Additional vegetation assessment within the Werribee Employment Precinct, Werribee, Victoria

Transcription

1 Additional vegetation assessment within the Werribee Employment Precinct, Werribee, Victoria Authors: Ross Dennis (Botanist) and Aaron Organ (Director / Principal Ecologist) Date: 10 th December 2010 Our Ref. Project #: 2635 Introduction Ecology Partners Pty Ltd (Ecology Partners) was engaged by the Growth Areas Authority (GAA) and the Department of Planning and Community Development (DPCD) to undertake additional vegetation assessments within the Werribee Employment Precinct (Figure 1). A habitat hectare assessment of native vegetation that qualifies under Victoria s Native Vegetation Management A Framework for Action (The Framework) (NRE 2002), along with an assessment of whether areas of native grassland constitute the Environment Protection and Biodiversity Conservation Act 1999 (EPBC Act) listed ecological community across the precinct was also mapped. The current report is in addition to a previous preliminary flora and fauna assessment (Ecology Partners 2009), and targeted surveys for significant flora and fauna species (Ecology Partners 2010). Objectives Based on discussions with the GAA, DPCD and the Department of Sustainability and Environment (DSE) the objectives of the assessment were to: Conduct a site survey by a qualified botanist to locate previously identified patches of vegetation (Ecology Partners 2009) referred to as Degraded Treeless Vegetation (DTV), Plains Grassland and Plains Grassy Wetland, and to undertake a habitat hectare assessment of native vegetation that qualifies as a patch under the Framework; Identify any areas of vegetation that qualify as the EPBC Act-listed ecological community; Natural Temperate Grassland of the Victorian Volcanic Plain (NTGVVP); and, Prepare a letter report detailing the findings of the assessment. 1/8

2 Methods Prior to the site assessment a review of the previous vegetation assessment (Ecology Partners 2010) within the study area was undertaken. Habitat scores were calculated based on the published DSE methodology (Parkes et al. 2003; DSE 2004). A vegetation assessment that documented the ecological values within the precinct was undertaken on 29 December The EPBC Act-listed NTGVVP was identified according to descriptions set out in the policy statement released by the Commonwealth Department of Sustainability, Environment, Water, Population and Communities (SEWPaC) (DEWHA 2008). Results Vegetation Communities The extent of vegetation identified during the current assessment is broadly consistent with the previous assessment undertaken within the precinct (Ecology Partners 2009). However, the above average rainfall that occurred this season is likely to have provided more favourable conditions for plant growth, and as such, small additional areas of native grasses were recorded within the study area. Natural Temperate Grassland of the Victorian Volcanic Plain Within areas previously mapped as Degraded Treeless Vegetation (DTV) (Ecology Partners 2009) smaller patches of vegetation are dominated (combined cover between 30-70%) by Kneed Spear-grass Austrostipa bigeniculata Common Wallaby-grass Austrodanthonia caespitosa and Bristly Wallaby-grass Austrodanthonia setacea (Figure 2). Given that native grasses account for greater than 50% of the total perennial tussock cover these patches qualify as NTGVVP. These patches do not qualify as Plains Grassland (EVC 132_61) and therefore do not require a habitat hectare assessment (DSE 2010). In some areas there are patches of previously mapped DTV which are dominated (30-50% cover) by the native Windmill Grass Chloris truncata, often with few, if any other native species present. While these areas are considered MTV (DSE 2010) as there is greater than 25% cover of native species in a treeless understory, they do not meet the condition thresholds (i.e. namely the 50% perennial tussock cover) to constitute NTGVVP. Areas of MTV require a habitat hectare assessment if they are known to, or are likely to provide suitable habitat for a threatened species, or if DSE do not agree that the area is MTV. 2/8

3 Plains Grassy Wetland The extent of Plains Grassy Wetland [Ecological Vegetation Class (EVC) 125] within the precinct is similar to that mapped during the previous assessment (Ecology Partners 2009) (Figure 2). These areas are dominated (60-70% combined cover) by several native species, including Common Spike-sedge Eleocharis acuta, Small Loosestrife Lythrum hyssopifolia, Common Swamp Wallaby-grass Amphibromus nervosus and Short-bristle Wallaby-grass Austrodanthonia setacea. Exotic species identified within these patches include Buck's-horn Plantain Plantago coronopus, Drain Flat-sedge Cyperus eragrostis and Water Couch Paspalum distichum, and these species comprise approximately 20% cover. Given that these patches qualify as Plains Grassy Wetland a habitat hectare assessment was undertaken. Modified Treeless Vegetation (MTV) The majority of areas previously mapped as DTV have further deteriorated and are currently dominated (estimated cover of between 50-90% across different patches) by exotic grasses such as Toowoomba Canary-grass Phalaris aquatica, Perennial Rye-grass Lolium perenne and Chilean Needle-grass Nassella neesiana. These areas constitute MTV (DSE 2010) as they contain less than 25% native understory cover with no canopy trees. Accordingly, areas of MTV are not defined as remnant patches under the Framework, and therefore no formal offsets are likely to be required for their proposed removal. Habitat hectare assessment The site assessment confirmed areas of poor quality Plains Grassland and Plains Grassy Wetland (Ecology Partners 2009). Both EVCs are endangered within Victoria, and based on the habitat score habitat hectare score for Plains Grassy Wetland this vegetation has a conservation significance of high within the precinct (Table 1). 3/8

4 Table 1. Quantity and significance of native vegetation (habitat hectare polygons) within the study area. Habitat Zone HZ1 HZ2 EVC name (initials) PG PGW EVC Number 132_ Max Score Score Score Large Old Trees 10 N/A N/A Canopy Cover 5 N/A N/A Site Condition Understorey Lack of Weeds Recruitment Organic Matter Logs 5 N/A N/A Standardiser Standardised site condition score Landscape Value Patch Size Neighbourhood Distance to Core Habitat points out of Habitat Score (habitat points/100) Area of habitat zone to be removed (ha) Amount of habitat hectares to be removed* Bioregion VVP VVP EVC Conservation Status E E Conservation status x Habitat Score High High Conservation Significance Threatened Species Low Low Other Site Attributes Low Low Overall Conservation Significance (highest rating) High High Notes: PG = Plains Grassland, PG (mod TV) = Modified Treeless Vegetation, PGW = Plains Grassy Wetland, E = Endangered Remnant native vegetation within the study area comprises: 1.38 habitat hectares (6.27 hectares) of High conservation significance Plains Grassland; and, 0.57 habitat hectares (1.89 hectares) of High conservation significance Plains Grassy Wetland. 4/8

5 Net Gain targets If all areas of remnant native vegetation is proposed to be removed within the study area there would be a requirement to generate: 2.07 habitat hectares for the loss of 1.38 habitat hectares (6.27 hectares) of High conservation significance Plains Grassland; and, 0.86 habitat hectares for the loss of 0.57 habitat hectares (1.89 hectares) of High conservation significance Plains Grassy Wetland. However, based on recent discussions it is likely that the Plains Grassy Wetland remnant will be retained in a Melbourne Water storage/treatment area. Table 2. Net Gain habitat hectare targets if Plains Grassland was proposed to be removed. Target # Habitat Zones Bioregion EVC #: Name Conservation significance Min. habitat score for target H2 H1&H3 VVP PG132_61 High 17 H2 HZ2 VVP PGW125 High 23 Other Like-for- Like reqts Similar ecological function OR land protection as impacted by loss Similar ecological function OR land protection as impacted by loss Total Losses (Hha) Habitat Hectares Target Net Outcome Gain Target (Hha) Notes: PG = Plains Grassland, PGW = Plains Grassy Wetland, E = Endangered This precinct forms one of the 28 precincts outlined in the Strategic Impact Assessment Report (SIAR) and any proposed removal of Native Temperate Grassland of the Victorian Volcanic Plain will need to be offset within the proposed 15,000 hectare Western Grassland Reserves, which is consistent with the NTGVVP prescription.. Any approved removal of NTGVVP within the precinct would require an offset under the SIAR at a current cost of $137, per habitat hectare. A Native Vegetation Precinct Plan is also likely to be required for any removal of vegetation within the precinct. 5/8

6 SAYERS ROAD PRINCES FREEWAY POINT COOK ROAD DUNNINGS ROAD EP Map # : 1424 File Path: 1424_Fig01_StudyArea_09Apr10.mxd Issue Date: 12/04/2010 FORSYTH R OAD FORSYTH ROAD BOARDWALK BOU LEVARD PRINCES OUT-PRINCES RAMP OLD GEELONG ROAD SNEYDES ROAD AVIATION ROAD HOGANS ROAD DIGGERS ROAD MORRIS ROAD PRINCES HIGHWAY HOPPERS LANE DUNCANS ROAD DERRIMUT ROAD RAILWAY AVENUE TARNEIT ROAD HEATHS ROAD SYNNOT STREET PRINCES FREEWAY BALLAN ROAD WERRIBEE RACECOURSE WERRIBEE HOPPERS CROSSING AIRCRAFT Legend Werribee Study Area Figure 1 Study Area Werribee Employment Precinct ¹ ,460 Meters BULBAN ROAD PRINCES HIGHWAY

7 Study Area Natural Temperate Grassland of the Victorian Volcanic Plain Hoppers Crossing Station Princes - Princes In Ramp Princes Fwy Federation Trl Plains Grassy Wetland Modified Treeless Vegetation Federation Trl 0.03ha Hoppers Lane 0.08ha 0.03ha Princes Fwy 1.03ha 2.04ha 0.19ha 3.75ha 0.23ha 1.67ha 0.09ha 0.22ha Sneydes Rd 0.42ha 0.24ha Sneydes Rd Princes Fwy FederationTrl FederationTrl PrincesFwy PrincesFwy Princes Fwy Hoppers Lane 1.21ha 0.42ha 0.05ha 0.21ha Figure 2 Ecological features within the Study Area Werribee Employment Precinct Metres Hacketts Rd 2635_Fig02_EcoFeatures_07Jan11.mxd 07/01/2011 ALF

8 References DSEWPC website (undated). DSE website (undated). DSE Vegetation quality assessment manual: Guidelines for applying the habitat hectares scoring method. Biodiversity and Natural Resources Division, Department of Sustainability & Environment, Victoria. DSE Native Vegetation Update: Updated native vegetation management guidelines to the Victoria s Native Vegetation Management A Framework for Action (DNRE 2002). Department of Sustainability & Environment, Victoria. Ecology Partners Pty Ltd Preliminary Flora and Fauna Assessment, Werribee Employment Precinct, Werribee, Victoria. Unpublished report prepared by Ecology Partners Pty Ltd for VicUrban. Ecology Partners Pty Ltd Werribee Employment Precinct: Targeted Flora and Fauna Surveys, Werribee, Victoria. Unpublished report by Ecology Partners Pty Ltd prepared for VicUrban. NRE Victoria s Native Vegetation Management; A Framework for Action. Department of Natural Resources and Environment, East Melbourne, Victoria. Parkes, D., Newell, G. & Cheal, D Assessing the quality of native vegetation: The habitat hectares approach. Ecological Management & Restoration Volume 4 Supplement PPWCMA Port Phillip and Westernport Native Vegetation Plan. Port Phillip and Westernport Catchment Management Authority. 8/8