Some Examples of Biodiversity Values in the Hunter Region Botanic Gardens Site

Ecosystem Diversity

The ecosystems of the Gardens Site include aquatic, terrestial and aboral habitats, and within each of these there are a number of different niches, e.g. in the aboral habitats bark and foliage niches may be partitioned, as may the tree hollows, branches and leaves.

The animal communities which occupy these different habitats and niches are also varied. Ants and non-flying insects as well as fungi occupy the ground litter. The same ants may also forage the tree foliage, but here there is a different suite of insects, mostly flying insects and their lava and different fungi; also the energy and nutrient cycling which takes place in these two niches is quite different.

A further example of ecosystem diversity occurs between the northern and southern wetlands. There is quite a different suite of water plants in each of these wetlands. The southern wetland is dominated by the Spikerush Eleocharis sphacelata with Gahnia clarkei and Baloskion tetraphyllum at the edges, while the northern wetland has a much greater diversity of plants, including Swamp Mahogany (Eucalyptus robusta) trees, shrubs of Callistemon citrinus, Banksia robur and Leptospermum juniperinus, the Swordgrass Ghania clarkei and ferns, and G. sieberi and several smaller water plants in the deeper water.

Species Diversity

The Garden's 143 hectare site contains some 182 indigenous plant species in 124 genera in 50 families, inhabitated by 86 species of birds in 73 genera in 36 families, 14 mammals in 13 genera, 14 frogs in 4 genera, 9 reptiles and 20 butterflies in 19 genera. This amounts to a large taxonomic species diversity as there is a reasonably large number of higher "taxa" (families, genera) present.

It is not likely that any of these species populations on the Site are discrete, except perhaps for some invertebrate species which have not been studied, and the ecological role of the species populations in the functioning of ecosystem processes also have not been studied.

Genetic Diversity

As an example of genetic diversity in the Gardens Site, in the usually pink flowering Tetratheca ericifolia population there occurs a few individuals with pure white flowers suggesting that on occasions two plants posessing the recessive "white flower" gene are crossed, producing a white flowered offspring. Such occurrences suggest diversity in the genetic makeup of the Tetratheca population.