Environmental issues

Pests and weeds

Herbivory and land degradation caused by feral deer as a key threatening process - an overview

The NSW Scientific Committee, the independent body of scientists responsible for listings under the Threatened Species Conservation Act 1995, has made a final determination to list "Herbivory and land degradation caused by feral deer" as a key threatening process.

More information


Why have feral deer been listed as a key threatening process?

The Scientific Committee is concerned about the impact of feral deer on biodiversity - particularly through:

  • Herbivory. Feral deer are herbivorous. They eat native plants, and can have a major impact on threatened plant species, populations and ecological communities.
  • Land degradation. Feral deer can damage the habitats of native animals, including threatened animal species which rely on these habitats to survive.

Feral deer can cause native species and plant communities to decline in particular areas, to the extent that they become endangered with extinction.

How does "herbivory and land degradation caused by feral deer" affect biodiversity?

The Scientific Committee has identified a number of threatened plant species and ecological communities that are affected by herbivory and land degradation caused by feral deer. Here are some examples:

  • Research on the impacts of feral deer in Royal National Park by the University of Western Sydney has shown that the endangered Sutherland Shire littoral rainforest has 70 per cent less understorey plant species at locations of high deer density, compared to low deer density locations.
  • In other research, the University of Wollongong has shown that deer have major impacts on endangered Sydney freshwater wetland communities in Royal National Park. As an example of the impacts deer are having on the wetland, 75 per cent of the stems and foliage of the threatened plant species, Syzygium paniculatum, was removed by deer. S. paniculatum is a rare plant species restricted to littoral rainforests.
  • Deer populations around Port Macquarie have been implicated in the trampling and browsing of rare littoral rainforest fragments. In particular, deer have had a negative impact on the threatened plant species: Sophora tomentosa, Hibiscus tiliaceus, Cynanchum elegans, Acronychia littoralis.
  • Feral deer populations are also increasing in the rare temperate and sub-tropical Illawarra rainforest. The deer have adversely affected threatened species such as Irenepharsus trypherus and Daphnandra species C.
  • Feral deer in Oxley Wild Rivers National Park, east of Armidale, have also been implicated in trampling and browsing of a number of threatened species. These include Thesium australe, Grevillea beadleana, Hibbertia hermanniifolia, Ozothamnus adnatus and Ricinocarpus speciosus.

What species of deer does this determination include?

In this listing, the Scientific Committee has included all six deer species known to have formed viable feral populations in Australia:

  • fallow deer
  • red deer
  • sambar deer
  • chital deer
  • rusa deer
  • hog deer.

How will this key threatening process be managed?

The Department of Environment and Conservation will be required to develop strategies for managing the threat. Consideration will be given to finding an approach that provides an effective way to ensure strategic allocation of resources, and provides for coordinated integration of existing or new programs.

In developing management strategies, the Department of Environment and Conservation will consider whether the preparation of a threat abatement plan is the most efficient and effective way to abate the threat, or whether other approaches would be more appropriate.

Management of the feral animal threats generally focuses on five objectives:

  • targeting control programs at the species or sites where the pest's impacts are likely to be greatest
  • developing guidelines that maximise the effectiveness of control programs while minimising the harm caused by the control measures on non-pest species
  • setting up monitoring programs to demonstrate the harmful impacts of the pest species and to measure the effectiveness of the pest control programs
  • identifying knowledge gaps and developing research proposals where information is lacking
  • increasing community education and involvement in controlling the pest species.

The strategies adopted to manage the threat will focus on similar objectives.

What impact does listing have on the operation of the Game and Feral Animal Control Act?

Deer are listed as a game animal under the Game and Feral Animal Control Act 2002. The Game and Feral Animal Control Act 2002 promotes responsible and orderly hunting of game animals, including deer. It also specifies conditions for the hunting of game animals.

The Threatened Species Conservation Act 1995(TSC Act) aims to manage processes that threaten the survival or evolutionary development of threatened species, populations and ecological communities. It is under this Act that the process of 'herbivory and land degradation caused by feral deer' has been recognised as a key threatening process.

It is possible to have the deer listed as a game animal under the Game Act at the same time as having 'herbivory and land degradation caused by feral deer' listed under the TSC Act. The two regimes are not mutually exclusive.

Will hunters continue to have hunting access to deer on private and public lands?

Yes, lands prescribed for the hunting of deer species under the Game and Feral Animal Control Act 2002 would not be affected. If the strategies identify areas of private land as priority sites for feral deer control, the landowners would be encouraged to control the deer, to protect threatened biodiversity on their land. Should the landowner wish to be involved, hunters could be asked to help control the deer at those sites. A similar approach could be adopted if priority sites are identified on public lands used by hunters.

Will deer farmers be affected by the listing?

No. The listing is for feral deer, not farmed deer.

More information


The format and structure of this publication may have been adapted for web delivery.

Page last updated: 26 February 2011