Pre-Recorded Oral Presentation as part of National Virtual Conference AFSS Conference 2020

Changes in the composition of wetland-associated birds in Lagoon of Islands, Tasmania after dam removal. (#112)

Leon A Barmuta 1 , Zoe Ezzy 1 , Carolyn Maxwell 2 , Eric Woehler 1
  1. University of Tasmania, Hobart, TAS, Australia
  2. Hydro Tasmania, Hobart, TAS, Australia

This project aimed to assess the recovery of wetland-associated avifauna in the Lagoon of Islands, Tasmania, which is only the second wetland in Australia to be returned to seasonal hydrological regimes by removal of a dam in 2013 after it was inundated in 1964. The current wetland-associated avifauna was compared with adjacent permanent wetlands with contrasting water management regimes via visual surveys of aquatic, littoral and near-shore habitats. This study was distinctive in that we tried to quantify the composition of all wetland-associated birds, not just waterfowl.  Historical records were also analysed from all these wetlands to compare the community composition of birds before, during and after the innundation of Lagoon of Islands. Although most species are shared between these wetlands, Lagoon of Islands had some distinctive species which disappeared during innundation but have subsequently returned (e.g. Lewin’s Rail), others that persisted throughout (e.g. Little Grassbird), while Australasian Bittern has not been recorded since the early 2000s. Some deep-water species (e.g. Hardhead) characterised the inundated period and have disappeared after dam removal, but these are well-represented in the adjacent permanent wetlands. Overall, there are encouraging signs that the species composition of birds is recovering to a pre-inundation configuration, and more targetted surveys are needed for cryptic species of special concern (e.g. Australasian Bittern) to determine whether they have gone locally extinct. More surveys of naturally seasonal wetlands in this region are warranted to understand how Lagoon of Islands contributes to the beta-diversity of this region. In addition, the surrounding manipulated wetlands likely provide important refuges for the regional wetland-associated avifauna during droughts.