As Manager of the Comprehensive Regional Assessments (CRA)between 1996 and 2000, I coordinated and managed several large biodiversity assessments as part of the Environment & Heritage component of the Eden and Southern CRA Regions.The CRAs provided the scientific basis on which the State and Commonwealth Governments could create a Comprehensive, Adequate, and Representative (CAR) system on public land. At the same time the CRA process was meant to set up systems of ecologically sustainable forest management (ESFM) on all public land tenures, including State Forests, NPWS and Crown Land Reserves.

As part of the Southern CRA, I designed and implemented a vegetation mapping proposal for over 5,500,000 hectares of land of which 3,400,000 hectares was forested land. The mapping of vegetation types became the basis for mapping forest and non-forest ecosystems in that region. The derivation and mapping of forest ecosystems was identified as a major source of information to assess comprehensiveness and representativeness of forests in the Southern Regional Forest Agreement (RFA).

Based on the JANIS criteria (JANIS 1997), forest ecosystems were intended to act as broad surrogates for biodiversity within the Southern CRA Region. To meet the JANIS criteria, the classification of forest ecosystems had to meet the following criteria:

• Represent the full range of biodiversity;
• Be defined in terms of floristic composition in combination with substrate and position within the landscape;
• Be recognisable in the field;
• Be mapped at a practicable scale of at least 1:100,000; and
• Have their pre-1750 distribution modelled or mapped. (JANIS 1997).

The project objective was to prepare maps of pre-1750 and extant forest ecosystems over the Southern CRA Region to enable an assessment of the extent of reservation of forest ecosystems within conservation reserves.

The region was divided into three sub-regions to facilitate the mapping of vegetation as well as conform to regions to be negotiated in the Regional Forest Agreement negotiations. These regions became known as the South Coast, Western and Northern Subregions.

Forest ecosystem classification and mapping in the Southern CRA Region followed an approach developed by the Vegetation Mapping Group in the Southern CRA Unit, after exploration of a number of options which included:

1. Generalised additive modelling (GAM) of individual canopy plant species, then classified and mapped into forest ecosystem types - based on Mike Austin's approach used in the Interim Forest Assessment (IAP)
2. Generalised additive modelling (GAM) of grouped canopy plant species, then classified and mapped into forest ecosystem types
3. Classification of Vegetation using PATN software, and then mapping using the NPWS's Albero software
4. Classification of Vegetation using PATN software, and then mapping using expert mapping of forest ecosystems using a hybrid approach of mapping

Because of the availability of API mapping data across the region, the simplicity of mapping using expert knowledge, and the short time available to complete the vegetation mapping work, option 4 was chosen.

• derivation of a forest ecosystem classification from PATN analysis of full floristic plot data;
• allocation of validated API polygons to the classified forest ecosystem types on extant forest land;
• map pre-1750 extent of cleared forest ecosystems using one of two approaches:
  • expert allocation of soil landscapes to classified forest ecosystem types, using expert knowledge and classified site data, allocated to forest ecosystem types; and/or
• predictive Generalised Additive Modelling (GAM) using abiotic variables and soils information to extend the vegetation mapping across cleared land.

During all phases of the project, issues of classification and vegetation mapping were referred to an expert review group comprising four expert botanists all of whom were familiar and knowledgeable of the area. The expert review group was made up of one expert each from NPWS and SFNSW, as well as two independents. A seam-less vegetation coverage across the Southern CRA Region was derived by expert integration of the API mapping on extant forest land and mapping previous forest types on cleared forest land using the above modelling techniques.

Approximately 200 ecosystems were classified for the Southern CRA region, adjoining Commonwealth territories and 20km Eden buffer. One hundred and eighty ecosystems were mapped in the Southern CRA Region, of which 137 were eucalypt-dominated forest or woodland ecosystems, 11 were rainforest and 32 were terrestrial non-eucalypt vegetation. Detailed descriptions of each of these ecosystems are provided in this report. They represent a preliminary set of forest ecosystems, resulting from the classification and mapping carried out during the CRA.

Future work could involve further survey and more detailed mapping, which may result in changes to the classification and mapping of forest ecosystems. This hybrid approach was a successful marriage of an ecological classification applied to API mapping categories, delineated as part of the CRAFTI aerial photo-interpretation project. A scientific paper is currently being written describing the classification and mapping process in more detail.

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