The composition of the insect fauna of the Canberra region follows a transition broadly corresponding to temperature as influenced by altitude, and precipitation controlled largely, on the local scale, by altitude and topography. Thus the fauna of the crest of the Brindabella Range is different to that of the lowlands around Canberra. On a more restricted scale, the flora and vegetation of a locality can tell us much about the kinds of insects we can expect to find there.
The Murrumbidgee River where it leaves the ACT to enter the proposed Murrumbidgee - Ginninderra Gorges National Park is the lowest topographic point in the ACT, with a correspondingly warm climate. River oaks(Casuarina cunninghamiana lining the Murrumbidgee and the lower parts of its tributaries are host to insect species not found elsewhere, while on the surrounding slopes of the gorge, Burgan (Kunzea ericoides provides abundant nectar in summer for a host of species, some of them very flamboyant. Black cypress pine (Callitris endlicheri), one of only two native conifers locally, is commonly found scattered within the Burgan shrub land; it is the sole local host of a number of moth, beetle, sawfly and other species.
A second major habitat within the proposed National Park is the aquatic and riparian one. Dragonflies, caddis flies, stoneflies and numerous species of beetles and bugs breed only in freshwater. A proportion of these can utilise man-made reservoirs and dams, but many require permanent streams. The Murrumbidgee River is important as the major permanent lowland stream in the region. Fortunately, the Murrumbidgee River corridor within the ACT enjoys a level of nature conservation protection. The proposed National Park would provide a valuable extension of this protection into the warmer lower reaches of the river within our region, which are likely to carry insect faunal elements rare in, or absent from upstream parts (Kim Pullen, 2011).
(Kim Pullen is with the CSIRO Division of Sustainable Ecosystems, Canberra. He has been collecting and studying insects in the Canberra Region for 45 years. )