Planning for the future Derwent Estuary Saltmarsh Baseline Monitoring and Management July 2020 Inger Visby (Derwent Estuary Program) & Vishnu Prahalad (University of Tasmania) The Derwent Estuary Program (DEP) is a regional partnership between local governments, the Tasmanian State Government, businesses, scientists, and community-based groups to restore and promote our estuary. The DEP was established in 1999 and has been nationally recognised for excellence in coordinating initiatives to reduce water pollution, conserve habitats and species, monitor river health and promote greater use and enjoyment of the foreshore. Our major sponsors include Brighton, Clarence, Derwent Valley, Glenorchy, Hobart and Kingborough councils, the Tasmanian State Government, TasWater, Tasmanian Ports Corporation, Norske Skog Boyer, Nyrstar Hobart Smelter and Hydro Tasmania. Page 2 of 67 Contents 1 Project summary ............................................................................................................................. 5 2 Introduction .................................................................................................................................... 7 2.1 Saltmarshes - importance and threats .................................................................................... 7 2.2 Derwent Estuary Conservation Action Plan ............................................................................ 8 2.3 Vegetation community status and priority actions ................................................................ 8 2.4 Relevant additional resources ................................................................................................ 9 3 Methodology ................................................................................................................................... 9 3.1 Survey overview ...................................................................................................................... 9 3.2 Site selection and locations .................................................................................................. 10 3.3 Historical images ................................................................................................................... 12 3.4 Refugia overlay...................................................................................................................... 13 3.5 Plant surveys ......................................................................................................................... 14 3.6 Bird surveys ........................................................................................................................... 14 3.7 Human impact surveys .......................................................................................................... 14 4 Overall site results ........................................................................................................................ 15 4.1 Plants ..................................................................................................................................... 15 4.1.1 TASVEG communities .................................................................................................... 16 4.1.2 Introduced species ........................................................................................................ 16 4.1.3 Fringing vegetation ....................................................................................................... 17 4.2 Birds ...................................................................................................................................... 18 4.3 Human impacts ..................................................................................................................... 20 4.4 Future extent of saltmarsh ................................................................................................... 21 5 Site survey results, notes and recommendations ......................................................................... 21 5.1 Windermere Bay ................................................................................................................... 22 5.1.1 Further project proposal details ................................................................................... 24 5.1.2 Recommedations .......................................................................................................... 25 5.2 Jordan River .......................................................................................................................... 25 5.2.1 Green Point – additional notes ..................................................................................... 27 5.2.2 Gage Brook – additional notes ...................................................................................... 28 5.2.3 Recommendations ........................................................................................................ 29 5.3 Old Beach .............................................................................................................................. 30 5.3.1 Recommendations ........................................................................................................ 31 5.4 piyura kitina (Risdon Cove) ................................................................................................... 32 5.4.1 Recommendations ........................................................................................................ 34 5.5 Clarence Plains ...................................................................................................................... 34 5.5.1 Recommendations ........................................................................................................ 36 Page 3 of 67 5.6 South Arm (1) ........................................................................................................................ 37 5.6.1 Recommendations ........................................................................................................ 39 5.7 South Arm (2) ........................................................................................................................ 39 5.7.1 Recommendations ........................................................................................................ 41 5.8 South Arm (3) ........................................................................................................................ 41 5.8.1 Recommendations ........................................................................................................ 42 5.9 Lauderdale ............................................................................................................................ 43 5.9.1 Racecourse Flats (RF1, RF2, RF3, RF4) .......................................................................... 45 5.9.2 Recommendations ........................................................................................................ 47 5.9.3 Dorans Road .................................................................................................................. 48 5.9.4 Recommendations ........................................................................................................ 49 5.10 Browns River ......................................................................................................................... 49 5.10.1 Recommendations ........................................................................................................ 52 5.11 Shag Bay (limited survey) ...................................................................................................... 53 5.11.1 Recommendations ........................................................................................................ 53 6 Photo monitored sites .................................................................................................................. 53 6.1 Windermere Bay south ......................................................................................................... 53 6.1.1 Recommendations ........................................................................................................ 55 6.2 Glenorchy Art & Sculpture Park (GASP) ................................................................................ 55 6.2.1 Recommendations ........................................................................................................ 55 6.3 Faggs Gully Creek (Geilston Bay) ........................................................................................... 56 6.3.1 Recommendations ........................................................................................................ 57 6.4 Montrose Bay High School .................................................................................................... 57 6.4.1 Recommendations ........................................................................................................ 59 7 Acknowledgements ....................................................................................................................... 59 8 References .................................................................................................................................... 59 9 Appendix ....................................................................................................................................... 61 9.1 Plant survey results for each site .......................................................................................... 61 9.2 TASVEG community