Rufous fieldwren (Calamanthus campestris) - minor amendment determination

The Scientific Committee established by the Threatened Species Conservation Act has made a determination to amend the description of the Striated Fieldwren in Part 1 of Schedule 2 (Vulnerable species) to Calamanthus fuliginosus (Vigors and Horsfield, 1827) sensu stricto and to insert the species Calamanthus campestris (Gould, 1841), Rufous Fieldwren in Part 1 of Schedule 2 of the Act. This determination is made pursuant to Division 5 of Part 2 of the Act.

NSW Scientific Committee - final determination

The Scientific Committee has found that:

1. Calamanthus fuliginosus (Vigors and Horsfield, 1827)  sensu lato is currently listed as a vulnerable species in Schedule 2 of the  Threatened Species Conservation Act, 1995. The Rufous Fieldwren  Calamanthus campestris was recently recognised as a full species separate from the Striated Fieldwren  Calamanthus fuliginosus of coastal south-eastern Australia (Schodde & Mason 1999; Higgins & Peter 2003; Christidis & Boles 2008).

2. The Rufous Fieldwren (family Acanthizidae) is a small (12 cm), scrubwren-like, rusty brown songbird, strongly streaked, with a pale eyebrow, throat and belly, a plain rusty rump, and a cocked tail. It is paler and more rufous than the Striated Fieldwren, and occupies arid rather than coastal habitats. It is similar to the Striated and Thick-billed Grasswrens, but has a different facial pattern and a shorter tail with a white tip. The Rufous Fieldwren can be distinguished from the female Redthroat, which is much plainer, the Shy Heathwren, which has a brighter rufous rump and white wing spot, and the Little Grassbird, which is plainer (less rusty) with a longer, unmarked tail.

3. The Rufous Fieldwren lives on the ground in low, sparse or dense chenopod shrublands, samphire and heathland in arid southern Australia. In NSW it is restricted to the far western arid zone, between the lower Darling River and the South Australian border (Higgins & Peter 2003), existing as a single population contiguous with that in South Australia. It is disjunct from the Victorian population.

4. The size of the population is unknown for NSW, but inferred to be moderately low. Based on the geographic distribution of the Rufous Fieldwren in NSW, which is approximately 5% of that of the Western Australian subspecies C. c.  montanellus, there may be approximately 5000 birds in NSW, assuming bird densities are similar in the two regions (Garnett & Crowley 2000). During the two national bird atlases (Blakers  et al. 1984; Barrett  et al. 2003), the Rufous Fieldwren was recorded in only two grids in the first atlas, and four grids in the second atlas. There were too few NSW records in the two national bird atlases, 1977-81 and 1998-2002, to compare reporting rates in the two time periods (Barrett  et al. 2007). However, these data suggest that the Rufous Fieldwren has a small range and population in NSW.

5. There is little direct evidence of decline in NSW, but declines have been detected in populations elsewhere in the southern Australian sheep-wheat belt. For instance, the species has disappeared from the Fleurieu Peninsula and Adelaide Plains in South Australia, and from parts of the Nullarbor Plain (Higgins & Peter 2003), and it has undergone a “massive reduction” in area of occupancy in the Western Australian wheatbelt in the second half of the 20th century (Garnett & Crowley 2000; Higgins & Peter 2003).

6. The main threat in NSW is degradation of chenopod shrubland habitat through overgrazing by livestock (Higgins & Peter 2003), which can convert saltbush to grassland (Cunningham et al. 1992) and thus remove the fieldwren’s habitat. For instance, the fieldwren’s core range in NSW (the Broken Hill Complex Bioregion) has a landscape stress factor of 4 out of 6 (moderately stressed), based partly on extent and continuity of native vegetation and impact of grazing (Barrett  et al. 2007). About 82% of this area is grazed by livestock, and feral goats are common. Other threats include cultivation of habitat, wildfire, and predation by cats and foxes. ‘Competition and habitat degradation by feral goats,’ ‘Predation by the Feral Cat’ and ‘Predation by the European Red Fox’ are recognised as Key Threatening Processes in NSW under the  Threatened Species Conservation Act 1995.

7. Calamanthus campestris (Gould 1841) is not eligible to be listed as an Endangered or Critically Endangered species.

8. The Rufous Fieldwren Calamanthus campestris (Gould 1841) is eligible to be listed as a Vulnerable species as, in the opinion of the Scientific Committee, it is facing a high risk of extinction in New South Wales in the medium-term future as determined in accordance with the following criteria as prescribed by the  Threatened Species Conservation Regulation 2002:

Clause 16

The estimated total number of mature individuals of the species is:

(c) moderately low,

and:

(d) a projected or continuing decline is observed, estimated or inferred in:

(ii) geographic distribution, habitat quality or diversity, or genetic diversity.

9. The Scientific Committee is of the opinion that the amendment to the description and the insertion of a species in Schedule 2 is necessary or desirable to reflect a reclassification of the species into further species as a result of taxonomic revision. In view of the taxonomic revision, Part 1 of Schedule 2 (Vulnerable species) should be amended to include Calamanthus fuliginosus (Vigors and Horsfield, 1827)  sensu stricto, Striated Fieldwren and to insert the species  Calamanthus campestris (Gould, 1841), Rufous Fieldwren.

Dr Richard Major
Chairperson
Scientific Committee

Proposed Gazettal date: 12/06/09
Exhibition period: 12/06/09 – 07/08/09

References:

Barrett G, Silcocks A, Barry S, Cunningham R, Poulter R (2003) ‘The new atlas of Australian birds.’ (RAOU: Melbourne)

Barrett GW, Silcocks AF, Cunningham R, Oliver DL, Weston MA, Baker J (2007) Comparison of atlas data to determine the conservation status of bird species in New South Wales, with an emphasis on woodland-dependent species. Australian Zoologist 34, 37-77.

Blakers M, Davies SJJF, Reilly PN (1984) ‘The atlas of Australian birds.’ Melbourne University Press: Melbourne)

Christidis L, Boles WE (2008) ‘Systematics and taxonomy of Australian birds.’ (CSIRO: Melbourne)

Cunningham GM, Mulham WE, Milthorpe PL, Leigh JH (1992) ‘Plants of Western New South Wales (3rd edn).’ (Inkata Press: Sydney)

Garnett S, Crowley G (Eds) (2000) ‘The action plan for Australian birds 2000.’ (Environment Australia: Canberra)

Higgins PJ, Peter JM (Eds) (2003) ‘Handbook of Australian, New Zealand and Antarctic birds (Vol. 6).’ (Oxford University Press: Melbourne)

Schodde R, Mason IJ (1999) ‘The directory of Australian birds: Passerines.’ (CSIRO: Melbourne)