Condition thresholds in Australia's threatened ecological community listings hinder conservation of dynamic ecosystems

Abstract

Environmental degradation is threatening biodiversity and ecosystem function globally. Mandating ecosystem-level protection in policy and legislative frameworks is essential to prevent biodiversity loss. Australia’s Environment Protection and Biodiversity Conservation Act 1999 is the key legislative mechanism for supporting biodiversity at the national level, but has so far been ineffective at protecting habitat and ecological communities. Here we identify a major flaw in the current approach to listing threatened ecological communities (TECs): restrictive condition thresholds that threaten ecosystem function in dynamic ecosystems. Using two wetland TECs as a case study (Upland Wetlands and Coolibah-Black Box Woodlands), we argue that Australia’s environmental legislation should adopt a landscape-scale approach to TEC protection that acknowledges ecosystem function, accounts for different states in temporally dynamic systems, and sustains landscape connectivity of TEC distribution. We present a state-and-transition model for each TEC to show how human activities affect the reference-state continuum of wet and dry phases. We also show that the current listed condition thresholds do not acknowledge alternative ecosystem states and exclude areas that may be important for restoration and conservation of the TEC at the landscape-scale. Description of alternative and transitional states for dynamic systems, including how, when and why ecological communities shift between different states, should be formally integrated into the TEC listing process to protect Australia’s vulnerable ecosystems from further degradation and loss.