Forgotten fish habitats: developing a conceptual framework for evaluating intermittent waterways and flood channels as native fish habitats: insights from two freshwater catchments in Australia

The ability to correctly identify Potential Key Fish Habitats (PKFH) before undertaking development assessments or stream restoration projects is a critical step for determining appropriate management interventions and offset strategies to minimize damage to all life stages of fish. However, there are no rapid, low-cost tools that can be universally utilised to identify PKFH in perennial streams and ephemeral streams in particular. We propose a conceptual framework for developing a rapid field appraisal based on a range of physical fish habitat-supporting features. Four steps are involved in developing the framework: 1) understand fish habitat features using published literature and sub-set model selection using actual data, 2) collect field data, 3) develop the conceptual framework, and 4) classify sites. We tested eight fish habitat-supporting features in the assessment and proposed a decision tree that guided the rapid appraisals at 104 ephemeral sites in southeast Australia. Out of 104 sites, 86% were identified as PKFH, 10% as likely key fish habitats and 4% as unlikely key fish habitats. The rapid field appraisal is cost-effective, simple to implement and does not require expert knowledge of fish habitats. Despite some limitations in the conceptual framework, this appraisal has great potential as a screening technique for PKFH in freshwater streams, particularly ephemeral streams in Australia and other overseas jurisdictions.