Robertson rainforest in the Sydney Basin Bioregion - endangered ecological community listing

The Scientific Committee, established by the Threatened Species Conservation Act, has made a Final Determination to list the Robertson Rainforest in the Sydney Basin Bioregion, as an ENDANGERED ECOLOGICAL COMMUNITY on Part 3 of Schedule 1 of the Act. Listing of Endangered Ecological Communities is provided for by Part 2 of the Act.

This determination has been superseded by the 2011 minor amendment Determination.

NSW Scientific Committee - final determination

The Scientific Committee has found that:

1. Robertson Rainforest in the Sydney Basin Bioregion is the name given to the ecological community characterised by the species assemblage listed in 2 below. The community occurs on high nutrient soils in high rainfall areas of the Southern Highlands. All sites are within the Sydney Basin Bioregion.

2. Robertson Rainforest is characterised by the following assemblage:

  • Acacia melanoxylon
  • Acmena smithii
  • Acronychia oblongifolia
  • Alectryon subcinereus
  • Alphitonia excelsa
  • Aphanopetalum resinosum
  • Arthropteris tenella
  • Asplenium attenuatum
  • Asplenium australasicum
  • Asplenium flabellifolium
  • Asplenium flaccidum
  • Australina pusilla
  • Austrocynoglossum latifolium
  • Blechnum nudum
  • Blechnum patersonii
  • Blechnum wattsii
  • Carex appressa
  • Cassinia trinerva
  • Celastrus australis
  • Ceratopetalum apetalum
  • Cissus hypoglauca
  • Citriobatus pauciflorus
  • Clematis aristata
  • Clematis glycinoides
  • Coprosma quadrifida
  • Cryptocarya glaucescens
  • Cyathea australis
  • Cyathea leichhardtiana
  • Dendrobium pugioniforme
  • Dennstaedtia davallioides
  • Dicksonia antarctica
  • Diospyros australis
  • Diplazium australe
  • Doodia aspera
  • Doryphora sassafras
  • Elaeocarpus holopetalus
  • Elaeocarpus kirtonii
  • Elaeocarpus reticulatus
  • Elatostema reticulatum
  • Eucalyptus fastigata
  • Eucryphia moorei
  • Eustrephus latifolius
  • Ficus coronata
  • Fieldia australis
  • Galium propinquum
  • Geitonoplesium cymosum
  • Geranium homeanum
  • Grammitis billardieri
  • Guioa semiglauca
  • Gymnostachys anceps
  • Hedycarya angustifolia
  • Helicia glabrifolia
  • Hibbertia scandens
  • Histiopteris incisa
  • Hydrocotyle laxiflora
  • Hymenanthera dentata
  • Hymenophyllum cupressiforme
  • Hymenophyllum flabellatum
  • Lastreopsis acuminata
  • Lastreopsis decomposita
  • Lastreopsis microsora
  • Livistona australis
  • Lomandra longifolia
  • Marsdenia rostrata
  • Microsorum pustulatum subsp. pustulatum
  • Microsorum scandens
  • Morinda jasminoides
  • Muellerina eucalyptoides
  • Notelaea venosa
  • Olearia argophylla
  • Ozothamnus diosmifolius
  • Ozothamnus ferrugineus
  • Palmeria scandens
  • Pandorea pandorana
  • Parsonsia brownii
  • Parsonsia straminea
  • Pellaea falcata
  • Pennantia cunninghamii
  • Pimelea ligustrina
  • Pittosporum revolutum
  • Pittosporum undulatum
  • Plantago debilis
  • Plectorrhiza tridentata
  • Polyosma cunninghamii
  • Polyphlebium venosa
  • Polyscias murrayi
  • Polyscias sambucifolia
  • Polystichum proliferum
  • Prostanthera lasianthos
  • Pteris umbrosa
  • Pyrrosia rupestris
  • Quintinia sieberi
  • Ranunculus lappaceus
  • Ranunculus plebeius
  • Rapanea howittiana
  • Rubus Moluccanus var. trilobus
  • Ripogonum album
  • Rubus nebulosus
  • Rubus rosifolius
  • Sambucus australasica
  • Sarcochilus falcatus
  • Sarcopetalum harveyanum
  • Schizomeria ovata
  • Smilax australis
  • Solanum aviculare
  • Solanum pungetium
  • Stellaria flaccida
  • Stenocarpus salignus
  • Sticherus lobatus
  • Symplocos thwaitesii
  • Synoum glandulosum
  • Tasmannia insipida
  • Tristaniopsis collina
  • Tylophora barbata
  • Urtica incisa
  • Veronica plebeia
  • Viola hederacea

3. The total species list of the flora and fauna of the community is considerably larger than that given in 2 (above), with many species present in only one or two sites or in very small quantity. The community includes vertebrates and invertebrates, many of which are poorly known. Invertebrate species may be restricted to soils or canopy trees and shrubs. In any particular site not all of the assemblage listed above may be present. At any one time, seeds of some species may only be present in the soil seed bank with no above-ground individuals present. The species composition of the site will be influenced by the size of the site and by its recent disturbance history. The number of species and the above-ground composition of species will change with time since fire, and may also change in response to changes in fire frequency.

4. Robertson Rainforest is a warm temperate/cool temperate rainforest type characterised by Quintinia sieberi, Polyosma cunninghamia and Doryphora sassafras (Mills & Jakeman 1995). Eucryphia moorei was probably common along streams. Tree and shrub species typically associated with this rainforest type are Acmena smithii, Acacia melanoxylon, Quintinia sieberi, Hymenanthera dentata, Coprosma quadrifida, Tasmannia insipida and occasionally Ceratopetalum apetalum. Cool temperate components include Olearia argophylla, Hedycarya angustifolia, Eucryphia moorei, Dicksonia antarctica and Parsonsia brownii. Ground cover is a dense fern cover including Lastreopsis microsora and Microsorum pustulatum subsp. pustulatum.

5. Robertson Rainforest is found on high fertility soils derived generally from Tertiary basalts (mainly the Robertson Basalt and Kangaroo Valley Basanite), at high altitudes (500-750 m) and under high rainfalls (1000-1600 mm per annum) (Mills & Jakeman 1995).

6. Robertson Rainforest is or has been known to occur in the Wingecarribee and Shoalhaven Local Government Area, but may occur elsewhere in the Sydney Basin Bioregion. It has been reported from the Robertson plateau and Cambewarra Range (Mills & Jakeman 1995).

7. Disturbed Robertson Rainforest remnants are considered to form part of the community including areas where the vegetation would respond to assisted natural regeneration, such as where the natural soil and associated seedbank is still at least partially intact.

8. Robertson Rainforest has been extensively cleared for agriculture and rural development. About 400-600 ha or about 20% of its original extent is estimated to survive though mostly as fragmented remnants (Mills 1988). Remnants are often dominated by Acmena smithii, Doryphora sassafras and Acacia melanoxylon.

9. A remnant of Robertson Rainforest is conserved in Robertson Nature Reserve at Robertson.

10. Much of the remaining area of Robertson Rainforest is highly fragmented with much of it occurring on private land. Threatening processes include invasion of exotic weed species including Ligustrum sinense, Hedera helix, Lonicera japonica, Ilex aquifolium and clearing, grazing, trampling and further fragmentation.

11. In view of the originally restricted distribution of this community, its inadequate representation within conservation reserves, and threats from fragmentation and weed invasion, the Scientific Committee is of the opinion that Robertson Rainforest in the Sydney Basin Bioregion is likely to become extinct in nature in New South Wales unless the circumstances and factors threatening its survival or evolutionary development cease to operate and that the community is eligible for listing as an endangered ecological community.

Proposed Gazettal date: 15/06/01

Exhibition period: 15/06/01 - 20/07/01


Mills, K. (1988) The clearing of Illawarra rainforest: problems in reconstructing pre-european vegetation patterns. Australian Geographer 19(2): 230-240.

Mills, K. & Jakeman, J. (1995) Rainforests of the Illawarra District. (Coachwood Publishing:Jamberoo)