What is biodiversity? Biodiversity is the variety of life and its interactions – it includes plants, animals, fungi and micro-organisms, the genetic information they contain and the ecosystems that they form in either terrestrial, marine, or aquatic environments. In short, biodiversity is life on Earth.
Why is biodiversity important? There are numerous ecosystem services provided by biodiversity, such as the pollination of crops, the provision of medicines, food and clothing, and the support systems we need to sustain human life. Biodiversity also contributes to the fulfilment of people’s cultural, spiritual, and intellectual needs.
How can biodiversity be characterised? Biodiversity can be chara
cterised by bioregions –these are broad biophysical featuresthat link flora and fauna assemblages and processes (Thackway and Cresswell, 1995). Bioregions are a means of simplifying and describing complex biological patterns and interactions. The Hunter, Central and Lower North Coast region of NSW straddles five bioregions: namely:
Sydney Basin: Mesozoic sandstones and shales; dissected plateaus; forests, woodlands and heaths; skeletal soils, sands and podzolics.
NSW North Coast: Humid; hills, coastal plains and sand dunes; Eucalyptus - Lophostemon confertus tall open forests, Eucalyptus open forests and woodlands, sub-tropical rainforest often with Araucaria cunninghamii, Melaleuca quinquenervia, wetlands, and heaths.
Brigalow Belt South: Predominantly Jurassic and younger deposits of the Great Artesian Basin and Tertiary deposits with elevated basalt flows. Subhumid Eucalyptus woodlands and open forests of ironbarks, poplar box, spotted gum (E. maculata), cypress pine (Callitris glaucophylla), Bloodwoods (eg. E. trachyphloia, E. hendersonii) brigalow-belah forests (E. harpophylla, Casuarina cristata) and semi-evergreen vine thicket.
New England Tableland: Elevated plateau of hills and plains on Palaeozoic sediments, granites and basalts; dominated by stringy bark/peppermint/box species, including E. caliginosa, E. nova-anglica, E. melliodora and E. blakelyi.
The vast majority of the Hunter, Central and Lower North Coast region occurs within three of these bioregions, namely the North Coast (50%), the Sydney Basin (39%), and to a lesser extent the Brigalow Belt South (10%).
Other broad biogeographic regions have been defined and delineated in order to better understand and characterise the occurrence and distribution of plant and animal species. For example, the NSW North Coast occurs within the Macleay-McPherson Overlap Zone, an area of exceptionally high biodiversity where the northern Torresian and southern Bassian faunas and floras of Australia meet and overlap – it is considered to have the richest diversity in Australia of birds, bats, amphibians and snakes.
Another example is the ecogeographic floristic divisions of Harden (1990). The Hunter, Central and Lower North Coast straddles two main divisions, the Coastal Division and Tablelands Division, and within these, there are four botanical subdivisions, namely:
The North Coast extends from the Queensland border to Lake Macquarie and is largely subtropical. Rainforests at one time were characteristic of the alluvial flats and rich basaltic soils, although these have now largely been destroyed to make way for agriculture. The richer loamy soils support tall eucalypt forests, but there are also stretches of poor sandy or stony soils and tidal flats with stunted forest, heath or mangroves.
The Central Coast covers the area between Lake Macquarie and the Shoalhaven River. Rainforests of relatively low species diversity occur in the moister or more sheltered sites and eucalypt forests are widespread. Areas of nutrient-poor sandstone, eg. Hawkesbury Sandstone, support a characteristic hard-leaved shrubby vegetation of many species.
The Northern Tablelands extends south from the Queensland border to the northern boundary of the Hunter Valley. The plateau region is covered with dry sclerophyll forest or more open grassy woodland dominated by species of eucalypt of moderate size although some higher altitude areas support tall wet sclerophyll forest and cool temperate rainforest.
The Central Western Slopes includes hilly, undulating and plains country comprising important agricultural, pastoral and forest areas. Lighter sandy and stone soils support dry sclerophyll forest or sometimes stunted shrubs. Soils of intermediate loamy texture were once occupied by tall woodland of eucalypt or Cypress pine, whilst heavier black soils often supported grassy woodland. These areas have now been extensively cleared.
What vegetation communities occur in the Hunter region? A vegetation community map is currently being prepared for the Hunter, Central and Lower North Coast region (check our Ongoing Activities). Until this map is available, the vegetation of this region can be broadly described by the vegetation formations that occur (a summary can be found here). These formations include: sub-tropical rainforest, warm-temperate rainforest; cool-temperate rainforest, dry rainforest, mangrove forest, tall open forest, open forest and woodland, heath, grassland, sedgeland, and wetland.
How many species are there in the Hunter region? There are approximately 3497 vascular plant species and 711 fauna species that occur in the Hunter, Central and Lower North Coast region of NSW (source: DEC Atlas Data). This number continues to grow as we learn more about the regions biota. Of those species that are known to occur in the region, there are 150 that are listed as vulnerable or endangered on the Threatened Species Conservation Act 1995. These species include 91 plant species, 21 bird species, 19 mammal species, 12 amphibian species, 4 reptile species, 2 insect species and 1 gastropod. You can download a list of these TSC-listed species here.
How can I find out more? You can obtain more detailed information about the regions flora and fauna from the Australian Faunal Directory, the Hunter Region Botanic Gardens, and the NSW ATLAS.
