Searching and trapping for Mulgara in the Pilbara

Last week Terrestrial Ecosystems presented at the Department of Parks and Wildlife (DPaW) workshop on Mulgara. This is one a number of workshops being organised by DPaW on Pilbara threatened species.

There was much discussion on which Mulgara species is in WA. The general consensus is that we have Dasycercus blythi, however, there are some historical records of Dasycercus cristicauda. Only with continued sampling from across the state and DNA analysis of tissue samples will we be able to confirm the presence of one or two species.

         D blythi tail       D blythi taiA
Plate 1. Dasycercus sp. tail Plate 2. Dasycercus sp.tail

Terrestrial Ecosystems presentation was motivated by three factors:

  • failure to identify what is actually Mulgara habitat;
  • failure to detect burrows using current techniques;
  • misidentification of burrows in the field; and
  • insufficient trapping effort being used to detect their presence or when trapping and translocating Mulgara.
trap in spini Mulgara Honeymoon Well
Plate 3. Trapping for Mulgara Plate 4. Dasycercus blythi

The presentation went on to describe the outcomes of four case studies completed in the Pilbara. Conclusions from the case studies were that:

  • searching in mature, high or dense spinifex and low shrubs resulted in many burrows not being detected;
  • it was relatively easy to misidentify burrows used by Mulgara;
  • mulgara passed multiple baited traps on multiple nights before they were caught;
  • in a high density population of Mulgara, a minimum of 200 trap-nights/individual were necessary to capture most Mulgara; and
  • five nights of trapping was insufficient to catch all Mulgara in an area when traps were placed at 25m centres.
before fire after fire
Plate 5. Mulgara habitat before fire Plate 6. Mulgara habitat after fire

Terrestrial Ecosystems recommended that:

  • assuming that Mulgara are living in burrows, searches to record the presence of Mulgara in an area should only occur when:
    • the height of spinifex or shrubs is less than 500mm;
    • the vegetation cover is less than 40%; and
    • the search effort is greater than two persons/ha/hr.
  • in areas where the height of spinifex and shrubs is greater than 500mm and the vegetation cover is greater 40%, then the area should be trapped instead of grid searched;
  • the minimum trapping effort to detect or remove all Mulgara from an area should be 16 traps/ha (25m centres) with traps set for a minimum of 7 nights; and
  • when the purpose of the trapping program is to catch all/or record all Mulgara in an area, trapping should cease when no Mulgara have been caught within 400mm of the trap for three consecutive nights.

All copy of the presentation can be downloaded here. These data are currently in review for scientific publication.

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