The Mt Arthur Burrowing Crayfish (Engaeus orramakunna) is a medium-sized burrowing crayfish growing to a length of about 8 cm. The species is among the most terrestrial of the burrowing crayfish in Tasmania. Animals are usually a striking orange in colour but can also be brown. The Mt Arthur Burrowing Crayfish is known from a range of approximately 300 square km centred on Mt. Arthur in north-east Tasmania. The species extends to near Lilydale, Nabowla and South Springfield, and is also found in the vicinity of Launceston. The Mt Arthur Burrowing Crayfish prefers moist seeps and flat swampy or marshy land feeding into or next to streams and rivers, but can also be found in stream banks, wet pasture, culverts and roadside drains. The principal threats to the species are forestry activities and conversion of habitat to pasture.
- Important: Is this species in your area? Do you need a permit? Ensure you’ve covered all the issues by checking the Planning Ahead page.
- Important: Different threatened species may have different requirements. For any activity you are considering, read the Activity Advice pages for background information and important advice about managing around the needs of multiple threatened species.
- 'Habitat’ refers to both known habitat for the species (i.e. in or near habitat where the species has been recorded) and potential habitat (i.e. areas of habitat with appropriate characteristics for the species and within the species potential range which have not yet been adequately surveyed).
- If in doubt about whether a site represents potential habitat for this species, contact the Threatened Species Section for further advice.
- The known range of the Mt Arthur Burrowing Crayfish includes an area of approximately 300 square km centred on Mt. Arthur, north-east Tasmania. The range extends to near Lilydale, Nabowla and South Springfield, and across this range borders on the distributions of four other species of burrowing crayfish: Engaeus tayatea, E. nulloporius, E. mairener and E. leptorhynchus. It is also found in the vicinity of Launceston, although the southern boundary to its distribution remains undefined.
- Note that burrowing crayfish can occur in areas where there has been a lot of human activity, and in places that are not near obvious standing or running water (i.e. they do not need to be in streams or obvious wetlands).
- Habitat for the Mt Arthur Burrowing Crayfish includes the following elements: moist seeps and flat swampy or marshy land feeding into or next to streams and rivers; can also be found in stream banks, wet pasture, culverts and roadside drains.
What to avoid
Clearing and conversion of habitat (e.g. for forestry plantation and agriculture)
Habitat drying out
Trampling of pasture habitat by stock
Crushing crayfish or their burrows
Changes in the water table
- A permit may be required for examination of both living and dead crayfish material.
- Although it is the only burrowing crayfish over most of its range, at the boundaries of its range the Mt Arthur Burrowing Crayfish may overlap with several other Engaeus species: E. mairener, E. nulloporius, E. tayatea and E. leptorhynchus. The Mt Arthur Burrowing Crayfish can be distinguished from all these species by the lack of a transverse suture across the outer parts of the tail fan (uropods). However, identification of specimens should be confirmed using a microscope and a range of features.
- Occasionally dead parts of crayfish such as the carapace (i.e. the outer shell) can be found on the surface of a colony which may be able to be identified by an expert.
- The presence of burrow entrances indicate that the species may be present at a site; often these possess a raised 'chimney' of mud surrounding it (see examples of chimneys). However, definitive identification may require excavation of burrows and identification of actual specimens.
- Note that burrow excavation can be destructive to the animal involved and should only be carried out by a trained specialist with the appropriate permit and the ability to distinguish this species from other burrowing crayfish.
- Burrows of the Mt Arthur Burrowing Crayfish are visible all year and surveys can be carried out year-round. However, survey times should avoid periods of extreme dry or wet weather conditions. Burrows may be hard to spot during very dry periods when there is little activity on the surface, or when conditions are so wet that the chimneys are flooded or washed away.
Helping the species
- In order to recognise the species if it occurs on your property, learn to identify the signs of burrowing crayfish, such as burrow entrances with or without chimneys. If in doubt, seek expert assistance with identification.
- If you live or work in the area where the species occurs (see distribution map, above), look out for and record any observations of the species. All records of this species can provide important information on distribution and abundance.
- If you are interested in knowing for certain whether the species occurs on your land, organise a formal survey. You may need to employ an ecological consultant to do this. Your local Bushcare or Field Naturalist club may be able to assist you with a survey.
- Important! Always report any observations of the species to the NRE Natural Values Atlas, or else provide the data direct to the Threatened Species Section. Records stored on the NVA are a permanent record and are accessible to other people interested in this species.
- Consider the needs of the whole habitat. Preserving a threatened species' habitat is the best way to manage both the species and the environment in which it lives.
- In the areas where the species occurs, consider revegetation and fencing where streamside vegetation is degraded, and to protect waterways from erosion.
- For long-term protection of populations on private land – consider protection of habitat through a vegetation management agreement or conservation covenant. See the NRE Private Land Conservation Program for more details.
Cutting or clearing trees or vegetation
- A major proportion of the distribution of the Mt Arthur Burrowing Crayfish is in State Forest, and the species occurs in areas subject to extensive forestry activity. Over the remainder of its range the species is also impacted by agricultural activity on private land. Clearance and conversion of habitat (e.g. for plantation or agriculture) leads to permanent loss of habitat for this species.
- To avoid permanent habitat loss - do not convert habitat (e.g. to plantation, pasture or cropping land).
- The partial removal of vegetation from a site can also lead to drying out of soil, erosion, sediment input into waterways, and changes in water table levels and drainage.
- To avoid impacts on crayfish populations and their habitat – do not clear trees or other vegetation (e.g. buttongrass vegetation) in areas of burrowing crayfish habitat.
Stock grazing and movement
- Stock can damage burrows and crush crayfish through trampling, and severely degrade burrowing crayfish habitat through the trampling of vegetation and compaction of soil.
- To protect crayfish localities from trampling by stock – fence off habitat.
Use of heavy machinery and vehicles
- Use of heavy machinery (cars, trucks, earth-moving equipment, etc) within burrowing crayfish habitat can crush burrows and crayfish, and lead to severe degradation of habitat through damaging vegetation and compaction of soil.
- To protect crayfish habitat – restrict use of heavy machinery through and within areas of habitat.
- To avoid loss of populations – do not inundate known localities through dam construction.
- Note that a number of activities associated with and following on from the subdivision of a property can lead to the drying out and loss of habitat. Refer to the Activity advice: Subdivision page for background information.
- To prevent drying out of habitat – avoid activities which alter the hydrology in areas of habitat, including removal of native vegetation, earthworks, construction and changes to drainage.
Changing water flow / quality
- Any activity which affects the level of the water table (including planting lots of vegetation at the site) can have impacts on burrowing crayfish habitat. Remember that some activities can effect the level of the water table for a substantial distance around the site of the activity.
- To prevent loss of burrowing crayfish habitat - avoid activities which have an impact on water table levels in areas of burrowing crayfish habitat.
- Activities which result in a major deterioration in water quality can also damage burrowing crayfish habitat.
Activities which can effect water quality include drainage works, earthworks, roading and stock access (all of which can lead to increased sediment reaching waterways), and the entry of chemicals into the waterway (e.g. fertiliser, herbicides and pesticides).
- To avoid impacts on crayfish populations and habitat – ensure weed control operations and the application of fertiliser do not lead to entry of chemicals into burrowing crayfish habitat.
- Activities which result in changes in drainage patterns or waterflow which can damage burrowing crayfish habitat. Activities which can effect drainage patterns and waterflow include roadworks and associated drainage works and removal of vegetation.
- To avoid impacts on crayfish populations and habitat – avoid activities which alter drainage patterns or waterflow in and around areas of habitat.
Check also for listing statement or notesheet pdf above (below the species image).