Image of Motorbike Frog in water
A motorbike frog from Western Australia's
south-west. Photo – Rebecca Kay

Biological diversity or biodiversity is the variety of all life forms on earth - the different plants, animals and micro-organisms, their genes, and the ecosystems of which they are a part, from the smallest one-cell microbe to the ancient giant tuart forest.

Biodiversity is important

Australia is home to between 600,000 and 700,000 species. About 84 per cent of our plants and mammals, and 45 per cent of our birds are only found in Australia.

Western Australia is home to many of these plants and animals. The state's south-west, in particular, has some of the richest diversity of plants and animals on earth.

Biodiversity in forests is protected by measures such as keeping physical corridors or links between habitats, and maintaining ecological processes such as decomposition and nutrient cycling.

We also need to restore the environment by protecting threatened species, and tackling threats such as feral animals, weeds and Phytophthora dieback.


To maintain biodiversity, we need to create a network of protected areas (reserves) of forest communities, individual species and genetic diversity within species. These reserves also protect habitat, evolutionary processes and systems that support ecological processes.

More than a million hectares of Western Australia's south-west native forest are in national parks, conservation parks, nature reserves and other reserves.

In addition, a network of informal reserves exists across other areas of State forest where activities such as wood and mineral production and forest recreation are permitted.

Creating these reserves involves identifying and protecting special zones and corridors in these areas, such as along streams and roads, and around wetlands, heaths, woodlands, and rock outcrops. This ensures that multiple-use forests can still maintain a rich collection of plants and animals that further extends the conservation of biodiversity in our forests.

Old‑growth forests

Old‑growth forest is ecologically mature forest where the effects of unnatural disturbance are now negligible.

Areas of old-growth forest were initially mapped for the Regional Forest Agreement (RFA) through the Comprehensive Regional Assessment process undertaken to prepare Western Australia’s RFA.

All old-growth forests in the south west have been protected from timber harvesting since 2001. Over 334,000 hectares of old-growth forest has been identified, with around 93 per cent protected in existing or proposed national parks, conservation parks or nature reserves. The remaining 7 per cent of mapped old-growth forest is protected through the establishment of informal reserves under the Forest Management Plan 2014-2023.

The current location and extent of old-growth forests is depicted in the following map, which is updated annually, and also identifies any changes in the extent of old-growth forest status.

pdfMap of old-growth forests February 20205.2 MB

Nominating an area of previously unmapped old‑growth forest

Dryandra moth Carthaea saturnioides 
Dryandra moth (Carthaea saturnioides). 
Photo – Janet Farr/DBCA

Although much work has been done to map all known areas old-growth forest, new areas are still being found because steps are taken to identify and protect any unmapped old-growth forest prior to disturbance operations. The community also has an opportunity to nominate areas of forest which may meet the criteria to be recognised as old-growth forest.

To nominate an area of forest that you believe may contain previously unmapped old-growth forest a public nomination form should be filled out and submitted to the Department (submission details are listed on the form). Please ensure all the details specified in the form are completed to ensure that processing commences as quickly as possible on receiving your nomination.

pdfPublic nomination form for the review of old-growth forest status120.42 KB

Following acceptance of the nomination an assessment of the area is conducted, and should additional old-growth forest be identified it will be added to the estate. Reports on public nominations to review the status of old-growth forest are listed below.

From 2005 to April 2017 the Conservation and Parks Commission (previously Conservation Commission of Western Australia) assessed areas of forest nominated by the community that may have met the criteria to be classified as old-growth forest. The findings and reports for this time can be viewed on the Conservation and Parks Commission website.

Public nominations

Fauna habitat zones

Fauna (animal) habitat zones are a network of areas across the forest landscape excluded from timber harvesting.

They provide a refuge for animals vulnerable to disturbance and, in the medium term, as a source of animals that can return to live in harvested areas as they regenerate.

Fauna habitat zones help meet the Forest Management Plan objective of ensuring that biodiversity recovers between one timber harvest and the next.

The fauna habitat zones are carefully selected to include a broad range of soil and landform types similar to those in the existing formal conservation reserve system. This helps establish and maintain a diverse range of habitats, and several stages of growth and regeneration.

Selection and managing fauna habitat zones are guided by:

  • Guidelines for the Selection of Fauna Habitat Zones (2017)
  • Guidelines for Protection of the Values of Informal Reserves and Fauna Habitat Zones (2009).

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Mainland quokka
Mainland quokka in the forest. 
Photo – DBCA

Forest plants and animals

Western Australia's south-west forests contain a unique and diverse range of plants and animals.

The Department of Parks and Wildlife also produces a series of Bush Books, available through our online shop.

The books include a range dedicated to the south west, covering a variety of topics such as butterflies, trees, mammals, fungi, common and rare birds, bush tucker, and orchids.