Crayfish is known from a range of 300 km² centred on Mount Arthur in north-east Tasmania. Its occupancy within its range is not well known, however, suitable habitat is common. The species extends to near Lilydale, Nabowla and south Springfield. Its range borders on distributions of other freshwater crayfish, including Engaeus tayatea, E. nulloporius, E. mairener and E. leptorhynchus. The species is also found near Launceston, although its exact boundary remains undefined. The north-east extreme of its distribution extends into an area of significant biological diversity and evolutionary importance for burrowing crayfish and Tasmanian fauna as a whole (Horwitz 1996, cited in Doran 1999b). Approximately 55% of the species' northern distribution occurs in state forests. A comprehensive review of the species distribution can be found in Doran and Richards (1996).

The number of adult individuals is estimated to be 1 400 000 to 4 000 000. Since European settlement the species is considered to have undergone a substantial reduction in numbers (60–66%) due to human disturbance (TSSC 2001af).

The Mount Arthur Burrowing Crayfish has been found in high abundance in a range of habitats. These include undisturbed rainforests, eucalypt forest, open pasture, cattle trampled pasture and roadside gutters. The primary habitat requirement appears to be a high level of moisture combined with soil suitable for burrowing.

There is no uniform distribution of burrows throughout the species' habitat. In some sites burrows are uniformly distributed, while in others they are patchy (Doran & Richards 1996). Burrows are found in steep sided banks, steep stream slopes and flat marshy seeps and pans. Burrows are commonly found in areas with high canopy cover, high ground cover or low canopy cover and low ground cover and all combinations of these sites. Burrows are recorded in both open and closed habitat. Despite the ad hoc distribution and habitat or burrow location, all active burrows were found in sites of high soil moisture and high clay content (DPIW 2007b). The species occupies burrow types connected to the water table and types independent of the water table, which are dependant on surface runoff (Horwitz & Richardson 1986). In the southern regions of the species' range the soil character changes, becoming darker topsoils with an underlying reddy-grey clay (Doran & Richards 1996).

Burrows are usually found in the presence of ferns such as Dicksonia antarctica. They are also found under a range of canopy species, including eucalypt, tea-tree, paperbarks, Radiata Pine (Pinus radiata) and Sassafras (Atherosperma moschatum) (Doran & Richards 1996). A comprehensive review of the species' habitat can be found in Doran and Richards (1996).

Burrowing crayfish live their entire lives within burrow systems, only emerging occasionally at night and in damp, overcast conditions. All burrowing crayfish have gills under the carapace, making them dependent on water to breathe (DPIW 2007).

The Mount Arthur Burrowing Crayfish is believed to begin breeding in late May. Females of the species have been found carrying undifferentiated eggs in mid-June, early August, late October and early November. Males have been observed occupying the same burrow as females throughout these periods (Doran 1999b).

Distinctiveness
The Engaeus genus, which includes the Mount Arthur Burrowing Crayfish, can be distinguished from other freshwater crayfish on the basis of size (Engaeus species are very small); claw orientation and shape; carapace (shield covering the back) grooves; and the location and number of spines on the body (DPIW 2007; Horwitz 1988).

Survey methods
The following survey methods were developed during a workshop in June 2010 are recommended for presence/absence surveys (Tasmanian Burrowing Crayfish Workshop 2010). Where it is not possible to conduct surveys in this manner, failure to detect burrowing crayfish should not be considered indicative of their absence.

Surveys should:

  • maximise the chance of detecting the species
  • determine the context of the site within the broader landscape
  • account for uncertainty and error (such as false presences and absences)
  • be conducted by a suitably qualified person with experience in burrowing crayfish surveys, or in consultation with burrowing crayfish experts.

Visual search
The first step in surveying for burrowing crayfish is a visual search to locate burrows within suitable habitat. Presence of burrows in suitable habitat indicates the presence of burrowing crayfish. The recommended minimum search effort is one hour per hectare (Tasmanian Burrowing Crayfish Workshop 2010).

Species identification
In areas where only one burrowing crayfish species occurs, the presence of crayfish burrows confirms the presence of that species. However, in some areas, more than one crayfish species may be present (that is, the species occur together). In an area of overlapping distributions, further investigation is needed once burrows have been located to determine the species occupying a particular microhabitat. This will usually involve burrow excavation. Burrow excavation surveys must be designed and implemented in a way that minimises the disturbance to habitat at the site and should only be conducted in consultation with burrowing crayfish experts. During survey work, appropriate protocols for hygiene controls should be maintained to avoid the spread of pathogens such as chytrid fungus and Phytophthora into crayfish habitat. Permits may be needed for burrow excavation surveys (Tasmanian Burrowing Crayfish Workshop 2010).

Across its range, the Mount Arthur Burrowing Crayfish is subject to pressures from forestry and agricultural activities (Doran 1999b).

The Mount Arthur Burrowing Crayfish is sensitive to changes in water quality, such as pollutants introduced by human activities. However, siltation does not seem to pose a threat to this species (Doran & Richards 1996). Trampling by cattle is a direct threat to crayfish during the mating period of late spring and early summer when they are close to or on the surface. In areas where cattle are present, the Mount Arthur Burrowing Crayfish generally seems tolerant of mild soil trampling, although heavy cattle activity may be detrimental (Doran & Richards 1996).

The Burrowing Crayfish Group Recovery Plan 2001-2005 (Doran 1999b) was developed to stabilise and improve the conservation status of the species. Specific objectives included the improvement of habitat protection for the species, an increase in public awareness and involvement in threatened species protection and to ensure the species long-term survival throughout its area of occupancy. To achieve this, the following recovery actions were recommended:

  • habitat assessment
  • improvement of reservation status for the species
  • habitat management within agricultural areas
  • habitat management within forestry and commercial harvesting areas
  • habitat management within urban and other areas
  • community involvement and education
  • population and habitat monitoring.

The following table lists known and perceived threats to this species. Threats are based on the International Union for Conservation of Nature and Natural Resources (IUCN) threat classification version 1.1.

Threat Class Threatening Species References
Agriculture and Aquaculture:Agriculture and Aquaculture:Fertiliser application Burrowing Crayfish (Engaeus) Group Recovery Plan 2001-2005 (Doran, N., 1999b) [Recovery Plan].
Agriculture and Aquaculture:Agriculture and Aquaculture:Land clearing, habitat fragmentation and/or habitat degradation Burrowing Crayfish (Engaeus) Group Recovery Plan 2001-2005 (Doran, N., 1999b) [Recovery Plan].
Agriculture and Aquaculture:Livestock Farming and Grazing:Grazing pressures and associated habitat changes Burrowing Crayfish (Engaeus) Group Recovery Plan 2001-2005 (Doran, N., 1999b) [Recovery Plan].
Agriculture and Aquaculture:Livestock Farming and Grazing:Habitat loss and modification due to clearance of native vegetation and pasture improvements Burrowing Crayfish (Engaeus) Group Recovery Plan 2001-2005 (Doran, N., 1999b) [Recovery Plan].
Biological Resource Use:Logging and Wood Harvesting:Habitat disturbance due to foresty activities Burrowing Crayfish (Engaeus) Group Recovery Plan 2001-2005 (Doran, N., 1999b) [Recovery Plan].
Invasive and Other Problematic Species and Genes:Problematic Native Species:Competition, grazing, predation and/or habitat degradation by rats Burrowing Crayfish (Engaeus) Group Recovery Plan 2001-2005 (Doran, N., 1999b) [Recovery Plan].
Natural System Modifications:Dams and Water Management/Use:Alteration of hydrological regimes and water quality Burrowing Crayfish (Engaeus) Group Recovery Plan 2001-2005 (Doran, N., 1999b) [Recovery Plan].
Natural System Modifications:Dams and Water Management/Use:Changes in hydrology including habitat drainage Burrowing Crayfish (Engaeus) Group Recovery Plan 2001-2005 (Doran, N., 1999b) [Recovery Plan].
Natural System Modifications:Dams and Water Management/Use:Changes to hydrology including construction of dams/barriers Burrowing Crayfish (Engaeus) Group Recovery Plan 2001-2005 (Doran, N., 1999b) [Recovery Plan].
Natural System Modifications:Fire and Fire Suppression:Inappropriate and/or changed fire regimes (frequency, timing, intensity) Burrowing Crayfish (Engaeus) Group Recovery Plan 2001-2005 (Doran, N., 1999b) [Recovery Plan].
Natural System Modifications:Fire and Fire Suppression:Inappropriate prescribed regimes and/or vegetation management to control fire regimes Burrowing Crayfish (Engaeus) Group Recovery Plan 2001-2005 (Doran, N., 1999b) [Recovery Plan].
Pollution:Agricultural Effluents:Environmental impacts due to application of fertilisers, herbicides and pesticides Burrowing Crayfish (Engaeus) Group Recovery Plan 2001-2005 (Doran, N., 1999b) [Recovery Plan].
Pollution:Agricultural Effluents:Pesticide application Burrowing Crayfish (Engaeus) Group Recovery Plan 2001-2005 (Doran, N., 1999b) [Recovery Plan].

Bryant, S. & J. Jackson (1999b). Tasmania's Threatened Fauna Handbook: What, Where and How to Protect Tasmania's Threatened Animals. Hobart, Tasmania: Threatened Species Unit, Parks and Wildlife Service.

Department of Primary Industries and Water (DPIW) (2007). Tasmania's Freshwater Burrowing Crayfish. [Online]. Hobart, Tasmania: DPIW. Available from: http://www.dpiw.tas.gov.au/inter.nsf/WebPages/LJEM-73J92W?open.

Department of Primary Industries and Water (DPIW) (2007b). Habitat preferences and water requirements of the Mt. Arthur burrowing crayfish (Engaeus orramakunna) and the Scottsdale burrowing crayfish (Engaeus spinicaudatus). Tasmania: Water Resources Division, DPIW.

Doran, N. (1999b). Burrowing Crayfish (Engaeus) Group Recovery Plan 2001-2005. [Online]. Tasmania: Parks and Wildlife Service, Department of Primary Industries, Water and Environment. Available from: http://www.environment.gov.au/biodiversity/threatened/publications/recovery/burrowing-crayfish/index.html.

Doran, N. & K. Richards (1996). Management requirements for rare and threatened burrowing crayfish in Tasmania. In: Report to the Tasmanian RFA Environment and Heritage Technical Committee. [Online]. Hobart: Tasmanian Public Land Use Commission, Forestry Tasmania. Available from: http://www.daff.gov.au/rfa/regions/tasmania/environment/crayfish.

Horwitz, P. (1988). A key to the genera of Tasmanian freshwater crayfish. The Tasmanian Naturalist. 94:1-3.

Horwitz, P. & A. Richardson (1986). An Ecological Classification of the Burrows of Australian Freshwater Crayfish. Australian Journal of Marine Freshwater Research. 37:237-242.

International Union for Conservation of Nature (IUCN) (2010). IUCN Red List of Threatened Species. Version 2010.4. [Online]. Available from: http://www.iucnredlist.org.

Launceston Environment Centre (LEC) (2003). Tasmania's Freshwater Burrowing Crayfish (Engaeus sp.) and the Mainland Yabby. [Online]. Launceston, Tasmania: LEC. Available from: http://www.lec.org.au/engaeus/resources/4/yabby%20notesheet.pdf.

Tasmanian Crayfish Workshop (2010). Proceedings of the Tasmanian Crayfish Workshop, 28-29 June 2010. Devonport, Tasmania.

Threatened Species Scientific Committee (TSSC) (2001af). Commonwealth Listing Advice on Engaeus orramakunna (Mt Arthur Burrowing Crayfish). [Online]. Available from: http://www.environment.gov.au/biodiversity/threatened/species/e-orramakunna.html.

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This database is designed to provide statutory, biological and ecological information on species and ecological communities, migratory species, marine species, and species and species products subject to international trade and commercial use protected under the Environment Protection and Biodiversity Conservation Act 1999 (the EPBC Act). It has been compiled from a range of sources including listing advice, recovery plans, published literature and individual experts. While reasonable efforts have been made to ensure the accuracy of the information, no guarantee is given, nor responsibility taken, by the Commonwealth for its accuracy, currency or completeness. The Commonwealth does not accept any responsibility for any loss or damage that may be occasioned directly or indirectly through the use of, or reliance on, the information contained in this database. The information contained in this database does not necessarily represent the views of the Commonwealth. This database is not intended to be a complete source of information on the matters it deals with. Individuals and organisations should consider all the available information, including that available from other sources, in deciding whether there is a need to make a referral or apply for a permit or exemption under the EPBC Act.

Citation: Department of the Environment (2014). Engaeus orramakunna in Species Profile and Threats Database, Department of the Environment, Canberra. Available from: http://www.environment.gov.au/sprat. Accessed Fri, 19 Sep 2014 03:49:14 +1000.