White-browed treecreeper (Climacteris affinis) population, in the Carrathool Local Government Area south of the Lachlan River and Griffith Local Government Area - endangered population listing
The Scientific Committee, established by the Threatened Species Conservation Act, has made a Final Determination to list the population of the White-browed Treecreeper Climacteris affinis Blyth, 1864 in Carrathool local government area south of the Lachlan River and Griffith local government area as an ENDANGERED POPULATION in Part 2 of Schedule 1 of the Act. Listing of endangered populations is provided for by Part 2 of the Act.
NSW Scientific Committee - final determination
The Scientific Committee has found that:
1. The White-browed Treecreeper Climacteris affinis Blyth, 1864, is not currently listed as an Endangered Species in Part 1 of Schedule 1 and as a consequence populations of White-browed Treecreeper are eligible for listing on Part 2 of Schedule 1 of the Act.
2. The White-browed Treecreeper is a medium-sized brown and white bird with a white eyebrow and a boldly striped belly. The species forages for insects, primarily ants, on tree trunks and limbs, on fallen logs and on the ground among leaf litter, debris, or on bare ground (Higgins et al. 2001). Treecreepers are basically sedentary once they have undergone post-fledging dispersal. White-browed Treecreepers live as pairs or small groups of birds within permanent territories.
3. White-browed Treecreepers inhabit shrublands and woodlands of arid and semi-arid regions. They mainly occur in tall shrublands and low woodlands dominated by acacias, such as mulga Acacia aneura, gidgee Acacia cambagei, and sheoaks, such as buloke Allocasuarina luehmanni, belah Casuarina cristata and Casuarina pauper; and in woodlands dominated by native pine Callitris spp. Understorey characteristics of occupied habitats vary greatly; vegetation may be open and dominated by grasses; or closed and dominated by a lower layer of low to tall shrubs; the ground-layer may also be bare ground, with no understorey present (Higgins et al. 2001).
4. The population of the White-browed Treecreeper in Carrathool local government area south of the Lachlan River and Griffith local government area lies between the Murrumbidgee and Lachlan Rivers, and forms the south-eastern edge of this species' range. The species was likely to have been widespread in suitable woodland habitat in this area between the lower Murrumbidgee and the Lachlan Valleys. Extensive stands of belah and buloke once occurred between Hillston and Griffith. The species may also have occurred in belts of buloke that occurred in the Hay district.
5. More than 90% of suitable habitat has been cleared in the region and the remaining habitat is mostly in small fragments on farms, roadsides, travelling stock routes and parts of state forests. Since 1990 the population has only been recorded in the Binya State Forest at the southern end of the Cocoparra Range, where the population is estimated to number 20 pairs or less. Any other remaining groups of this population are likely to be isolated and in small numbers given the few remaining areas of suitable habitat in the region and the general paucity of records.
6. Habitat degradation is likely to be a continuing problem for the species. As a ground-foraging species the White-browed Treecreeper is at the same risks of decline and loss for the same reasons as other woodland ground foragers (Freudenberger 1999).
7. There is evidence that unsuitable habitat along the Murrumbidgee and Lachlan Rivers and on the Riverina plains may have isolated this population from other populations over a long period of time. Treecreepers are poor dispersers across fragmented landscapes (Freudenberger 1999) so that exchange of birds between this and other populations has probably been infrequent or non-existent. Consequently, the population in Carrathool local government area south of the Lachlan River and Griffith local government area may be ecologically and genetically distinct from populations to the north and south-west.
8. In addition, the small population size means that there is a major risk of extinction through random population fluctuations, or declines during natural disturbances.
In view of the above the Scientific Committee is of the opinion that the population of the White-browed Treecreeper Climacteris affinis Blyth, 1864 in the Carrathool local government area south of the Lachlan River and Griffith local government area is eligible to be listed as an endangered population because its numbers have been reduced to such a critical level, and its habitat has been so drastically reduced that it is in immediate danger of extinction, and it is not a population of a species already listed in Schedule 1, and it is disjunct and at or near the limit of its geographic range.
Proposed Gazettal date: 06/12/02
Exhibition period: 06/12/02 - 24/01/03
References
Freudenberger, D. (1999).Guidelines for Enhancing Grassy Woodlands for the Vegetation Investment Project. A report commissioned by Greening Australia ACT & SE NSW Inc. (CSIRO Wildlife and Ecology: Canberra.)
Higgins, P. J., Peter, J. M. and Steele, W. K. (Eds). (2001).Handbook of Australian, New Zealand and Antarctic Birds. Volume 5: Tyrant-flycatchers to Chats. (Oxford University Press: Melbourne).