Cunningham & Milthorpe s.n., 2/8/73
NSW National Parks and Wildlife Service , July 2002
ISBN 0 7313 6517 8
Bertya sp. Cobar-Coolabah is currently only known from four sites in New South Wales: two western and two coastal sites (Figure 2). This includes the earliest recorded site in the Cobar-Coolabah area, as well as the more recently discovered populations in Jacks Creek State Forest (south-west of Narrabri), Gibraltar Range National Park (north-west of Grafton) and Kangaroo River State Forest (north-west of Coffs Harbour).
The original site, on a property near Coolabah, is the only site in far-western NSW where the species is known to still exist, although the population is senescent and not in good health. This population comprises 500-600 plants but there are indications that there were perhaps two to three times this number originally with senescent individuals either dying or being blown-out gradually over the past 20 years (J. Austen pers. comm.). Another population existed on a property approximately 50km further west as recently as 1982, but a decade of continual drought in the area, followed by a large bushfire, may have contributed to the demise of the population (L. Miller pers. comm.).
The largest population of Bertya sp. Cobar-Coolabah occurs at Jacks Creek State Forest, part of the Pilliga forests. The size of this population may be in excess of 5 million plants (J. Austen pers. comm.). There is limited disturbance at the site, other than by apiarists clearing small areas for sites and the construction and maintenance of fire-breaks.
The Gibraltar Range National Park population comprises approximately 20 plants at an advanced age. The Kangaroo River State Forest population comprises about 500 individuals and, like the Gibraltar Range site, plants are situated on cliff edges. It is not known why the species is restricted to these areas, but possibilities are inappropriate fire regimes that have eliminated the species from other areas, and edaphic factors that may have advantaged Bertya sp. Cobar-Coolabah relative to other species which prefer wetter habitats.
|Figure 2. Localities of Bertya sp. Cobar-Coolabah in New South Wales|
There has been no known translocation of Bertya sp. Cobar-Coolabah in NSW nor is any proposed in this Recovery Plan.