Following the industrialisation and urbanisation of the Kurnell Peninsula (see history) much of Kurnell's original ecology has been destroyed and today only remnants remain. This blog post presents an overview of these five remaining endangered ecological communities, each of which provides habitat for rare and fragile plant and animal species and are listed under the Threatened Species Conservation Act 1995. Adverse threats to the ecological character of Towra Point Nature Reserve and the surrounding catchment area include inappropriate recreation, pollution, mangrove encroachment, altered hydrological regimes urban and industrial development, weeds and pests. Predicted sea level rises as a result of climate change is another factor. Species listed in the Endangered Ecological Community occur within the terrestrial areas of Towra Point Nature Reserve and in Botany Bay National Park. There are also a number of Endangered Ecological Communities determined under the Threatened Species Conservation Act 1995 by the NSW Scientific Committee. Other plant and animal species in or around the Kurnell Peninsula and southern side of Botany Bay have been identified by the Threatened Species Conservation Act and include the Green and Golden Bell Frog and the Little Tern
1. The Coastal Saltmarshes
These are located in Towra Point and have been listed as an endangered ecological community. The Scientific Committee established by the Threatened Species Conservation Act is of the opinion that the Coastal Saltmarsh in the NSW North Coast, Sydney Basin and South East Corner Bioregions is likely to become extinct in nature in New South Wales unless the circumstances and factors threatening its survival cease to operate. Coastal Saltmarsh occurs in the intertidal zone on the shores of estuaries and lagoons that are permanently or intermittently open to the sea. It is frequently found as a zone on the landward side of mangrove stands. The saltmarsh habitat of Towra Point has adapted to occasional inundation from both freshwater and saltwater and provides an important foraging habit for migratory birds. The 157 hectares of saltmarsh at Towra Point are the biggest saltmarsh habitat in the Sydney region. It's an important part of the marine food web and provides roosting sites for wading birds. The main threats to the saltmarshes include mangrove encroachment, alteration of salinity and increasing nutrient levels resulting from the discharge of stormwater, dumping of rubbish, catchment runoff of nutrients and agricultural chemicals and weed invasion. The tidal mudflats of Towra Point are home to aquatic worms and invertebrates and are the preferred feeding and roosting areas for wading birds.
Coastal Saltmarsh provide habitat for a diverse invertebrate fauna, which includes both marine (crabs and molluscs) and terrestrial (insects and spiders) elements. During tidal flooding a number of fish species utilise saltmarsh habitats. Grazing by macropods may occur between tidal events. The mangrove invasion limits the use of saltmarshes by birds that would normally make use of this habitat and has been a factor in their decline. Saltmarshes have frequently been used for casual rubbish dumping and are at risk from waterborne pollution - including oil and chemical spills, both from shipping and road accidents, and catchment runoff of nutrients and agricultural chemicals. Global warming and increased relative sea level are likely to pose an increasing threat to the survival of many areas of Coastal Saltmarsh (Adam 2002, Hughes 2003).
Sources
Adam P (2002) Saltmarshes in a time of change. Environmental Conservation 29, 39-61.
Department of Environment and Conservation, Coastal Saltmarsh in the NSW North Coast, Sydney Basin and South East Corner Bioregions – profile http://www.threatenedspecies.environment.nsw.gov.au/tsprofile/profile.aspx?id=10866
Department of Environment and Conservation Coastal Saltmarsh in the NSW North Coast, Sydney Basin and South East Corner bioregions - endangered ecological community listing, NSW Scientific Committee Final Determination http://www.environment.nsw.gov.au/determinations/CoastalSaltmarshEndSpListing.htm
2. Kurnell Dune Forests
The Kurnell Dune Forest occurs in the Sutherland Shire and in the City of Rockdale (Leo Smith Reserve). Within Sutherland Shire the major occurrences are on the Kurnell Peninsula. The extent of the community has been reduced by clearing and development and remaining stands are separated. The large edge/area ratio of remaining stands makes them vulnerable to disturbance and weed invasion. Several stands are included in either NPWS estate or Council reserves. However, reservation itself does not prevent degradation from weed invasion and disturbance. Non reserved stands which include Calsil Dune may be at risk from development. Given the limited extent of the community the Scientific Committee is of the opinion that the Kurnell Dune Forest in Sutherland Shire and the City of Rockdale 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. The Scientific Committee, established by the Threatened Species Conservation Act, has made a Final Determination to list the Kurnell Dune Forest in the Sutherland Shire and the City of Rockdale as an Endangered Ecological Community.
The major threats to Kurnell Dune Forest include fragmentation and loss of habitat, particularly as a consequence of residential development and sand mining, degradation of habitat from rubbish dumping and Bitou Bush weed invasion. Disturbances associated with the installation and maintenance of utilities, inappropriate plantings in and around remnants, and the permitting of unrestricted access by people, horses, trail bikes, and recreational vehicles leading to physical damage and erosion. During the laying of pipelines for the upgrade of the Cronulla Sewage Treatment Plant, some Kurnell Dune Forest was damaged and cleared and work was halted for a period by the State Government.
Sources
Department of Climate Change and Water, Kurnell dune forest in the Sutherland Shire and the City of Rockdale - endangered ecological community listing, NSW Scientific Committee http://www.environment.nsw.gov.au/determinations/KurnellDuneForestSouthSydneyEndComListing.htm
Department of Environment and Conservation N.S.W, Kurnell Dune Forest in the Sutherland Shire and City of Rockdale – profile http://www.threatenedspecies.environment.nsw.gov.au/tsprofile/profile.aspx?id=10448
Sutherland Shire Environment Centre, The Kurnell Peninsula, Endangered Species http://www.ssec.org.au/our_environment/our_bioregion/kurnell/environment/endangered_species.htm
3. Littoral Rainforest
The Littoral rainforest is a closed canopy forest characterised by trees, shrubs and vines. It is distinct from open sclerophyll forests in the Sutherland Shire. Towra Point contains a few isolated remnants of the now endangered Sutherland Shire littoral rainforest. The rainforest supports the magenta bush cherry (Syzygium paniculatum) and tuckeroo (Cupaniopsis anarcardiodes). Littoral Rainforest occurs only on the coast and is found at locations in the NSW North Coast Bioregion, Sydney Basin Bioregion and South East Corner Bioregion. Littoral Rainforest is very rare and occurs in many small stands. In total, it comprises less than one percent of the total area of rainforest in NSW. Littoral Rainforest in the NSW North Coast, Sydney Basin and South East Corner Bioregions and Lowland Rainforest in the NSW North Coast and Sydney Basin Bioregions are listed as Endangered Ecological Communities under the NSW Threatened Species Conservation Act 1995 (NSW Scientific Committee 2004). The clearing of valley floor vegetation, including lowland rainforest and riparian gallery forest for agriculture, and clearing of coastal sand flats for development of residential and recreational areas, has almost certainly led to a reduction in available habitat, and a reduction in the size of remaining populations (DECC 2007). Populations such as the one at Towra Point situated near extreme high water mark, may be at risk from future sea level rise (Hughes 2003). Anthropogenic Climate Change is listed as a Key Threatening Process under the NSW Threatened Species Conservation Act 1995.
Sources
Department of Environment and Conservation N.S.W, Littoral Rainforest in the NSW North Coast, Sydney Basin and South East Corner Bioregions – profile, http://www.threatenedspecies.environment.nsw.gov.au/tsprofile/profile.aspx?id=10867
Department of Sustainability, Environment, Water, Population and Communities, ‘Threatened species & ecological communities’, http://www.environment.gov.au/biodiversity/threatened/index.html
Department of Climate Change and Water, ‘Syzygium paniculatum - endangered species listing’, http://www.environment.nsw.gov.au/determinations/syzygiumpaniculatumFD.htm
Hughes L (2003) Climate change and Australia: trends, projections and research directions. Austral Ecology 28: 423-443
For Part 2 click here
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