Approved NSW and National Recovery Plan for the Grevillea beadleana

Threatened Species Unit, North East Branch
New South Wales Department of Environment and Conservation, 2004
ISBN: 174122 135 8

4. Habitat

4.1 Binghi Torrington State Recreation Area

The populations of Grevillea beadleana on the Crown Leasehold land (Figure 2) and within the Torrington State Recreation Area may be contiguous. Further survey work is required in the region. Binghi is the largest naturally vegetated region on the north-west slopes of New South Wales (Benson 1991). The main land-uses in the area include tin mining and rough cattle grazing. The National Parks Association of NSW proposed the area as a National Park in 1976. However, this application was withdrawn in response to opposition from local miners and graziers (Benson 1991). The area was identified as wilderness under section 6 of the Wilderness Act 1987 but has not been formally declared.

Fires are not frequent in the area of the Binghi population. The property owners at Grevillea Downs suggest that the last fire in the area was during the 19823 season (McWhinney pers. comm.) although Benson (1991) notes that ...on the knoll in the Binghi area, approximately half of the mature adults were killed in a 1988 fire. Few seedlings are present. Part of this area burnt in November 2002, however investigation of the response of G. beadleana to this event has yet to occur.

Many of the plants are estimated to be up to 30 years old, although the longevity of Grevillea beadleana is currently not known. This estimate is based on the time since the last large fire that burnt most of the area occupied by G. beadleana (19823) and the fact that large mature plants exist in unburnt areas in 1988. Goats have been seen throughout the area occupied by Grevillea beadleana (B. McWhinney pers. comm.), and while there was no evidence of goat or other stock grazing upon plants during research undertaken by Durbin in 1996, it is thought that the stunted apical areas and a multi-sided branch spreading structure of some plants may be indicative of goat grazing (C. Gross pers. comm.).

Topography and elevation

The first populations surveyed in this region were found alongside Oaky Creek and on a flat, rocky knoll 1 km to the west (Benson 1991). Since this work, plants have been found throughout the area at elevations ranging from 600 m to 900 m above sea level on undulating terrain, steep slopes and flat plateaux.

Geology and soils

The parent material is Mole Creek Granite, which extends throughout the Binghi area. The rock is extremely siliceous, containing a greater than 75% silica content. The soil formed, is a relatively fine-grained loamy-sand mixture. The soil is poor in nutrients and is acidic (Benson 1991).

Rainfall

Based on data from several nearby properties, the Binghi area receives approximately 800 mm of rain annually (Bureau of Meteorology in Benson 1991). This site would experience higher temperatures and thus greater evaporation rates than the Guy Fawkes River National Park population (Benson 1991).

Associated vegetation

The vegetation at Binghi is woodland with a shrubby understorey component that is sparse on the rocky outcrops. Common trees include Eucalyptus prava, E. andrewsii, E subtilior, Callitris endlicheri and Angophora floribunda (Clarke et al. 1998).

Common shrub and forb understorey species include Acacia granitica, Baeckea densifolia, Leptospermum brachyandrum, L. brevipes, Notelaea linearis, Mirbellia speciosa, Persoonia terminalis subsp. terminalis and Phebalium squamulosum. Grasses and sedges that frequently occur as mid-dense ground cover include Schoenus ericetorum, Xanthorrhoea glauca, Lepyrodia leptocaulis, Lomandra longifolia, Aristida armata, Cymbopogon obtectus and Eragrostis brownii (Benson 1991).

4.2 Guy Fawkes River National Park - eastern population

Guy Fawkes River National Park was gazetted in 1972. Prior to this the land was vacant Crown land with licensed occupancies for grazing in some parts (Reid et al. 1996). The eastern population of Grevillea beadleana is located within an area declared in 1994 as wilderness under the Wilderness Act 1987. The population of G. beadleana is located north of Jordan's trail, along the rim of the gorge, and adjacent to the escarpment walking track. The population exists in an area of 4.25 hectares (Dwyer unpublished data; Gross et al. unpublished data; Streat 1997) with most of the older plants nestled among rocks and crevices that afford protection from fire. Many of the seedlings are growing in the loose scree between and below the rocky ridges. The scree substrate is active and plants are particularly vulnerable to disturbance from landslides.

Topography and elevation

This population occurs at an elevation between 900 m and 1000 m on small rocky ridges and interstitial scree that form part of a steeply sloping bluff adjoining an undulating plateau.

Geology and soils

The rock outcropping on the bluff is silica-rich (>75%), leucocratic, felsphatic granite and is part of a complex of granitic outcrops mapped as the Chaelundi Granite. Compared to another granitic rock specimen from Guy Fawkes Crags, 8 kms to the north (where Grevillea beadleana is absent), the rock has a low content of ferromagnesium minerals. The soil formed from this parent material is a skeletal, highly siliceous, sandy-loam substrate.

Rainfall

The rainfall is estimated to be approximately 1000 mm per annum (Bureau of Meteorology in Benson 1991).

Associated vegetation

The vegetation is sparse among the outcrops and currently large trees are dying as a result of unstable substrate conditions. In the upper stratum Eucalyptus campanulata and the rare E. michaeliana dominate with the occasional Lophostemon confertus. The middle stratum is dominated by a species of Leptospermum, Allocasuarina littoralis and Notelaea microcarpa along with Grevillea beadleana. Scattered clumps of grasses, herbs and sedges make up the ground stratum with the most common species being Gonocarpus teucrioides, Lepidosperma laterale, Poa sieberi, Stipa ramosissma, Pomax umbellata and a species of Aristida (Benson 1991).

4.3 Guy Fawkes River National Park - western population

The area where Grevillea beadleana occurs was purchased for inclusion in the Guy Fawkes River National Park in 1997. Prior to this the land was vacant Crown land with licensed occupancies for grazing in some parts (Reid et al. 1996). The area was identified as wilderness under section 6 of the Wilderness Act 1987 but has not been formally declared.

Topography and elevation

The area where Grevillea beadleana occurs is on a small rocky cliff in the Aberfoyle River gorge at an elevation of approximately 500 m, with a predominantly southerly aspect. The surrounding escarpment rises steeply to over 1000 m, and the Aberfoyle gorge is aligned in a north-east to south direction.

Geology and soils

The substrate where the western population occurs is reported to be skeletal soils over metamorphosed Permian sediments (P. Gilmore pers. comm.). These sediments include greywacke, slate siliceous argillite and pebbly mudstone (NSW Department of Mineral Resources 1969).

Rainfall

The rainfall is estimated to be approximately 800 mm per annum (Bureau of Meteorology in Benson 1991).

Associated vegetation

The associated vegetation in the area where the Grevillea beadleana plants were recorded includes open forest consisting of Eucalyptus eugenoides, E. tereticornis, Angophora subvelutina, Allocasuarina littoralis, Hovea lanceolata, Jacksonia scoparia, Parsonsia straminea, Melichrus adpressus, Lomandra sp., Aristida sp., and Goodenia hederacea ssp. hederacea (P. Gilmour pers. comm.).

4.4 Chambigne Nature Reserve

This site is located within Chambigne Nature Reserve south-west of Grafton, in the headwaters of Shannon Creek which forms part of the catchment of the lower Orara River. Although the land is managed by DEC access to the land is negotiated through private property. The population is located on a mesa-like outcrop. Six of the plants are huddled on the western side of the site on a rock ledge that probably affords protection from fire.

The Nature Reserve requires a thorough investigation for further occurrences of Grevillea beadleana and for a full floristic inventory. Surveys of the area in 1994 and 1995 revealed that there were only nine G. beadleana plants present over an area of about 2 hectares and later surveys only located six plants. A subsequent investigation in early 1998 found the population reduced to three adult plants and one seedling with the cause of the decline unknown.

Topography and elevation

The area is an isolated plateau rising approximately 150200 m above the adjacent valleys of Deep Creek to the west and Shannon Creek to the east. Cliffs and very steep slopes bound the area on the west and south, and more moderate slopes to the east and north. In places on the southern boundary the cliffs are up to 75 m high and are a series of broken ledges with numerous caves, overhangs and clefts. The top of the plateau is semi-circular, with a long ridge on the western side extending to the north. The plateau is relatively flat, with a number of high points rising to a maximum of 285 m above sea level. The area forms the upper catchment of an unnamed tributary of Shannon Creek.

Geology and soils

The geology of the area comprises Jurassic Kangaroo Creek Sandstone, consisting of quartz sandstone and feldspathic quartz sandstone. This substrate produces a coarse-grained sandy soil, with free drainage. The high quartz content produces a soil of low fertility. Although no soil samples have yet been analysed, descriptions have been of poor, skeletal sandy type soil.

Rainfall

The rainfall is approximately 1200 mm per year.

Associated vegetation

The vegetation is dry open forest dominated by Eucalyptus psammitica and Corymbia gummifera with a dry shrub understorey. Pockets of mesic vegetation may be found in small areas, such as those with impeded drainage, at the base of cliffs or in fire-free areas such as cliff benches and clefts. The area contains populations of two Endangered Species (Grevillea beadleana and Melichrus hirsutus), one undescribed species (Bertya sp. nov.), one rare species (Dodonaea hirsuta) and one poorly known species (Eucalyptus psammitica) (Sheringham & Westaway 1995).

Other species recorded at this site include Acacia concurrens, A. hispidula, A. venosa, Allocasuarina littoralis, Brachyloma daphnoides, Chloanthes parviflora, Daviesia wyattiana, Eriachne pallescens, Hibbertia acuminata, H. vestita, Hovea longifolia, Jacksonia scoparia, Leptospermum trinervium, Melichrus procumbens, Patersonia sericea, Phebalium woombye, Phyllanthus hirtellus, Platysace ericoides, Tetratheca thymifolia, Trachymene incisa, Xanthorrhoea johnsonii (National Parks and Wildlife Service 1995). Further detailed surveys are required.

4.5 Enmore - Oxley Wild Rivers National Park

This site, located on private property and within the Oxley Wild Rivers National Park, is 25 kms south of Armidale, in the catchment of the Macleay River. Access to the land is through private property and is currently being negotiated with the landowner. The area requires a thorough investigation for further occurrences of Grevillea beadleana and for a full floristic inventory. The area was identified as wilderness under section 6 of the Wilderness Act 1987 but has not been formally declared. This section of Oxley Wild Rivers National Park was included on the World Heritage List in 1994, as part of the Central Eastern Rainforest Reserves of Australia.

Topography and elevation

The area is on the edge of the New England tableland, at an elevation of 950 m above sea level. The slopes of the escarpment are very steep, falling away for 450 m to Salisbury Waters.

Geology and soils

A preliminary investigation revealed that the underlying bedrock is granite, producing a sandy loam substrate (L. Copeland pers. comm.). Geology maps for the area indicate that the granite type is Blue Knobby Ademellite, a biotite ademellite (Department of Mineral Resources 1988).

Rainfall

The estimated rainfall is 750 mm per year.

Associated vegetation

The vegetation is a layered woodland dominated by Eucalyptus youmanii and E. bridgesiana with a shrub understorey of Leptospermum brevipes and Grevillea beadleana. The ground cover consists of a well developed grass layer of Themeda australis and Aristida spp. Rare species recorded at the site include Zieria sp. nov, an undescribed species, Eucalyptus magnificata and Acacia ingramii (L. Copeland pers. comm.).

4.6 Geographic Information System (GIS) Predictive Modelling

Durbin (1996) developed a predictive model for Grevillea beadleana that showed that the area between the Queensland-NSW border and Glen Innes contains the most suitable habitat for the species. The model selected current and historical sites and highlighted many other areas throughout the region that may contain suitable habitat for the species. The Binghi region was not included in the model due to inadequate data being available for this area.