Wallpolla Island
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Flora and Fauna Assessment - Wallpolla Floodplain Restoration Project 5 Overview of existing conditions – Wallpolla Island Wallpolla Island consists of a variety of habitats including River Red-gum (Eucalyptus camaldulensis), Black Box (Eucalyptus largiflorens), lignum shrub land and saltbush. Wallpolla Island is an environmentally significant area that is critically important to the biodiversity of the entire Lower Murray region. Wallpolla Island is a wetland of national significance and is listed in the Directory of Important Wetlands in Australia (Environment Australia 2001). According to a PMST Search, three Ramsar Wetlands are downstream of Wallpolla Island; Banrock Station Wetland Complex (240 km downstream of Wallpolla), Riverland (100 km downstream of Wallpolla) and The Coorong and Lakes Alexandrina and Albert Wetland (555 km downstream of Wallpolla). The watercourses located within the floodplain are lined by dense riparian vegetation that provides habitat for small fish and turtles. Low-lying meander loops near the river channel are frequently flooded by relatively small peaks in river flow and support river red gum woodland and forest. Wetlands within these areas, including the Lilyponds and Horseshoe Lagoon provide semi-permanent wetland habitat and can support breeding by significant numbers of waterbirds. Woodlands higher on the floodplain are dominated by Black Box woodland and provide a productive habitat for woodland birds, mammals and reptiles (Ecological, 2014). Lignum shrubland is present across extensive areas of Wallpolla Island. Flooded lignum shrublands provide nesting platforms for waterbirds. Flooded lignum is a highly productive aquatic habitat, providing abundant food and physical habitat for small native fish species and frogs. Permanent waterbodies provide an aquatic refuge from which frogs, such as Growling Grass Frog (Litoria raniformis) and can disperse to temporary floodplain habitat during floods. Cryptic waterbirds, including the Baillon's Crake (Porzana pusilla) live in dense reedy vegetation. Fish-eating waterbirds, such as the White- bellied Sea-Eagle (Haliaeetus leucogaster) perch in trees near watercourses and hunt in the channels. Wallpolla Island has a diverse array terrestrial fauna populations of birds, reptiles and mammals. Woodlands, shrublands and floodplains within Wallpolla Island supports a range of species including Western Grey Kangaroo (Macropus fuliginosus) and Red Kangaroo (Osphranter rufus) that feed in grasslands and woodlands and benefit from the forage provided by wetland vegetation (Ecological, 2014). Habitat within Wallpolla Island also provide productive habitat resources for species such as De Vis’ Banded Snake (Denisonia devisi), Inland Carpet Python (Morelia spilota metcalfei), insectivorous bats and woodland birds. Lignum shrublands provide cover and a source of prey for small mammals and are the preferred habitat of Giles’ Planigale (Planigale gilesi) (Ecological, 2014). The area represents an important biodiversity corridor that enables the movement and migration of fauna species, and provides resilience to climate change. Many mammals, birds, reptiles and amphibians including Chocolate Wattled Bat (Chalinolobus morio), Short-beaked Echidna (Tachyglossus aculeatus), Lace Monitor (Varanus varius), Inland Carpet Python, Growling Grass Frog and woodland birds, live in both the floodplain and terrestrial landscapes (Ecological, 2014). Further detail on the flora and fauna present within the Wallpolla Island floodplain complex during this current survey is provided in Section 6 and 7. S297772-AP-EN-RP-001 52 Flora and Fauna Assessment - Wallpolla Floodplain Restoration Project 6 Threatened species assessment Targeted surveys for rare or threatened species were undertaken from October 2019 – January 2020 within the proposed Construction Footprint. These areas contained intact native vegetation and it was considered possible that they support suitable habitat for rare or threatened species. 6.1 Threatened Flora Assessment 6.1.1 Desktop Assessment and Likelihood of Occurrence VBA and PMST searches identified 83 threatened flora species, including seven EPBC listed flora species, and/or 14 FFG listed threatened flora species and/or 81 DELWP Advisory listed threatened flora species that have been recorded or have the potential to occur within the Study Area. Each of these 83 species were then assessed for their likelihood of occurrence within the Area of Investigation and Inundation Area (Appendix B), taking into account factors such as the habitat requirements of each species and comparing those to the habitats encountered within the Wallpolla Construction Footprint, and also the number of recent records within the Study Area. A conservative approach to EPBC listed flora species has been taken for this assessment, and whilst it is considered unlikely that any EPBC listed flora will be impacted by the proposed works, all EPBC listed flora species identified by a PMST have been considered in detail. As such, a significance assessment against the EE and EPBC criteria for potential impacts from the proposed construction and inundation is provided in Appendix F. These 83 species were also assessed for their likelihood of occurrence within the Inundation Area. The modelled mapping within the Inundation Area indicated the potential presence of small patches of Semi-arid Woodland. These areas were ground truthed in June 2020 and found to be dominated by Black Box woodland and lignum communities. The results of this assessment are detailed in Section 7 and summarised in Table 7. Table 3 Summary of likelihood of occurrence assessments for rare or threatened flora Construction Footprint Inundation Area Present 35 Not assessed Possible 13 56 Unlikely 35 27 Total 83 83 EPBC and FFG Act-listed flora Eighteen of the listed species identified in the desktop assessment as potentially occurring within the Study Area are listed under the EPBC Act and/or FFG Act. It is considered unlikely that eight of these species would be present within the Construction Footprint or area of inundation, and the remaining ten species have either been identified during the field assessments of the Construction Footprint, or it is considered possible that they may occur within either the Construction Footprint and/or the area of inundation due to the known or potential presence of suitable habitat. Some species have been identified as ‘possibly occurring’ within the Construction Footprint and/or Inundation Area, but as having a low likelihood of being impacted. This has arisen in situations where even though preferred habitat is present (meaning likelihood of occurrence is possible), an impact on these species has been deemed as unlikely, as the species has not been recorded during targeted surveys at the appropriate time of the year. However, it should be noted that due to the prevailing drought conditions, the response of many ephemeral species has been muted, and absence during the 2016 and 2019 targeted surveys does not necessarily imply that the species is not present – it may still reside in the soil as underground tubers, rootstock or seed, waiting for appropriate moisture to trigger germination. A detailed assessment of all of these species’ likelihood is included in Appendix B. S297772-AP-EN-RP-001 53 Flora and Fauna Assessment - Wallpolla Floodplain Restoration Project 6.1.2 Threatened flora recorded during 2019 surveys No EPBC Act-listed flora were recorded during the surveys, however thirteen species listed as threatened under the DELWP Advisory list , including three species listed under the FFG Act were recorded (Table 4 and Table 7). A summary of the listed threatened and protected flora species recorded during the 2019 targeted surveys is provided in Table 4. The location of significant populations of rare or threatened species identified during surveys at the site are shown in Figure 4. Table 4 Rare, threatened and protected flora identified at the Construction Footprint during October 2019 surveys Key: L (Threatened under the FFG Act), P (Protected under the FFG Act). vu (Vulnerable under VROTS), r (Rare under VROTS) Scientific Common Status Location of recent Photo name name records Acacia Umbrella L, vu 5 individuals/clusters oswaldii Wattle (Page 10, 12 and 13 Figure 4) Atriplex Baldoo r 3 individuals/clusters lindleyi (Page 19 and 22 subsp. Figure 4) conduplicata Atriplex Dwarf Old- r >10 individuals/clusters nummularia man within the investigation subsp. Saltbush area (Figure 4) omissa S297772-AP-EN-RP-001 54 Flora and Fauna Assessment - Wallpolla Floodplain Restoration Project Scientific Common Status Location of recent Photo name name records Calotis Blue Burr- P, r >5 individuals/clusters cuneifolia daisy (Page 13 and 23 Figure 4) Crinum Darling Lily L, vu >3 individual/clusters flaccidum (Page 23 Figure 4) Dianella Leek Flax- vu >2 individuals/clusters N/A porracea lily (Page 23 Figure 4) Duma Spiny r >10 individuals/clusters horrida Lignum scattered within the subsp. investigation area horrida (Figure 4) Eragrostis Cane Grass vu >15 individuals/clusters australasica scattered within the investigation area (Figure 4) S297772-AP-EN-RP-001 55 Flora and Fauna Assessment - Wallpolla Floodplain Restoration Project Scientific Common Status Location of recent Photo name name records Eremophila Spreading r NA divaricata Emu-bush subsp. divaricata Eremophila Spotted r >6 individuals/clusters maculata Emu-bush scattered within the subsp. investigation area maculata (Figure 4) Malacocera