Brisbane Water National Park is a national park on the Central Coast of New South Wales, Australia. The national park is situated north of Sydney and southwest of Gosford. It consists the Brisbane Water and Mooney Mooney Creek waterways.
The National Park includes the Lion Island and the Spectagle Island near the Pacific Ocean. Brisbane Water National Park features fertile valleys which runs along the northern side of the Hawkesbury River towards Brisbane Water and the Pacific Ocean. The national park has an area of and is inhabited by the Darkinjung people.
Features
The park has many pleasant and interesting walks that can vary from mild to rugged. One walk that can be easily accessed via public transport, is the walk to Pindar Cave on the escarpment above the Wondabyne railway station, which is a request-stop on the Central Coast railway line. The Great North Walk, that leads from Sydney to Newcastle, passes through the park.
The national park is bounded to the south by the Hawkesbury River; to the west by part of the Pacific Highway, part of the M1 Pacific Motorway, and the Peats Ridge Road; with the latter also forming the northern boundary; and to the east by the Brisbane Water, the Central Coast railway line, and urban areas. The Hawkesbury River Railway Bridge, part of the Central Coast Highway, part of the Pacific Highway and part of the M1 Motorway bisect various sections of the national park. The park is a sanctuary for plant and animal communities to adapt and migrate in the face of climate change. The size and shape of the park should allow adjustment in the northwest and wouth for biological adjustment. The park is a system of reserves protecting the state's significant waterways of the lower Hawkesbury River, Broken Bay and Brisbane Water.
Biology and ecology
The park covers enough area to provide critical nesting and breeding sites for several species whose territories range over surrounding rural and urban areas. For many of these species the park provides the only secure available land for them to find seclusion from human impacts. For many of these plant and animal species the park is the only available habitat which provides the necessary resources for their survival such as tree hollows. The critically endangered communities listed in the EPBC act in the park are: Blue Gum High Forest in the Sydney Basin Bioregion, Littoral Rainforest in the New South Wales North Coast, Lowland Rainforest in the NSW North Coast and Sydney Basin Bioregions, Shale Sandstone Transition Forest in the Sydney Basin Bioregion, and Western Sydney Dry Rainforest in the Sydney Basin Bioregion. Only around 4.5% of the Blue Gum High Forest remains, now occurring in small remnants. It only occurs in areas where rainfall is high and soil fertility is good. For this reason it can only occur in small sections which are suitable for growth. Understorey species rely on bird and mammal species to distribute seeds and this community does not cope well in fire events. The Blue Gum High Forest is known to occur in Brisbane Water National Park and is now reliant on national park status as protection from habitat degradation, as well as good park management with regards to invasive species control and fire regimes.
Flora
A number of areas in Brisbane Water National Park contain rare and endangered plants. It is likely that these remnant populations demonstrate the ways that environmental conditions have changed in the past few thousand years. In some cases these rare species are remnants of populations that would have been extensive before widespread clearing took place for urban and agricultural use.
The vulnerable Camfield stringybarks (Eucalyptus camfieldii) range in NSW has contracted and is now only found in small numbers isolated mainly to nationals parks surrounding Sydney. The species is either a mallee-like shrub or a tree up to 9 metres bearing heart shaped leaves as a juvenile. Too frequent or not frequent enough wildfire activity is a threat to its survival, where frequent fires impact its ability to grow seed capsules and infrequent fires result in competition from taller vegetation.
The endangered Somersby mintbush (Prostanthera junonis) is only known to occur in the Somersby Plateau area in nine locations after having been previously present in a broader range. The bush grows low with most of the branches growing along the ground to a maximum height of around . Its flowers are pale mauve to almost white. Most of the remaining population are present in Brisbane Water National Park and face similar threats to Camfield's Stringybark which are: habitat degradation, invasive weed competition, and inappropriate fire regimes. The critically endangered regent honeyeater (Anthochaera Phrygia) has been sighted in the park. Regent honeyeater range has contracted significantly in recent times and they face a significantly high risk of extinction in the near future The regent honeyeater is a flagship species whose conservation benefits a wide variety of other threatened and vulnerable woodland fauna. Foraging non breeding flocks are recorded on the Central Coast every few years and rely on healthy woodland which is species rich for their survival.
Other migratory bird species known to visit the park are the white-throated needletail (Hirundapus caudacutus), The Caspian tern (Hydroprogne caspia), and the white-bellied sea-eagle (Haliaeetus leucogaster). The spotted tail quoll (Dasyurus maculatus) is in serious decline due to habitat loss, competition from predators, and poisoning from humans. The quoll occupies a large home range meaning they require a lot of space for foraging, and is therefore mainly restricted to large reserves and national parks. The species require suitable den sites which can be tree and log hollows, rock outcrops, and caves. Habitat fragmentation and degradation are severe impacts for this species as smaller parcels of fragmented land do not provide the necessary habitat, rainfall, nesting sites, and prey, which the spotted tail quoll relies on for survival. The squirrel glider and other glider species found in the park specifically rely on the shelter of tree hollows and on flowering Acacia and Banksia genus shrubs for food. Urban development, agriculture, and infrastructure is increasingly fragmenting the required habitat for these species
Environmental threats
thumb|Common fox (Vulpes vulpes)
Brisbane Water National Park is vulnerable to various environmental threats. Introduced invasive feral animals are of particular concern, this includes foxes (Vulpes vulpes), wild dogs (Canis familiaris), and cats (Felis catus). Wild dogs and cats are of particular concern due to the proximity of the park to areas of highly urbanised land use. This makes the wild dog and cat issue particularly prevalent. Cats and wild dogs are significant predators because they interact with fauna in a number of ways, for instance predation, outcompeting natives for resources, and transmitting disease. This impacts the native fauna as wild dogs generally prey on large and medium species such as wallabies and possums, and cats prey on medium and small prey including reptiles and small mammals. These pests can cause local extinctions and are a real threat to species which are already vulnerable or endangered. Eroding soils from degradation and increased transport of sediment from nearby runoff can transport sediments and nutrients which encourages weed growth. An example of the significance of weed invasion is the previously mentioned Blue Gum High Forest and Somersby mintbush (Prostanthera junonis) which are susceptible to weed invasion. Pest species displace natives and alter the ecosystem functions which creates ongoing implications such as altered fire patterns and changed nutrient cycling. The proximity of urban dwellings to the national park allows weed seeds to be easily introduced on a regular basis, which means regular maintenance and monitoring is required to ensure invasive species are kept in control. The biggest threat from invasive weeds is the degradation of biological diversity The areas surrounding the national park on plateaus was easily settled, therefore the remaining area originally reserved for parkland was limited to remnant areas on the plateau and areas of the catchments in Mooney Mooney, Patonga, and Mullet Creeks, because these areas remained inaccessible for settlement, they are generally harder for access. The locations of settlements mean the national park is hemmed in on two sides by development. The threats to the park caused by intensive agricultural, urban, and industrial development on the boundaries and headwaters make the management of the park difficult, and are increasing over time with continual development proposals such as those on the Kariong and Somersby plateaus which are in various catchment areas of the park.