Bangalay sand forest, Sydney Basin and South East Corner bioregions - endangered ecological community listing

The Scientific Committee, established by the Threatened Species Conservation Act, has made a Final Determination to list Bangalay Sand Forest of the Sydney Basin and South East Corner bioregions as an ENDANGERED ECOLOGICAL COMMUNITY in Part 3 of Schedule 1 of the Act. Listing of endangered ecological communities is provided for by Part 2 of the Act.

NSW Scientific Committee - final determination

The Scientific Committee has found that:

1. Bangalay Sand Forest of the Sydney Basin and South East Corner bioregions is the name given to the ecological community associated with coastal sand plains of marine or aeolian origin. It occurs on deep, freely draining to damp sandy soils on flat to moderate slopes within a few km of the sea and at altitudes below 100 m. Bangalay Sand Forest is characterised by the assemblage of species listed in paragraph 2 and typically comprises a relatively dense or open tree canopy, an understorey of mesophyllous or sclerophyllous small trees and shrubs, and a variable groundcover dominated by sedges, grasses or ferns.

2. Bangalay Sand Forest of the Sydney Basin and South East Corner bioregions is characterised by the following assemblage of species:

3. The total species list of the community is larger than that given above, with many species present only in one or two sites, or in low abundance. The species composition of a site will be influenced by the size of the site, recent rainfall or drought conditions and by its disturbance (including grazing, land clearing and fire) history. The number and relative abundance of species will change with time since fire, and may also change in response to changes in fire frequency or grazing regime. At any one time, above-ground individuals of some species may be absent, but the species may be represented below ground in the soil seed banks or as dormant structures such as bulbs, corms, rhizomes, rootstocks or lignotubers. The list of species given above is mainly of vascular plant species, however the community also includes micro-organisms, fungi, cryptogamic plants and a diverse fauna, both vertebrate and invertebrate. These components of the community are poorly documented.

4. Bangalay Sand Forest of the Sydney Basin and South East Corner bioregions typically has a dense to open tree canopy, approximately 5 - 20 m tall, depending on exposure and disturbance history. The most common tree species include Eucalyptus botryoides (Bangalay) and  Banksia integrifolia subsp.  integrifolia (Coast Banksia), while  Eucalyptus pilularis (Blackbutt) and  Acmena smithii (Lilly Pilly) may occur in more sheltered situations, and  Casuarina glauca (Swamp Oak) may occur on dunes exposed to salt-bearing sea breezes or where Bangalay Sand Forest adjoins Swamp Oak Floodplain Forest of the NSW North Coast, Sydney Basin and South East Corner bioregions, as listed under the  Threatened Species Conservation Act 1995. The open shrub stratum may be dominated by sclerophyllous species, such as  Banksia serrata (Old Man Banksia),  Leptospermum laevigatum (Coast Teatree) and  Monotoca elliptica, or mesophyllous, species, such as  Breynia oblongifolia (Coffee Bush) and  Pittosporum undulatum (Sweet Pittosporum), or a combination of both. Shrubs may vary in height from one to ten m tall. The groundcover varies from open to dense, and may be sparse where the tree canopy is dense or where there is a thick litter of leaves and branches. Dominant species include  Dianella spp. (Blue Flax Lilies),  Lepidosperma concavum, Lomandra longifolia (Spiny-headed Matrush),  Pteridium  esculentum (Bracken), and the grasses  Imperata cylindrica var.  major (Blady Grass),  Microlaena stipoides var.  stipoides (Weeping Grass) and  Themeda australis (Kangaroo Grass), while herbs, such as  Desmodium gunnii,  Dichondra repens (Kidney Weed),  Pratia purpurascens (Whiteroot) and  Viola hederacea (Ivy-leaved Violet), are scattered amongst the larger plants. Vines of  Glycine clandestina, Hardenbergia violacea (False Sarsparilla),  Kennedia rubicunda (Running Postman) , Marsdenia rostrata (Common Milk Vine) and  Stephania japonica var.  discolor (Snake Vine) scramble through the groundcover and occasionally over shrubs or tree trunks.

5. Bangalay Sand Forest of the Sydney Basin and South East Corner bioregions is currently known from parts of the Local Government Areas of Sutherland, Wollongong, Shellharbour, Kiama, Shoalhaven, Eurobodalla and Bega Valley but may occur elsewhere in these bioregions. Bioregions are defined in Thackway and Creswell (1995).

6. A number of vegetation surveys and mapping studies have been carried out across the range of Bangalay Sand Forest of the Sydney Basin and South East Corner bioregions. In the Sydney-South Coast region, this community includes 'Ecotonal Coastal Hind Dune Swamp Oak-Bangalay Shrub Forest' (ecosystem 27) excluding those stands that are dominated by Casuarina glauca and 'Coastal Sands Shrub/Fern Forest' (ecosystem 28) of Thomas  et al. (2000); 'Littoral Thicket' (map unit 63) and part of 'Coastal Sand Forest' (map unit 64) of Tindall  et al. (2004); 'Coastal Sand Bangalay-Blackbutt Forest' (map unit 25) of NPWS (2002); and 'Dry Dune Shrub Forest' of Keith and Bedward (1999). Bangalay Sand Forest of the Sydney Basin and South East Corner bioregions is included within the 'South Coast Sands Dry Sclerophyll Forests' vegetation class of Keith (2002, 2004). There may be additional or unmapped occurrences of Bangalay Sand Forest within and beyond these surveyed areas.

7. Near its northern limit in the Bundeena area, Bangalay Sand Forest co-occurs with Kurnell Dune Forest in the Sutherland Shire and City of Rockdale, which is listed as an Endangered Ecological Community in Part 3 of Schedule 1 of the Act. In this area, Bangalay Sand Forest is generally restricted to foredunes and hind dunes of beaches, while Kurnell Dune Forest generally occurs on sheltered sand flats further from the immediate influence of the sea. Characteristic species of Kurnell Dune Forest, such as Angophora costata, Banksia ericifolia, Cupaniopsis anacardioides, Endiandra sieberi,  Eucalyptus robusta and  Maclura cochinchinensis, are not common components of Bangalay Sand Forest. However, the two communities may intergrade where they co-occur. This Determination and the Determination of Kurnell Dune Forest collectively encompass all intermediate stands of vegetation between the two communities.

8. Another Endangered Ecological Community, Umina Coastal Sandplain Woodland in the Sydney Basin bioregion, occupies a similar sandplain habitat to the north of Sydney. However, this community occupies podsolised sands that are rich in iron (Burges & Drover 1952), as distinct from the humic podsols that characterise Bangalay Sand Forest, and is dominated by Angophora floribunda with  E. paniculata, while  E. botryoides predominates only in the vicinity of the beach. In addition, Umina Coastal Sandplain Woodland includes a greater diversity of mesic understorey species and  Acacia species than Bangalay Sand Forest.

9. Bangalay Sand Forest of the Sydney Basin and South East Corner bioregions is threatened by land clearing; degradation and disturbance associated with heavy recreational use; frequent burning; rubbish dumping; and weed invasion. These threats are generally associated with existing and proposed urban development along the coast. However, areas of Bangalay Sand Forest within conservation reserves, including Royal, Seven Mile Beach, Conjola, Meroo, Murramarang, Eurobodalla and Biamanga National Parks, are exposed to degradation by visitor overuse due to their proximity to popular beaches and camping areas.

10. Available vegetation mapping indicates that Bangalay Sand Forest has suffered substantial levels of clearing. The coastline between Gerroa and Bermagui includes an estimated area of about 3450 hectares, representing one-quarter of the estimated pre-1750 distribution of the community (ecosystems 27 and 28 of Thomas et al. 2000). Similarly, Tindall  et al. (2004) map about 2200 hectares of Littoral Thicket, representing about one-third of the its estimated pre-European distribution between Sydney and Moruya. South of Bermagui, Keith & Bedward (1999) mapped a further 650 hectares, representing less than two-fifths of the estimated pre-1750 distribution. However, recent reconnaissance suggests that these studies may have over-estimated the remaining area of Bangalay Sand Forest (J. Miles, pers. comm.). North of Gerroa, only small fragments of the community persist, for example, on Minnamurra Spit (Mills 2000), around Primbee and Windang (NPWS 2002), Bundeena and Taren Point. Overall, these estimates indicate large reductions in the geographic distribution of the community. Clearing of native vegetation is listed as a Key Threatening Process under the  Threatened Species Conservation Act (1995).

11. Some areas of Bangalay Sand Forest are exposed to frequent burning, particularly around camping areas, towns and other sources of ignition. High frequency fire alters species composition by favouring fire-tolerant rhizomatous grasses, sedges and ferns at the expense of woody plants that are slow to regenerate after fire (Keith 1996). Elimination of woody species by frequent burning is likely to be accelerated by grazing. These processes of degradation represent large reductions in the ecological function of the community. High frequency fire resulting in disruption of life cycle processes in plants and animals and loss of vegetation structure and composition is listed as a Key Threatening Process under the Threatened Species Conservation Act (1995).

12. Weed invasion occurs where Bangalay Sand Forest is exposed to disturbance and degradation. Common weed species include Asparagus spp.,  Chrysanthemoides monilifera subsp.  rotundata (Bitou Bush), introduced forms of  Cynodon dactylon (Couch),  Cirsium vulgare (Spear Thistle) , Conyza bonariensis (Fleabane) , Hypochaeris radicata (Cats Ear) , Ipomea spp. (Morning Glory spp.),  Lantana camara, Pennisetum clandestinum (Kikuyu). These and other weed species may achieve considerable abundance within stands of Bangalay Sand Forest, indicating a large reduction in ecological function of the community. Invasion of native plant communities by exotic perennial grasses is listed as a Key Threatening Process under the  Threatened Species Conservation Act (1995).

13. Additions to the coastal reserve system and land use zoning have protected some stands of Bangalay Sand Forest from clearing. However, pressures associated with increasing human populations and recreational activity on the coast continue to intensify, especially where stands of the community occur in the vicinity of coastal villages and urban centres, and where new reserves involve the establishment of camping areas and other visitor infrastructure. Disturbance associated with increased human access contributes particularly to habitat degradation, increased frequencies of bushfire ignitions, and weed invasion, posing major threats even on land managed for conservation. In addition to the processes outlined above, activities such as illegal fire wood collection by campers and coastal residents may threaten habitat for vertebrate and invertebrate fauna and disrupt nutrient and carbon cycling. Removal of dead wood and dead trees is listed as a Key Threatening Process under the Threatened Species Conservation Act (1995). These processes may result in a large reduction in ecological function of the community.

14. In view of the above, the Scientific Committee is of the opinion that Bangalay Sand Forest of the Sydney Basin and South East Corner bioregions it is likely to become extinct in nature in New South Wales unless the circumstances and factors threatening its survival cease to operate.

Dr Lesley Hughes
Chairperson
Scientific Committee

Proposed Gazettal date: 21/10/05

Exhibition period 21/10/05 - 16/12/05

References

Burges A, Drover, DP (1952) The rate of podzol development in sands of the Woy Woy district, N. S. W. Australian Journal of Botany1 , 83-95.

Keith DA (1996) Fire-driven mechanisms of extinction in vascular plants: a review of empirical and theoretical evidence in Australian vegetation. Proceedings of the Linnean Society of New South Wales116,  37-78.

Keith DA, Bedward M (1999). Vegetation of the South East Forest region, Eden, New South Wales. Cunninghamia6 , 1-218.

Mills K (2000) Rural lands study City of Shellharbour. Nature conservation study. Shellharbour City Council.

Tindall D, Pennay C, Tozer MG, Turner K, Keith DA (2004) 'Native vegetation map report series. No. 4. Araluen, Batemans Bay, Braidwood, Burragorang, Goulburn, Jervis Bay, Katoomba, Kiama, Moss Vale, Penrith, Port Hacking, Sydney, Taralga, Ulladulla, Wollongong.' NSW Department of Environment and Conservation and NSW Department of Infrastructure, Planning and Natural Resources, Sydney.

Thackway R, Creswell ID (1995) (eds) 'An interim biogeographic regionalisation of Australia: a framework for establishing the national system of reserves.' (Australian Nature Conservation Agency: Canberra).

Thomas V, Gellie N, Harrison T (2000) 'Forest ecosystem classification and mapping for the southern Comprehensive Regional Assessment.' NSW National Parks and Wildlife Service, Queanbeyan.