NSW Bitou Bush Threat Abatement Plan - Department of ...

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34 Threat Abatement Plan - Invasion of native plant communities by Chrysanthemoides monilifera 2. Littoral rainforests (including SEPP 26 and Sutherland Shire Littoral Rainforest) Littoral rainforests occur only on the coast and are found at locations in the NSW North Coast Bioregion, Sydney Basin Bioregion and South East Corner Bioregion (NSW SC 2004). Littoral rainforests are recognised as having high conservation significance because they contain elements of both subtropical and dry rainforests and a high diversity of plants and animals, including many rare and threatened species (Mills 1996; McDonald 1999). The plant species in this ecological community are predominantly rainforest species with evergreen mesic or coriaceous leaves, and vines may be a major component of the canopy, however, there is considerable floristic variation between stands (NSW SC 2004). Littoral rainforests also provide habitat for many migratory and nomadic animals. Littoral rainforests are very rare and occur in many small stands – less than a quarter of their original extent remains. In total, littoral rainforests comprise less than one percent of the total area of rainforest in New South Wales. Although a number of stands exist in reserves (e.g. 90 ha stand in Iluka NR), there are at least 130 stands of littoral rainforest of state significance which are not encompassed within a formal conservation reserve. These stands are small, mostly degraded remnants extending from the South Coast to the Tweed River, with a total area less than 100 ha (Mills 1996), and most have been gazetted under the State Environmental Planning Policy Number 26 (SEPP 26). The SEPP 26 gazettal includes a 100 m buffer around each remnant. Note that not all stands of this community have been included in mapping for SEPP 26, especially stands which are already protected by formal reserves. In 2004, littoral rainforests in the NSW North Coast, Sydney Basin and South East Corner bioregions were listed as an EEC under the TSC Act. While this listing replaces and incorporates the Sutherland Shire Littoral Rainforest listing under the TSC Act (NSW SC 1998c), it does not make the SEPP 26 classification defunct. The term littoral rainforest as used here encompasses those littoral rainforests listed under both the TSC Act and SEPP 26. Bitou bush poses a serious threat to littoral rainforest, especially in northern New South Wales. Over the last 10 years, land managers and/or community groups in New South Wales have commenced many littoral rainforest restoration programs. Many of these programs have involved general weed control, however control of bitou bush is often a low priority because it occurs primarily at the margins and other weeds are more prevalent within the core of the rainforest. 3. Kurnell Dune Forest (Sydney) Kurnell Dune Forest (KDF) is a low open sclerophyll forest community with a distinct mesophyll element. It is found on sand, often in association with areas of sclerophyll heath and scrub (NSW SC 1999b). The KDF community has been greatly reduced since European settlement and in 1999 was listed as an EEC under the TSC Act. Patches occur within the Sutherland Shire (including the Kurnell Peninsula and the City of Rockdale) on a range of public and private land. Threats are disturbance and weed invasion (including bitou bush), particularly on the Kurnell Peninsula. Since the early 1990s the former NPWS (now the Parks and Wildlife Division of DEC) has conducted extensive bitou bush control programs including aerial spraying, and involving contractors, NPWS staff and a number of volunteer groups. In 1998 Sutherland Shire Council began a major bitou bush control program on the Kurnell Peninsula. To date, bitou bush has been managed on the eastern margins of the KDF community, specifically in Charlotte Breen Reserve (Kurnell). Recently a joint bitou bush control program between Sutherland Shire Council and the Parks and Wildlife Division of DEC commenced in the Boat Harbour Reserve and adjacent areas. A detailed survey needs to be conducted of a patch of KDF reported from Towra Point NR, where a dense infestation of bitou bush occurs.
Threat Abatement Plan - Invasion of native plant communities by Chrysanthemoides monilifera 4. Coastal Banksia Woodland Coastal Banksia Woodland communities are an open forest to shrubland on deep sand soils usually in close proximity to the ocean. The ecological community comprises numerous small banksia tree species including coast banksia (Banksia integrifolia var. integrifolia), which is the most prolific species. Other dominant species include Casuarina glauca, Hibiscus tiliaceus, Acacia sophorae, Casuarina equisetifolia, Lophostemon confertus, Acacia melanoxylon, Glochidion spp., Callitris columellaris and Acacia aulacocarpa (Tweed Shire Council 2004). Bitou bush readily invades Coastal Banksia Woodland communities in New South Wales. 5. Themeda grasslands on sea cliffs and coastal headlands Themeda grasslands on sea cliffs and coastal headlands in New South Wales are described as a unique ecological community (see Adam et al. 1989). This ecological community is found in the NSW North Coast, Sydney Basin and South East Corner bioregions, on sea cliffs and coastal headlands. The structure of the community is typically closed tussock grassland, but may be open shrubland or open heath with a grassy matrix between the shrubs (NSW SC 2005). The community belongs to the Maritime Grasslands vegetation class of Keith (2004). Due to its highly restricted distribution, small patch size and ongoing threats to the community, it was recently listed as an EEC under the TSC Act (NSW SC 2005). The dominant species is Themeda triandra, but some suggest that it may be a separate headland form or subspecies (Dodkin pers. comm.). This ecological community also contains scattered shrubs in many stands, most frequently Pimelea linifolia, Banksia integrifolia and Westringia fruticosa. These and other woody species often have dwarf growth forms. Although a number of woody species are listed as part of the community, these are usually sparsely distributed and may be absent from some stands. Tussocks of Poa poiformis may be found in some stands of the community. A number of threatened species occur in some stands of the community, including Diuris byronensis (Synonym: Diuris sp. aff. Chrysantha), Pultenaea maritima, Rutidosus heterogama, Thesium australe (Cohn 2004) and Zieria prostrata (Hogbin 2001). The endangered population of the low growing form of Zieria smithii at Diggers Head is also found in this community. The community is the major habitat for a number of other species, including Chamaecrista maritima, Plectranthus cremnus and Stackhousia spathulata examined here. Invasion of bitou bush and other weeds is acknowledged as a major threat to the persistence of Themeda grasslands (NSW SC 2005). 6. Coastal sand wallum heath Coastal sand wallum heaths are a heath assemblage dominated by a shrub layer of wallum banksia (Banksia aemula), Leptospermum trinervium, Isopogon anemonifolius, and Ricinocarpus pinifolius to a height of 2 m. Wallum sand heaths are scattered along the NSW coast north from Sydney with some areas being exposed to intense disturbance from tourism and recreation. This disturbance can lead to erosion and dune destabilisation. Sand mining has destroyed some areas with many of these areas being invaded by bitou bush (Keith 2004). Coastal sand wallum heath is a known habitat for several threatened species including the grey-headed flying fox, black flying fox, eastern blossom bat and squirrel glider; all of which are identified in Chapter 5 as potentially at risk from bitou bush invasion. 7. Frontal dune vegetation complex The frontal dune vegetation complex ecological community occurs as a low to mid-high tussock grassland of variable crown cover, dominated by Spinifex sericeus, that occurs on the exposed 35
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