Recovery plan for the brush-tailed rock-wallaby - Department of ...

More documents

Recommendations

Info

Approved NSW Recovery Plan Brush-tailed rock-wallaby 38 Figure 10. ESUs and the bioclimatic range of BTRW (NB. ESU boundaries are indicative only.) 9.7.1 Northern ESU There are many BTRW colonies in the Northern ESU and it is estimated that over 90% of BTRWs belong to this group. While there is the possibility of local, short-term extinctions, the Northern ESU populations should be secure in the long-term. There are large tracts of suitable habitat, much of which is in national parks and reserves, particularly in the region from northern Washpool National Park to southern Oxley Wild Rivers National Park. Potential habitat is more fragmented north of Washpool National Park (up to and beyond the NSW–Queensland border), and in the southern part of the ESU towards the Hunter Valley. While there is varying potential for animals to move through the ESU, colonies north of Toowoomba appear to be separated from populations in south-eastern Queensland (Lundie-Jenkins pers. comm.). In a biogeographic context, populations in the Northern ESU occur mainly in the New England Tableland, NSW north coast and south-east Queensland Interim Biogeographic Regionalisation for Australia (IBRA) bioregions. There are also sites in the Nandewar IBRA bioregion. While modelling indicates the bioclimatic core in this northern region occurs north of the Hunter Valley around the Upper Manning River, there is a strong bioclimatic envelope following the ranges as far north as Noosa in south-eastern Queensland (Cavanagh unpub.).
Approved NSW Recovery Plan Brush-tailed rock-wallaby The reasons for the persistence of large populations in this ESU compared to the Southern and Central ESUs is not known, although as noted earlier, lower fox densities and variations in habitat fragmentation may be major factors. However, the highest non-urban fox densities measured to date in Australia were recorded by Thompson and Fleming (1994) in the Northern Tablelands of NSW, who measured 4.6–7.2 foxes/km 2 . The next highest published measurement is for Central Victoria of 3.9 foxes/km 2 by Coman et al (1991). Research into the Northern ESU contingent of BTRWs can provide knowledge about robust populations which can in turn provide important information about recovering the species. However, the robustness of these populations is still in question, as recent work has indicated Northern ESU populations are also in decline. Further surveys and monitoring programs are needed to provide firmer estimates of abundance and connectivity between populations. 9.7.2 Central ESU Most BTRW colonies in the Central ESU appear to be in the northern Blue Mountains national parks (Wollemi and Yengo national parks). The severe decline in the wild colonies around Jenolan Caves, while possibly a local phenomena, indicates that the populations in the southern Blue Mountains are in decline and may be more threatened than those in the north. Knowledge of the occurrence and abundance of BTRWs in the central, less accessible areas of the Greater Blue Mountains national parks is poor, and current estimates may be wrong. However, it is highly unlikely that numbers are greater than 2000, even allowing for error. There are also some sites on which BTRWs have become extinct and one small extant colony between the southern Blue Mountains and Shoalhaven populations, but these are separated by large areas of agricultural land. Populations in the Warrumbungles and Shoalhaven regions now appear to be isolated from the Blue Mountains populations, and the long-term survival of these populations cannot be assured unless active management is undertaken. Suitable BTRW habitat exists south of the Shoalhaven populations, and it is possible that some isolated colonies exist in some of the more remote areas, for example in Deua and Wadbillaga national parks. The small numbers and isolated nature of the Warrumbungles and Shoalhaven populations places them at some risk from inbreeding. This may be a factor in the long-term survival of these populations. On the basis of present knowledge, the Shoalhaven and Warrumbungles populations represent the edges of the range of BTRWs in the Central ESU and are separate from other populations. In this context, conservation of these colonies on-site must be a priority for management. Extant Central ESU populations occur largely in the Sydney Basin. BTRWs are extinct in the South Eastern Highlands and South East Corner IBRA bioregions. The Warrumbungles population is in the Brigalow Belt South IBRA bioregion. The largest bioclimatic core area for the species is in the Greater Blue Mountains, with smaller core areas in the Upper Hunter area, which is separated from the Greater Blue Mountains by the Hunter Valley. There is a general tendency for the core of the bioclimatic range to rise in elevation from south to north, with the greatest topographic range centred on the northern Blue Mountains (Wollemi) (Cavanagh unpub.). Of the two outlying western populations, the Warrumbungles population is in the bioclimatic range associated with the Greater Blue Mountains area, while the Mount Kaputar site is on the edge of the species’ bioclimatic range. 39
Page 1 and 2: Approved Recovery Plan Recovery pla
Page 3 and 4: Contents 1 Introduction ...........
Page 5 and 6: Executive summary The brush-tailed
Page 7 and 8: Approved NSW Recovery Plan Brush-ta
Page 17 and 18: Figure 6. Brush-tailed rock-wallaby
Page 43: Approved NSW Recovery Plan Brush-ta

Recovery plan for the brush-tailed rock-wallaby - Department of ...

You also want an ePaper? Increase the reach of your titles

Delete template?

Save as template?