94 Paragraph 2 of the Final Determination lists the assemblage of species that characterise BGHF in the Sydney Basin Bioregion. Paragraphs 3 and 4 of the Final Determination provide a general description of the community.
3. The total species list of the community is considerably larger than that given above, with many species present in only 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 condition and by its disturbance (including fire) history. The number of species, and the above ground relative abundance of species will change with time since fire, and may also change in response to changes in fire regime (including changes in fire frequency). 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 of vascular plant species; 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. Blue Gum High Forest is dominated by a tall canopy of eucalypts that may exceed 30 m in height. Its understorey is typically multi-layered with a midstorey of mesophyllous shrubs and small trees and a diverse ground layer of herbs, ferns and some grasses. Most stands of the community are in a state of regrowth after past clearing or logging activities, and consequently trees may be shorter, less dense or more dense than less disturbed stands. Blue Gum High Forest is dominated by either Eucalyptus pilularis (Blackbutt) or E. saligna (Sydney Blue Gum). Angophora costata (Smooth-barked Apple) is frequently observed in remnants close to the shale/sandstone boundary, but also occurs infrequently on deep shale soils, as does A. floribunda (Rough-barked Apple). Eucalyptus paniculata (Grey Ironbark) is typically found on upper slopes. A relatively diverse stratum of small trees is usually present, and includes Pittosporum undulatum (Sweet Pittosporum), Elaeocarpus reticulatus (Blueberry Ash) and Allocasuarina torulosa (Forest Oak). Shrub species are typically mesophyllous, such as Breynia oblongifolia (Coffee Bush), Pittosporum revolutum , (Yellow Pittosporum), Clerodendrum tomentosum , Notelaea longifolia forma longifolia (Large Mock-olive), Maytenus sylvestris (Narrow-leaved Orange Bark), Polyscias sambucifolia subsp. A (Elderberry Panax) and Rapanea variabilis (Muttonwood). Mesophyllous species are generally more common in gullies associated with both shale and volcanic soils than slopes and ridgetops. Sclerophyllous species such as Persoonia linearis (Narrow-leaved Geebung) and Leucopogon juniperinum (Prickly Bearded-heath) occur more frequently closer to the shale/sandstone boundary. The ground stratum is often dense and contains a mixture of herb, grass and fern species including Adiantum aethiopicum, Entolasia marginata (Bordered Panic), Lomandra longifolia (Spiny-headed Matrush), Calochlaena dubia (Common Groundfern), Dianella caerulea (Blue Flax Lily), Pseuderanthemum variabile (Pastel Flower) and Oplismenus imbecillis. Vine species are also frequently present, in particular Tylophora barbata (Bearded Tylophora), Eustrephus latifolia , (Wombat Berry), Clematis aristata (Old Man's Beard) and Pandorea pandorana (Wonga Wonga Vine).
95 Paragraphs 9, 10 and 11 describe the extent and the changes that have occurred.
9. Blue Gum High Forest has a very highly restricted geographic distribution, and is currently estimated to cover an extant area of less than 200 ha (Tozer 2003). The distribution comprises a series of small remnant patches, the largest of which is less than 20ha. Highly modified relics of the community also persist as small clumps of trees without a native understorey. All remnants of the community are now surrounded by urban development. Consequently, the distribution of Blue Gum High Forest is severely fragmented. Fragmentation of habitat contributes to a very large reduction in the ecological function of the community.
10. Prior to European settlement, about 200 years ago, Blue Gum High Forest is estimated to have covered an area of approximately 3700 ha (Tozer 2003). Its current extent amounts to less than 5% of this original distribution. The dominant eucalypts of the community live for several hundred years. Blue Gum High Forest has therefore undergone a very large reduction in its geographic distribution within a time span appropriate to the life cycle and habitat characteristics of its component species. Small-scale clearing associated with residential subdivision, road upgrading, extension and maintenance of service easements, etc. pose a threat of ongoing decline in the extent of the community. Clearing of native vegetation is listed as a Key Threatening Process under the Threatened Species Conservation Act 1995.
11. Changes in structure of Blue Gum High Forest have occurred as a consequence of the extensive removal of large old trees. A number of stands of Blue Gum Forests have highly modified understories, in which the native woody component has been largely replaced by woody exotic species or by increased abundance of native and exotic grasses. Continued underscrubbing, frequent burning and mowing may maintain the understorey in an artificially open state and prevent recruitment of species with the community. The loss of large trees removes essential habitat for a range of tree-dependent fauna (Gibbons and Lindenmeyer 1996). The reduction of understorey complexity, through the reduction of native shrub cover, degrades habitat for a range of bird and mammal species (Catling 1991). These processes contribute to a very large reduction in the ecological function of the community.