Strategic Management Prospects v4.0 Species Forecast Report created on 18 July, 2024

A Species Forecast Report is a summary of currently available information, the predicted 50-year outlook for the species, and potential pathways to recovery through species-specific and landscape-scale actions.

The report collates data from a range of sources including the Victorian Biodiversity Atlas, Strategic Management Prospects (SMP), Specific Needs Assessments, Threatened Species Action Statements, the Genetic Risk Index, and the IUCN Common Assessment Method.

Species Forecast Reports are intended to be used in conjunction with SMP and other spatial outputs in NatureKit, and Action Statements where relevant.

For more information on Species Forecast Reports, SMP and other biodiversity decision support tools, including user guides, visit Choosing actions for nature webpage on the DEECA website.


Species Overview

Taxon ID 1693
Scientific name Engaeus sternalis
Common name Warragul Burrowing Crayfish
Group Mussels, decapod crustacea
FFG status Critically Endangered
EPBC status
Warragul Burrowing Crayfish (Image Source: Heather Stacy )

Warragul Burrowing Crayfish (Image Source: Heather Stacy )


Species description

Description and life history

The Warragul Burrowing Crayfish is a small burrowing crayfish, with adults having a carapace length of about 20 mm and a total length of about 70 mm (Horwitz 1990). The taxon is characterised by its very small eyes and fine downy hairs covering its carapace. It is usually a pale, cream colour but may also present in shades of blue and grey. It builds small chimneys, composed of small, spherical balls of soil with small entrances. Several adults and young have been found in the same burrow system. While the specific life-cycle of the Warragul Burrowing Crayfish is unknown, in most burrowing crayfish, breeding occurs over spring and summer (Doran 1999).

Distribution

The taxon was originally described in 1886 but no precise locality data was given. The description of this “lectotype” corresponds with that of E. sternalis given by Clark (1936) for a specimen that was found in “Warragul”. Up until 1995, this taxon was only known from one locality at Wattle Creek, a tributary of Labertouche Creek, just north of Old Telegraph Rd, Labertouche (Horwitz 1990, Morey and Hollis 1997). Surveys by Shaw (1996) extended the known range of this taxon to include sections of the Labertouche Creek within the Janet Clarke Reserve and a site further downstream near the junction with the Tarago River. Morey and Hollis (1997) collected three Warragul Burrowing Crayfish using pitfall traps in grazing land adjacent to Labertouche Creek, 50 m downstream from the 1983 site of Horwitz. However, extensive searches around Warragul and surrounding areas failed to locate the taxon outside the Labertouche Creek area (Horwitz 1990, Morey and Hollis, 1997, Shaw 1996 and Van Praagh and Hinkley 1999, Van Praagh 2010). This has led to the supposition that either the original “Warragul” locality referred to the Labertouche area or that the taxon had become extinct from the Warragul region. However, during fauna surveys in October 2010, Warragul Burrowing Crayfish were located along a drainage line in a cleared paddock at Warragul (Van Praagh 2010). Surveys in the past possibly relied on the thought that this taxon did not build chimneys surrounding the entrances to their burrows making them extremely difficult to survey. The identification of distinctive chimneys belonging to this taxon (Van Praagh 2011) along with an increased survey effort has increased the known range of this taxon. Further surveys since this time have found the crayfish in pasture around wetlands in Drouin and Warragul. While the new locality records represent a range expansion from its previously thought range, the threatening processes operating within the Drouin and Warragul region, particularly in relation to urban expansion are much higher than those at Labertouche where a proportion of the taxon’s habitat is afforded some protection within the Janet Clarke Flora and Fauna Reserve. There is a gap north-west of Drouin to Longwarry and Labertouche but it is unclear whether this reflects lack of survey effort rather than a true absence of the taxon. In addition to the Labertouche creek system, the taxon has been recorded from creeks and drainage lines in the Hazel and Spring Creek catchments of Warragul and Gum Scrub Creek and King Parrot Creek in Drouin.

Habitat

The taxon’s habitat at Labertouche is remnant Swampy Woodland where the taxon occurs within the clay creek banks. Remnant patches of indigenous vegetation, some of which is in a relatively natural condition, and scattered eucalypts (Eucalyptus viminalis and E. ovata) are present along these creeks (Morey 1999). This contrasts with the taxon’s habitat in Warragul and Drouin where it is found in clay soils within open pasture along edges of creek banks, drainage lines and within floodplains. The crayfish can be found some distance from open waterways. It tends to be found in the less saturated areas of flood zones.

Genetic Risk Index

This table contains information on the genetic health of Warragul Burrowing Crayfish, informed by recent work conducted by Monash University and cesar Pty Ltd (Kriesner et al. 2019; Kriesner and Weeks 2020). The project undertook genetic risk assessments of ~1,100 species of flora and fauna found in Victoria and generated a large database of available genetic and demographic data for these species. A framework was developed for combining these parameters into a Genetic Risk Index that classified species broadly into ‘Low’, ‘Moderate’, ‘High’, ‘Very High’ and ‘Uncertain’ risk categories. The Genetic Risk Index will continue to undergo refinement and validation to provide further insight into the genetic health of species in Victoria.

Total Australian population size 50 - 500 individuals
Australian distribution Only occurs in Victoria
Dispersal capacity Very low: ~320m
Reproductive mode Sexual: species reproduces sexually via male and female gametes
Average generation time One generation every 2 - 5 years
Victorian population trend since ~1975 Population has moderately decreased
Inbreeding evidence Not assessed
Genetic diversity Not assessed
Genetic rescue potential Uncertain
Genetic Risk Index Very high


Species maps

Habitat Distribution Model

The Habitat Distribution Model (HDM) layer shows the modelled distribution of habitat for Warragul Burrowing Crayfish in Victoria. Red shading indicates areas of habitat with relatively higher suitability, compared with yellow shaded areas. HDMs are developed by combining Victorian Biodiversity Atlas (VBA) occurrence records for the species with a range of environmental variables to predict where the most suitable habitat for the species is in Victoria. Species may not always occupy areas of suitable habitat. Threatening processes (prior or ongoing) and disturbance regimes (e.g. fire, timber harvesting) may stop species from occupying otherwise suitable habitat for periods of time. Management actions often focus on currently occupied areas, however management of unoccupied areas can also be important to allow populations to re-establish.

No Habitat Distrabution Model is currently available.


Species Forecast

No Species Forecast data is available because Warragul Burrowing Crayfish is not yet included in our decision-support tools.

About Species Forecast

A Species Forecast is the estimated likelihood of a species being present in 50 years time. The data for Species Forecasts is drawn from DEECA’s decision support tools, Strategic Management Prospects and Specific Needs Assessments.

Many species benefit from the management of widespread threats, such as weeds and pests, and the benefit of these landscape-scale actions to ~4,200 species is modelled in Strategic Management Prospects. In addition to landscape-scale actions, some species also need actions that improve or protect habitat at certain sites, such as nest boxes or hollow logs, or actions to improve certain populations, such as gene mixing or translocation.

As part of a continuous improvement program for our decision-support tools, we are working to expand the scope of actions modelled in Strategic Management Prospects, and to build the dataset of species benefits from location-specific and population-specific actions.

We can use this data to consider how different actions may benefit a species and examine how different types of on-ground management may contribute to a species’ recovery in 50 years, to develop a Species Forecast.


Potential actions for species recovery

No Species Forecast data is available because Warragul Burrowing Crayfish is not yet included in our decision-support tools.


Species prospects in SMP

The benefit data in SMP can be used to consider what the Warragul Burrowing Crayfish’s prospects are if the landscape scale management actions in SMP are implemented.

No Species Prospects figure is available becuase Warragul Burrowing Crayfish is not yet included in SMP.


How to get further information and provide feedback

For more information on the decision support tools, products and underlying data used in this report, and how the data is collected and developed into products, please visit the following links:

These links include information on how to provide data and feedback into these products.

The Species Forecast Reports will be updated periodically to reflect changes and improvements in the products and tools that inform them (e.g., following updates to SMP).

As the data contained in Species Forecast Reports is drawn from multi-species datasets, it is not currently possible to incorporate species-specific information or feedback directly.

For help or further information get in touch by visiting Choosing actions for nature webpage on the DEECA website.


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