Herbivory and environmental degradation caused by feral deer was listed as a KEY THREATENING PROCESS on Schedule 3 of the Threatened Species Conservation Act 1995 [17 December 2004].
Six species of deer (family Cervidae) have established feral populations in New South Wales (Wilson et al. 1992, Bentley 1995, Moriarty 2004a). These are Rusa Deer, Red Deer, Sambar Deer, Chital Deer, Hog Deer (Zimmermann 1780), and Fallow Deer.
At least nine threatened species or populations of plants are known to be eaten by deer (A. Moriarty, unpublished data): Acacia bynoeana, Persoonia hirsute, Eucalyptus camfieldii, Leucopogon exolasius, Melaleuca deanei, Prostanthera densa, Pultenaea aristate, Syzygium paniculatum, and Callitris endlicheri population on the Woronora Plateau.
Grazing and trampling by deer could alter the composition and structure of the following Endangered Ecological Communities: - Littoral Rainforest, O'Hares Creek Shale Forest, Sydney Freshwater Wetlands, Montane Peatlands and Swamps, River-Flat Eucalypt Forest on Coastal Floodplains and Swamp Sclerophyll Forest on Coastal Floodplains. Grazing and trampling by deer could alter the composition and structure of the habitats of threatened fauna, including: Southern Brown Bandicoot and Long-footed Potoroo.
All species extant in NSW have patchy distributions in forest and woodland in eastern New South Wales, with two species (Red and Fallow Deer) extending west of the Great Dividing Range (Wilson et al. 1992, Moriarty 2004a). Feral deer are known to occur in many conservation reserves, including Bouddi, Deua, Guy Fawkes River, Royal, Blue Mountains, Kosciuszko, Morton, South East Forests, Wadbilliga and Towarri National Parks; Dharawal, Illawarra Escarpment and Mount Canobolas State Conservation Areas and Dharawal, Karuah, Lake Innes, Macquarie, Sea Acres and Wallaroo Nature Reserves.