Grevillea obtusiflora subsp. obtusiflora and subsp. fecunda Recovery Plan

NSW National Parks and Wildlife Service, September 2001
ISBN 0 731 36281 0

5 Distribution and habitat

5.1 Distribution

Grevillea obtusiflora subsp. obtusiflora

G. obtusiflora subsp. obtusiflora occurs in and adjacent to Clandulla State Forest near Rylstone in the Central Tablelands, NSW (Figure 3). Preliminary surveys show that the plant is limited to a small area of the forest. The forest is bisected by Carwell Creek, which flows north to the Cudgegong River. G. obtusiflora subsp. obtusiflora is found on the plateau east of the Carwell Creek.

Site O1 (Figure 4) is located within Clandulla State Forest and comprises a total of nine groups of plants within an area of 400 square metres. Each stand comprises from 50 to several hundred plants. Site O2 is located on the boundary of State Forest and Rylstone Shire Council roads, occupies ten square metres, and consists of approximately 100 plants. Detailed information on each site for Grevillea obtusiflora subsp. obtusiflora is included as Appendix 1.

Cunningham found the type specimen in 1882 in 'Brushy hills N. of Bathurst'. It is not known whether the known sites include the collection site of the syntypic series.

Grevillea obtusiflora subsp. fecunda

Grevillea obtusiflora subsp. fecunda occurs in the Capertee Valley, west of Lithgow. Three sites are known. Site F1 (Figure 5) is located primarily on the raised roadside verges on Home Hills Road. Site F1 extends for approximately 50 metres and contains approximately 60 individual plants. Site F2 is located in Port Macquarie Rd and extends for 600 metres; and has greater than 500 plants. Site F3 (Figure 6) is located on the slopes of Pantoneys Crown within Gardens of Stone National Park where 350 plants occupy an area of approximately 300 square metres.

Detailed information on each site for Grevillea obtusiflora subsp. fecunda is included as Appendix 1.

Figure 3 shows the distribution of both subspecies.

Distribution of G. obtusiflora subsp. fecunda and subsp. obtusiflora
Figure 3 - Distribution of G. obtusiflora subsp. fecunda and subsp. obtusiflora
Clandulla State Forest
Figure 4 - Site O1 - Clandulla State Forest
Home Hills Road
Figure 5 - Site F1 - Home Hills Road
Pantoneys Crown
Figure 6 - Site F3 - Pantoneys Crown

5.2 Habitat

5.2.1 Climate

The area experiences hot, dry summers and moist to wet winters, with an average rainfall of 750-850 mm.

5.2.2 Vegetation

Grevillea obtusiflora subsp. obtusiflora

G. obtusiflora subsp. obtusiflora occurs in open forest dominated by the following species.

Sites O1 and O2

Canopy : Eucalyptus crebra; E. dealbata; E. tenella.
Middle stratum : Callistemon linearis, Acacia buxifolia, Acacia elongata,
Understorey : Leucopogon sp., Caustis flexuosa, Dianella sp, Patersonia sp.

A list of the species associated with G. obtusiflora subsp. obtusiflora is provided in Appendix 2.

Grevillea obtusiflora subsp. fecunda.

G. obtusiflora subsp. fecunda occurs in open forest dominated by the following species.

Sites F1 and F2.

Canopy : Eucalyptus tenella, E. fibrosa, E. macrorhyncha, E. punctata, Callitris endlicheri
Middle stratum : Acacia buxifolia, Leptospermum continentale, Monotoca elliptica.
Ground stratum : Persoonia linearis, Indigofera sp., Pomax umbellata.

Site F3

Canopy : Eucalyptus crebra, E. beyeriana.
Middle Stratum : Acacia buxifolia, Acacia ixiophylla, Isopogon aneminifolius.
Ground Stratum : Lomandra glauca, Styphelia triflora, Goodenia sp.

A list of the species associated with Grevillea obtusiflora subsp. fecunda is provided in Appendix 2.

In regard to G. obtusiflora subsp. fecunda, Makinson (1997) has suggested that the presence of Eucalyptus tenella may prove to be a good indicator for the taxon.

5.2.3 Soil Characteristics

In eastern Australia, most Grevillea species grow in sandstone-derived soils which are usually shallow, and both hard to wet and slow to drain (Olde and Marriott 1994). Where Grevilleas occur, the sandy-loam soils are highly acidic (pH3 to pH4) and usually contain considerable humus (Olde and Marriott 1994).

G. obtusiflora subsp. obtusiflora occurs on sandy loam soil (Olde and Marriott, 1995) derived from shale, siltstone, conglomerate and sandstone associated with the geology of the Permian, Shoalhaven Group.

G. obtusiflora subsp. fecunda occurs on structured loam soil derived from the shale, conglomerate and sandstone associated with the geology of the Permian, Shoalhaven Group.

Makinson (1997) refers to the distinctive orange loamy soil with sandstone boulders on which G. obtusiflora subsp. fecunda occurs. Makinson (1997) further suggests it is likely that G. obtusiflora subsp. fecunda is substrate specific, and that this soil type may prove to be a good indicator for this taxon.

5.2.4 Tenure

Grevillea obtusiflora subsp. obtusiflora

The known sites of G. obtusiflora subsp. obtusiflora occur on State Forest, freehold land (as an inholding within State Forest), and on roads managed by the Rylstone Shire Council. The sites are within the Parish of Clandulla and the Rylstone local government area.

No voluntary conservation agreements have been entered into for the freehold land containing G. obtusiflora subsp. obtusiflora.

Clandulla State Forest is classified under the Preferred Management Priority system. The area is classified as either multiple use natural forest, Special Emphasis, or Undeveloped Natural Forest.

Clandulla State Forest was dedicated on 8 June 1917. The forest has a history of low intensity harvesting operations producing mining props, charcoal, fencing timber and firewood. The immediate area in which G. obtusiflora subsp. obtusiflora occurs contains trees that are of low timber value and has not been logged for approximately 40 years, although the area has been available for the harvesting of minor forest products. The first Occupational Permit for grazing Clandulla State Forest was issued on 15 December 1948. Although grazing is recorded in the Capertee and Rylstone areas since the middle 1800s, there is little information about its duration, intensity and extent. Grazing has the ability to alter species composition, soils crusts, and vegetation structure, however the effect of grazing in this area is not known.

Table 1: Tenure of G. obtusiflora subsp. obtusiflora sites.
Site No. Tenure Manager
O1
Clandulla State Forest
Freehold
State Forests of NSW
Private Landholder
O2
Clandulla State Forest
Council road
State Forests of NSW
Rylstone Shire Council

Grevillea obtusiflora subsp. fecunda

The greatest numbers of Grevillea obtusiflora subsp. fecunda occur at sites along two unsealed Rylstone Shire Council roads and adjoining freehold land, within the Parish of Capertee (sites F1 & F2). Site F3 occurs within the Gardens of Stone National Park. No voluntary conservation agreements have been entered into for the freehold land containing G. obtusiflora subsp. fecunda.

The area in which the largest numbers are found has been used for cattle grazing in excess of 120 years, accordingly the taxon and its habitat is likely to have been subjected to grazing for part of this period.

Despite the variation in tenure between the different sites of both subspecies, it is likely that all the sites have been subjected to comparable levels of grazing by sheep and cattle, and to the harvesting of timber.

Table 2: Tenure of Grevillea obtusiflora subsp. fecunda sites.
Site No. Tenure Manager
F1
Council road
Freehold
Rylstone Shire Council
Private Landholder
F2
Council road
Freehold
Rylstone Shire Council
Private Landholder
F3
Gardens of Stone
National Park
National Parks and Wildlife
Service