Advances in the identification and assessment of ecologically significant habitats in two areas of contrasting biodiversity loss in New Zealand

The Resource Management Act 1991 places obligations on local authorities to protect and maintain indigenous biodiversity on land in private tenure. However, how this should be done is not explicitly prescribed. Authorities are guided by a variety of means (e.g. ecological guidance and case law), and implement their responsibilities to varying degrees and with inconsistent success. The protection of indigenous biodiversity on private land is a challenging and contentious issue. This paper reports on two different approaches for the identification and assessment of significant habitats that were recently validated by Court decisions in two regions of contrasting biodiversity loss in New Zealand: Manawatu-Wanganui and the West Coast. The rigorous semi-quantitative desktop methodology used in Horizons Regional Council’s resource management plan included a predictive model to compile a schedule of habitat types in the Manawatu-Wanganui Region, coupled with significance criteria to facilitate regulatory protection of significant habitat. This was the first time in New Zealand a region-wide habitat type approach had been undertaken and was subsequently accepted by the Environment Court. The methodology for identifying significant wetland areas in the West Coast Regional Council’s Land and Water Plan used a more traditional approach, employing schedules of mapped sites selected through applying a set of significance criteria. The Environment Court also endorsed this approach but recognised the need for more rigorous criteria. A caucus of experts was directed to improve the weak set of criteria initially proposed. The revised significance criteria now sit in the plan and have also been adapted for use by other regions (e.g. Canterbury). In both regions, the Environment Court rejected the use of site condition as a prerequisite for determining significance. This was also supported by the High Court in the West Coast case. These court decisions represent landmark case law, which advance the national debate on the application of significance criteria.