remaining species groups were considered to be strongly influenced by climate and geomorphology and were considered referential to IBRA bioregions. 1C Diversity of aquatic ecosystem vegetation types (Queensland only) Metrics: • number of aquatic ecosystem vegetation types within an assessment unit (referential to IBRA region). Prioritisation based on higher biological organisation levels, such as vegetation communities, can help overcome some of the shortfalls associated with sample bias in species-level data by using data at a scale for which uniform information is available across the landscape (Maddock & Du Plessis 1999). Conservation of vegetation communities is likely to benefit species indirectly (including known ones) as well as capturing diversity in function and natural processes (Noss & Harris 1986). A 200 m buffer surrounding the areas used to delineate the riverine typology and wetland typology was used to identify the ‘aquatic ecosystem’ vegetation. This data was sourced from the Remnant Ecosystem Mapping v6b. Queensland was the only jurisdiction with maps of aquatic ecosystem vegetation types (from mapped regional ecosystems) and able to apply this attribute. Criterion 2: Distinctiveness: The asset is a rare/threatened or unusual aquatic ecosystem; and/or supports rare/threatened species/communities and/or exhibits rare or unusual geomorphological or hydrological features/processes and/or environmental conditions, and is likely to support unusual assemblages of species adapted to these conditions. 2A Threatened species Metrics: • accumulated scores based on the presence of aquatic ecosystem-dependent threatened species (referential to the LEB)—a scoring system was Threatened species (and communities) are a common feature in the identification of high ecological value ecosystems (terrestrial and aquatic) and feature in most international schemes e.g. Ramsar Convention on Wetlands, World Heritage Convention, International Union for Conservation of Nature. It is important to recognise that this attribute suffers from the same Populated with point data of species records (based on presence only, not abundance). This attribute requires identification of aquatic
species in the assessment unit—scored* as follows: – endemic to the assessment unit = 3 – endemic to the Surface Water Management Area = 2 – endemic to the LEB drainage division = 1. *Species is only scored once per assessment unit at the highest relevant level. surrogate for broader species conservation in the absence of complete species richness data (Bonn, Rodrigues & Gaston 2002; Lamoreux et al. 2006). (presence/absence only)—required identification of endemic species at the drainage division and catchment scales (primarily made by expert opinion), and species records. Criterion 5: Naturalness: The ecological character of the aquatic ecosystem is not adversely affected by modern human activity. River Disturbance Index Metrics: • Mean Catchment Disturbance Index • Mean Flow Regime Disturbance Index. The River Disturbance Index (RDI) uses data on human disturbances at the catchment and stream scale to rate streams in terms of naturalness (Stein, Stein & Nix 1998). The RDI consists of a number of sub-indices and has been applied across all of Australia. In terms of the LEB HEVAE trial, two sub-indices (each the result of several factors) were selected as indicative of ‘naturalness’ at the assessment unit scale: • Catchment Disturbance Index (CDI) includes consideration of settlements, infrastructure, land use and point sources of pollution • Flow Regime Disturbance Index (FRDI) includes consideration of impoundments, flow diversions and levee banks. Although weeds and pest animals are considered significant threats to aquatic ecosystems in the LEB, there was inconsistent data across the drainage division to include a measure of these disturbances at this time. Similarly, land use and land tenure data was not in the appropriate format across all jurisdictions for use as a surrogate for disturbance. Data is available as an ArcGIS database from Geoscience Australia that contains the CDI and FRDI for all river segments in the Australian 1:250 000 topographic layer. The CDI and FRDI for each assessment unit were calculated as the mean value for all river segments within each unit.