Threatened Species Unit, North East Branch
New South Wales Department of Environment and Conservation, 2004
ISBN: 174122 135 8
- 3.1 Collection history and geographical distribution
- 3.2 Population size
- 3.3 Tenure
- 3.4 Genetic variability
- 3.5 Significant habitat
- 3.6 Critical habitat
Grevillea beadleana is known from four disjunct localities in northern NSW (Figure 2). The majority of plants are found in the Binghi region to the north of Torrington and west of the New England Highway. In this area, there are a number of separate populations over an area of about 30 km2, with an estimated total of about 40 000 plants. The next largest population is located on the tablelands above the Macleay gorges escarpment near Enmore, 25 kms south-east of Armidale, in and adjacent to the Oxley Wild Rivers National Park. In Guy Fawkes River National Park, 30 kms north of Ebor, there are two populations, separated by about 20 kms and totalling 700 plants. The other population, consisting of only four plants, is located at Chambigne Nature Reserve 30 kms south-west of Grafton on an escarpment in the Orara River catchment. G. beadleana was previously known last century from near Walcha, however, despite searches, it has not been relocated in this area.
Grevillea beadleana was first collected in 1887 at Walcha (McGillivray 1993). The specimen from this collection has not been viewed in the preparation of the Recovery Plan, but it is apparently housed in the National Herbarium of Victoria (McGillivray 1993). The species has not been found again in the Walcha district despite searches for it in the early 1980s (J.B. Williams pers. comm.) and systematic searches more recently (P. Davies & P. Metcalfe pers. comm.).
In 1981 a Grevillea beadleana specimen was collected from the Guy Fawkes River National Park (N. Fenton pers. comm.). The type material was collected in June 1982 and was brought to the attention of the National Herbarium of NSW. It recognised that the species was allied to the specimen collected from Walcha and in 1986 it formally described as G. beadleana.
In 1988 a new population was discovered 15 kms north of Torrington and about 40 kms south of the Queensland border (Figure 2). The very extensive occurrence of Grevillea beadleana is referred to in this document as the Binghi population, although it is recognised that gene flow within the greater area may not be continuous.
In 1994, a small population was discovered 30 kms south-west of Grafton on land which has since become Chambigne Nature Reserve. In 1998 another small population was discovered in a recent western addition to the Guy Fawkes River National Park. In November 1999, a population of over 2 000 plants was located near Enmore south-east of Armidale.
The reasons for Grevillea Beadleanas rarity are largely unknown. It is likely that the populations within Guy Fawkes River National Park and Chambigne Nature Reserve were more extensive but have declined into refugia because of too frequent fires. Anecdotal information also suggests that the species, locally known as the bottle-brush from the river banks, was common in the Torrington district 40 years ago but declined due to grazing pressures (S. Caldwell pers. comm.).
The first population census of the species was undertaken in 1989 at the eastern population within the Guy Fawkes River National Park (M. Dwyer pers. comm.). The site was traversed and it was estimated that 714 living plants were present in an area of about
4.25 hectares. Part of this population was surveyed in 1991 with 266 live plants being recorded in an area of three hectares (Benson 1991).
In August 1995, after a very intense fire in October 1994, 651 plants were counted, including 84 dead adults and only 62 reproductive adults, in an area roughly corresponding to the 1989 survey (Streat 1997). In March 1996 a further two adult plants had died and about 20% of the mature plants were coppicing (Gross unpublished data). At a new site near the Aberfoyle River, located in March 2000, it was estimated that 150 plants were present, with approximately 30 seedlings, 50 immature and 70 mature plants.
In 1991 the Binghi population was estimated at 4 000 plants over 20 hectares in two discrete groups: 5 hectares at the Knoll and 15 hectares at Oaky Creek (Benson 1991). In 1996, based on transect counts and ground truthing, the population at the same two areas was estimated at 40 000 plants in 270 hectares and a corridor of plants was found linking the two areas (Streat 1997).
At the Chambigne Nature Reserve seven adult plants and two seedlings were found in 1994 (P. Sheringham pers. comm.). Only six of these plants were found again in both 1995 and in 1996. In 2000 nine plants were found (A. Steed pers. comm.) over a larger area than previously known.
A full census has yet to be undertaken at Enmore, however a preliminary assessment in May 2000 indicated the population to be over 2 000, with adults up to 2.5 m high and 4 m wide, with many seedlings present.
The tenure and ownership of the sites of known populations of Grevillea beadleana is shown in Table 1. Four areas are reserved in the conservation reserve system and managed by the Department of Environment and Conservation (DEC). The largest occurrence of G. beadleana, at Binghi near Torrington, is present within a number of different tenures, including the Torrington State Recreation Area managed by DEC and Crown Leasehold land, with two outlying populations on freehold land.
Populations within National Parks are zoned as Existing National Parks, while those populations on private and leasehold land, State Recreation Area and Nature Reserves are currently zoned as General Rural. It is anticipated that the populations in State Recreation Area and Nature Reserves will be zoned as Existing National Park and Nature Reserves in the future.
Figure 2. The general locations of G. beadleana populations in north east New South Wales.
|Location||Tenure||Local Govt.||LEP zoning|
|Chambigne Nature Reserve||Nature Reserve||Nymboida||1(a) - General Rural|
|Guy Fawkes River NP -east||National Park||Nymboida||8(a) - Existing National Parks|
|Guy Fawkes River NP - west||National Park||Guyra||To be determined|
|Torrington SRA||State Recreation Area||Tenterfield||1(a) - General Rural|
|Torrington leasehold||Crown Leasehold||Tenterfield||1(a) - General Rural|
|Torrington private land||Freehold||Tenterfield||1(a) - General Rural|
|Oxley Wild Rivers NP||National Park||Dumaresq||8(a) - Existing National Parks|
|Enmore private land||Freehold||Dumaresq||1(a) - General Rural|
Because the loss of genetic diversity within a species, especially one that has never been abundant, can be catastrophic, and can cause inbreeding depression, the level of genetic diversity within and between the various populations of Grevillea beadleana is being investigated. Preliminary results from starch gel electrophoresis of young leaf material from plants cultivated at the University of New England (UNE) showed intra-population variation within the Binghi and Guy Fawkes River National Park populations. The Chambigne Nature Reserve population varied genetically from the other two but not within itself (C. Gross unpublished data).
All areas of known potential habitat, in the Binghi and Enmore areas, Guy Fawkes River National Park and Chambigne Nature Reserve constitute significant habitat.
All areas of known habitat in the Torrington State Recreation Area, Oxley Wild Rivers and Guy Fawkes River National Parks and Chambigne Nature Reserve areas require assessment to determine whether they are Critical Habitat within the meaning of the TSC Act.