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

Where has all the sand gone? Understanding the implications of sand movement following renourishment works to protect Threatened tern habitat in the Gippsland Lakes (#64)

Sean Phillipson 1 , Elisa Zavadil 2 , Olivia Blair-Holt 2
  1. East Gippsland Catchment Management Authority, Bairnsdale, Victoria, Australia
  2. Alluvium Consulting, Melbourne, Victoria, Australia

A collaborative project was completed in 2016 to using dredge spoil to renourish nesting habitat for Threatened terns on sand islands within the Gippsland Lakes. Following this, the distribution of sand has changed, along with patterns of use by terns.

An analysis of the redistribution and loss of sand was needed to understand the ecological impacts of this change, and the implications for future management in a changing climate.

A project to determine the persistence of sand from renourishment works in relation to preferred habitat for small terns, by assessing the loss or gain of sand over time was undertaken.

An analysis of aerial imagery and elevation data was completed, and GIS data tools and algorithms used to consider change in sand distribution over time. Key metrics were then used to assess the distribution and persistence of favourable habitat conditions.

Renourishment works created substantial areas of habitat for tern breeding. The progressive loss of desirable habitat area is limiting the ongoing effectiveness of the renourishment works.

The initial success of the habitat creation indicates that the management approach is effective, with the challenge to then consider how renourishment is prioritised into the future to maximise ecological outcomes.

Increased sea level will impact ecological values in estuarine systems, particularly beach nesting birds. Management interventions can ‘create’ favourable habitat for species.

Understanding the way sand behaves post nourishment, and the required renourishment cycle, is a key tool in helping to maintain vulnerable species and their habitat in a changing landscape.

Download Full Paper