[2] The low, undulating terrain of the reserve supports remnants of two threatened ecological communities – Natural Temperate Grassland and grassy Box-Gum Woodland.

[5] In 2004 The NSW Government gazetted a larger area of circa 64 hectares (160 acres) southern addition to the reserve – separate to and 0.275 metres (10.8 in) south of the existing northern section.

This newer area, previously managed by the NSW Department of Housing, is bound by Lanyon Drive to the east, Hoover Road to the north and the Queanbeyan-Michelago tourist railway line to the west.

[9] Since European settlement in the 1830s the distribution and condition of Natural Temperate Grassland has declined, initially due to extensive use for pastoral and agricultural activities and more recently as a result of a wide range of disturbances including grazing, application of fertilisers, introduction of exotic weed species, changed burning patterns, soil disturbance, changed drainage patterns, clearing for agriculture, plantation forestry, urban infrastructure and rural residential development.

[9] As a consequence, in 2000 Natural Temperate Grassland of the Southern Tablelands of NSW and the Australian Capital Territory was listed as Endangered under the Commonwealth Environment Protection and Biodiversity Conservation Act 1999.

The remnant community at Queanbeyan Nature Reserve has been classified as Wallaby-grass – Tall Speargrass – Common Everlastings Tussock Grassland of the South Eastern Highlands bioregion.

tricolor, Blue Devil Eryngium ovinum, Leafy Daisy Brachycome rigidula, Tufted Bluebell Wahlenbergia communis, and Lemon Beautyheads Calocephalus citreus.

[citation needed] Among weeds recorded are St John's Wort Hypericum perforatum, Serrated Tussock Nassella trichotoma, African Lovegrass Eragrostis curvula, Phalaris Phalaris aquatica, Cocksfoot Dactylis glomerata, Sweet Briar Rosa rubiginosa, Tree Lucerne Tagastaste sp., Paterson's curse Echium plantagineum, Monterey Pine Pinus radiata and a variety of thistles.

The groundcover is characterised by native grasses and a high diversity of herbs, while understorey shrubs are generally sparse or absent, though they may be locally common.

[12][16] Since European settlement habitat for the species has been lost, degraded or fragmented as a result of activities such as grazing, cropping, residential and other developments, invasion by weeds and changes to natural fire regimes.

[17][18] Golden Sun Moth occurs in Natural Temperate Grasslands and grassy Box-Gum Woodlands, where the groundcover is dominated by Wallaby Grasses Austrodanthonia spp.

Male Golden Sun Moths will not fly greater than 100m away from areas of suitable habitat, therefore populations separated by more than 200m can be considered effectively isolated.

[20] The loss and degradation of Natural Temperate Grassland and Box-Gum Woodland (as described above) throughout the original range of Golden Sun Moth has resulted in a significant reduction of suitable habitat.