Designing a biodiversity index to assess east-west landscape linkage

The use of competitive (market-like) processes to identify preferred linkage zones across the bioregion is based on the assessment of which bids are most cost-effective. This can be achieved by comparing some summary index of the biodiversity benefits against the proposed costs for different options. A biodiversity index is required to assess landscape linkage options across the southern Desert Uplands taking into account both the biodiversity and landscape linkage values of possible vegetation connections across a bioregion. A Total Biodiversity Index is proposed that is a combination of Biodiversity Benefits Indexes for individual bid areas on properties and an overall Landscape Linkage Index. The version of the Biodiversity Benefits Index that is proposed for the assessment of individual property bid areas, builds on those developed in Victoria and New South Wales. This index covers the conservation significance, vegetation condition and landscape context for each individual property contribution. It is proposed that one site assessment per regional ecosystem (or groups of regional ecosystems) be undertaken per property bid area to ascertain vegetation condition. This site assessment should be indicative of the average condition of that vegetation type in the bid area and should be located with this purpose in mind. The bioregional biodiversity planning assessment will determine the conservation significance of an area. A modified version of the ‘Habitat Hectares’ approach for vegetation condition assessment as used in the southern states is recommended. The comprehensive approach that has been developed is consistent with many other assessment mechanisms and is suitable for use in a wide range of locations. In much of the Desert Uplands where the focus is on maintaining existing conditions, this level of detail may not be appropriate. In this situation, a simplified Biodiversity Benefits Index may be appropriate to expedite the assessment process.