Flora and Fauna Report
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Ravenswood/West Murray 2A Infill Sewerage Project Level 1 Flora and Opportunistic Fauna Survey Prepared for Golder Associates June 2012 23 Croyden Road Roleystone WA 6111 Ph: +61 (08) 9397 9853 Fax: +61 (08) 9397 9854 [email protected] Ravenswood/West Murray 2A Infill Sewerage Project Flora and Fauna Ravenswood/West Murray 2A Infill Sewerage Project Level 1 Flora and Opportunistic Fauna Survey Prepared for Golder Associates Document Status Author Reviewer Date of Issue Draft Report CK DK DISCLAIMER This document has been prepared in accordance with and subject to an agreement between Anders Environmental Consulting and Golder Associates and no representation is made to any third party. Any organisation or person that relies on or uses this document for purposes or reasons other than those agreed by Anders Environmental Consulting and Golder Associates, does so entirely at their own risk and Anders Environmental Consulting denies all liability in tort, contract or otherwise for any loss, damage or injury (whether in negligence or otherwise) that may be suffered as a consequence of relying on this document for any purpose other than that agreed with Golder Associates. ii Ravenswood/West Murray 2A Infill Sewerage Project Flora and Fauna EXECUTIVE SUMMARY The Western Australian State Government Infill Sewerage Program is a major capital works program which will enable properties to connect to a centralised wastewater sewerage system. The Water Corporation propose to commence construction of the Ravenswood/West Murray 2A Infill Sewerage Project. The West Murray 2A Infill Sewerage Project comprises construction of the following infrastructure: Approximately 1.3 km of dual DN110PE pressure sewer pipeline Approximately 1.5 km of DN150 gravity sewer pipeline with associated access chambers A pump station with a wet well to be founded at depth of approximately 9 m below ground level Connections to an existing pressure pipeline and gravity sewer system The ground surface elevations along the pipe line alignments and pumping station generally range between RL 3 m AHD and RL 6 m AHD, with the higher elevation at the pumping station site.Golder Associates commissioned Anders Environmental Consulting to undertake a Level 1 flora and opportunistic fauna survey of the Project area. The objectives of the survey were to: • develop an inventory of flora and fauna species present within the Project area; • map vegetation communities and their condition occurring within the Project area; • conduct a targeted search for threatened flora species within the Project area; • conduct an opportunistic fauna survey of habitat trees; and • determine any potential impacts the Project may pose on threatened flora, vegetation and fauna. Flora, vegetation and fauna of the Project area The database searches identified a total of 54 threatened flora species, 17 threatened fauna species and eight threatened ecological communities potentially occurring within Project area. A total of 34 flora species (including subspecies and variants) were recorded during the survey, including eight weed species, one of which (Lantana camara) is a Weed of National Significance. Five vegetation communities were identified during the survey, the planted roadside verge has been included however it should be noted that it is not considered to be a naturally occurring vegetation community. Approximately 0.81 hectares of native vegetation is expected to be cleared with a further 0.57 hectares expected clearing within cleared paddocks and 1.28 hectares expected clearing within urban areas. Two Marri (Corymbia calophylla) habitat trees and a termite mound within vegetation community ErNfW are expected to be directly impacted through clearing. iii Ravenswood/West Murray 2A Infill Sewerage Project Flora and Fauna A large number of habitat trees were recorded within the Project area these include: • 16 locations of Marri (Corymbia calophylla); • 1 location of Blackbutt (Eucalyptus patens); and • Flooded gum (Eucalyptus rudis) throughout the Project area. A total of eight bird species where recorded within the Project area. Threatened flora, fauna and ecological communities Two threatened flora species were recorded within the Project area, Grevillea manglesii subsp. ornithopoda (P2) and Eucalyptus rudis subsp. cratyantha (P4). Both species occur along the riverbank as part of the riparian vegetation. Spotlighting of habitat trees was conducted throughout the Project area, the Common Brushtail Possum (Trichosurus vulpecular), which has a conservation status of least concern under the IUCN Red List was recorded at two locations of Flooded Gum. Black Cockatoo calls were heard briefly at a distance from the Project area, however they were not sighted to enable identification of species. Track activity was recorded along the riverbanks which are potentially either that of the native Water Rat (Hydromys chrysogaster), a Priority 4 listed species under the Wildlife Conservation Act (1950) or the introduced Brown Rat (Rattus norvegicus). A large termite mound was recorded within the planted road verge scrub. Numbats (Myrmecobius fasciatus) feed on termites, however signs of Numbat activity was not present. No threatened ecological communities were present in the Project area. Recommendations The following recommendations are made to reduce the potential impact on threatened flora and fauna and ecological values of the Project area: • Clearing of threatened flora species Grevillea manglesii subsp. ornithopoda and Eucalyptus rudis subsp. cratyantha should be avoided. Areas of native vegetation in particular along river banks which require clearing, should be assessed for the presence of threatened flora prior to clearing; • Clearing of habitat trees should be avoided, including Marri (Corymbia calophylla) and Flooded Gum (Eucalyptus rudis); iv Ravenswood/West Murray 2A Infill Sewerage Project Flora and Fauna • Clearing of vegetation along riverbanks should be minimised to reduce the risk of erosion and disturbance to any potential Water Rat populations; • Targeted survey of Black Cockatoo species is required to determine their presence within the Project area; • Further investigation of Common Brushtail Possum populations present within the Project area should be undertaken; • Minimise usage of heavy equipment along riverbanks to prevent erosion; and • Conduct weed hygene practices on plant and equipment. v Ravenswood/West Murray 2A Infill Sewerage Project Flora and Fauna Table of Contents 1.0 Introduction ........................................................................................................................................ 1 1.1 Project background ....................................................................................................................... 1 1.2 Scope and objectives .................................................................................................................... 1 2.0 Existing environment ......................................................................................................................... 3 2.1 IBRA bioregion .............................................................................................................................. 3 2.2 Climate .......................................................................................................................................... 3 2.3 Land use ........................................................................................................................................ 4 3.0 Method .............................................................................................................................................. 5 3.1 Flora survey design ....................................................................................................................... 5 3.1.1 Desktop study ............................................................................................................................ 5 3.1.2 Vegetation mapping .................................................................................................................. 5 3.1.3 Targeted flora search ................................................................................................................ 6 3.1.4 Specimen identification ............................................................................................................. 6 3.2 Fauna survey design ..................................................................................................................... 7 3.2.1 Fauna habitat identification ....................................................................................................... 7 3.2.2 Fauna observations ................................................................................................................... 7 3.3 Survey timing and personnel ......................................................................................................... 8 3.4 Limitations of the survey ............................................................................................................... 9 4.0 Results ............................................................................................................................................ 10 4.1 Database searches ..................................................................................................................... 10 4.2 Flora survey ................................................................................................................................