Short Virtual Presentation & Digital Poster 10th Australian Stream Management Conference 2021

The recovery of riparian vegetation along rivers of coastal NSW since the 1980s: Implications for working with river recovery in management (#39)

Nuosha Zhang 1 , Kirstie Fryirs 1 , Timothy Ralph 1 , Tim Cohen 2
  1. Macquarie University, Macquarie Park, NSW, Australia
  2. ARC Centre of Excellence for Australian Biodiversity and Heritage, University of Wollongong, Wollongong, NSW, Australia
  • Clearance of vegetation and de-snagging activities throughout the 19th and 20th centuries caused widespread river channel degradation across eastern Australia. However, following decades of effort in river management, there has been a noticeable shift in the condition of these rivers, particularly in coastal valleys of NSW. While geomorphic and vegetative recovery have been observed, we do not yet fully understand the geomorphic processes and vegetation mechanisms by which this recovery is occurring. This understanding is critical to work with rivers as part of nature-based and process-based management practice.
  • Remote sensing data, topographic data, historical images and field measurements were used to identify and quantify changes in riparian vegetation and channel geomorphology over the last 70 years in coastal rivers of NSW. We constructed recovery trajectories, considering interactions between riparian vegetation and channel geomorphology, to understand the mechanisms driving recovery for different types of rivers.
  • Preliminary results show that riparian vegetation has increased greatly in extent over the period of investigation. Associated with this has been stabilisation of many instream geomorphic units such as river banks, bars and benches.  
  • This research provides an understanding of when and how river recovery is occurring and the trajectories of channel adjustment. This understanding will help to make forecasts about the future geomorphic and vegetative condition of rivers in coastal NSW.  In collaboration with our industry partners, we hope to identify where there are opportunities to work with river recovery in practice, and to help prioritise investments in river rehabilitation into the future. 
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