Subtropical-temperate forested wetlands of coastal south-eastern Australia - an analysis of vegetation data to support ecosystem risk assessment at regional, national and global scales

Context. Forested wetlands occurring on fluvial sediments are among the most threatened ecosystems in south-east Australia. The first quantitative diagnosis of forested wetland types in NSW was completed in 2005. Since then, there has been a three-fold increase in survey data on coastal floodplains, vegetation classification systems have been developed in New South Wales, Queensland and Victoria, and methods for the assessment of ecosystem conservation risks have been adopted by the International Union for the Conservation of Nature (IUCN). Aims. To ensure an evidence base that can support conservation decisions and national conservation assessments, there is a need to review and update the classification of forested wetlands and integrate classification schemes across jurisdictions. Methods. We evaluated the efficacy of a multi-stage clustering strategy, applied to data from different sources with largely unknown methodological idiosyncrasies, to retrieve ecologically meaningful clusters. We assessed the veracity and robustness of the 2005 classification of forest wetlands as a framework for national risk assessments over an expanded range. Key results. We derived a quantitative, cross-jurisdictional classification of forested wetlands based on a synthesis of 5173 plot samples drawn from three states and identified the status of our units in relation to IUCN's Global Ecosystem Typology. Conclusions. Our analyses support the retention of the five legacy types which are the basis for threatened ecosystem listings under the NSW Biodiversity Conservation Act 2016 and Commonwealth Environment Protection and Biodiversity Conservation Act 1999.