Werribee Plains Biodiversity Connectivity Report - Australian ...

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important to emphasise that high quality grassland habitats (in terms of structure and composition) are essential for maintaining many threatened species populations and for maintaining ecosystem function. Efforts to reconnect grasslands without simultaneously protecting and enhancing existing habitats will be meaningless and will result in poor biodiversity outcomes. Examples of threatened species requiring high quality grassland habitats include: Plains Wanderer, Striped Legless Lizard, Red Chested Button Quail, Grassland Earless Dragon, Small Golden Moths and White Diuris. A focus on the protection, enhancement and reinstatement of high quality, appropriately structured grasslands will be essential to sustain and increase populations for these and many other species. The vision for grasslands is thus to reconnect all the existing core grassland remnants (>50ha) and actively manage the network of habitats as an integrated whole. 2.3.3 Coast Coastal areas are often highly diverse environmentally valuable areas, they are also highly vulnerable to climate change and one of the primary growth zones across Victoria. Unlike many other sections of coast in Victorian the Werribee Plains coastal region has been relatively undeveloped due to the presence of the Werribee Treatment Plant and other restrictive land uses such as the Point Cook Air Force Base. The Werribee Western Treatment Complex, Murticum Wildlife Area and Cheetham Saltworks in the Point Cook area also represent some of the most important overwintering sites in Victoria for the nationally Endangered Orange-bellied Parrot (based on DSE Action Statement 43 1993 and GIS data). This Action Statement for this species recommends increasing the amount of saltmarsh habitat and reducing saltmarsh degradation through rabbit and stock grazing as important actions for increasing seed availability to the parrots over the winter period. Such actions could help increase the viability of this species and would also benefit a wide range of other terrestrial and marine species depending on the saltmarsh community. The mapping for coastline prioritises areas for protection, enhancement and restoration based on the current and pre-European distribution of saltmarsh and mangrove shrubland ecological vegetation classes (EVC’s) and the distribution of threatened wetland flora and fauna “hotspots” (high record density areas). Areas that are important for both Orange-bellied Parrot conservation and other threatened wetland flora and fauna are highlighted as being very high priority areas for action. The primary Vision goal for the Werribee Plains coastal area is to maintain the ecological character of Victoria’s Ramsar sites through appropriate conservation and use as identified in the Parks Victoria Strategic Management Plan for the Port Philip Bay Western Shoreline (DSE 2003). Biodiversity connectivity through the region is important from the perspective of increasing habitat for migratory bird species, building ecosystem resilience and maintaining ecosystem services. For example, coastal saltmarsh and mangrove shrublands play an important role in stabilising the coastline, recycling nutrients and locking up pollutants. They also help sustain fish breeding areas and provide important habitats for many marine invertebrates. Many waterbirds feed on the shellfish, plantlife and other invertebrates that form part of this ecosystem, including many threatened species such as: Australasian Bittern, Australian Painted Snipe and Baillon''s Crake. These communities once formed a virtually continuous community along the coastline in the project area, but are now restricted to isolated remnants. 2.3.4 Roadsides and Railways There are high vegetation values within many of the regions roadsides, railways and other linear infrastructure corridors including sites with threatened species. The roadside and railway line vegetation is often fragmented remnants surrounded by farming properties. These linear infrastructure vegetation patches are at risk from greater fragmentation, changes in management regimes and future road and rail developments (such as road widening and construction). The vision for theses areas is to have many of this patches mapped and recorded and where possible incorporated into the broader scale connectivity landscape linking the larger core areas. 2.3.5 Wetlands A variety of freshwater and brackish wetland habitats occur throughout the project area and are an important feature of the region. Major wetland communities include: Plains Grassy Wetland, Plains Sedgy Wetland, Lignum Wetland and Aquatic Herbfield. Threatened species records are associated with many of the wetlands and several wetlands have been mapped as Biosites. The Werribee Water 12
Treatment complex and Murticaim Wildlife Area are important (though modified) freshwater wetland habitats that help sustain threatened bird populations and some frog species including the Endangered Growling Grass Frog. Many of the threatened bird species depend on coastal saltmarsh and associated wetlands as well as freshwater wetlands further inland. Threatened bird species, particularly migratory species, utilise these areas and protection of this habitat is essential. Threats to the Wetlands include changing water regimes, climate change impacts, population growth and nutrient level increase. The Vision for wetlands is to buffer these sensitive areas so that they continue to have the water resources to provide adequate habitat. 2.4 Utilising GIS to assist in setting goals and targets This project is about beginning the process to ensure that the Werribee Plains region continues to have biodiversity connectivity and biodiversity assets into the future. The process of setting goals and targets has begun with the identification of current and proposed regional projects but will require further refinement as the project progresses. 2.4.1 Criteria for connectivity The criteria for mapping landscape linkages and buffer areas within this project are based on achieving the following broad goals: • Maintenance of viable habitats that protect and enhance important biodiversity assets at the ecosystem, vegetation community and threatened species levels; • Maintenance of key ecological processes, such as species dispersal, plant pollination, coastal nutrient recycling, long distance biological movement etc. • Resilience to climate change, in terms of acting to abate existing threats that are likely to be exacerbated by climate change (eg. habitat isolation, weed invasion, coastal erosion)Resilience to disturbance at the local and regional levels resulting from fire regimes, adjacent land use practices and encroaching development; 2.4.2 Mapping and analysis The use of GIS technology has been integral to the development of this project. The setting of connectivity corridors has been developed using a wide range of state held data sets that have the appropriate environmental, infrastructure and resource based data. The major vegetation types (assets) and threatened species (“nested” assets) were determined based on the Werribee Landscape Zone Planning developed by the Department of Sustainability and Environment and from examination of attribute data from the GIS database. This information was used to develop a simple conceptual model incorporating protection, enhancement and restoration objectives within the broader connectivity theme. In line with current scientific literature and NRM policy, key ecological processes underpinning these ecosystems were also identified and incorporated into the conceptual model. To assist in the analysis of the data a separate mapping exercise was performed for different broad ecosystem types: wetlands, coastal saltmarsh, grasslands and riverine corridors/woodlands. The key was to identify the existing habitats for protection and enhancement and from there identify potential key connectivity areas. Individual properties (containing one or more contiguous land parcels) were used as the unit of prioritization for grassland and grassy woodland EVCs (i.e. vegetation within particular land parcels was assigned a priority ranking depending on the criteria outlined below). The advantage of using individual properties, as defined as contiguous land parcels in single ownership, is that we can then automatically have information about the nature of private tenure and planning zoning and overlays. In addition, grassland areas within a particular property are likely to be under a similar management regime, hence “patches” within properties may be of similar quality. The final maps have also included existing and proposed conservation reserves, existing enhancement project areas and a draft conceptual connectivity layer for the Werribee Plains Project Area. 13
Page 1 and 2: WERRIBEE PLAINS Biodiversity Connec
Page 3 and 4: Document Control Version # Descript
Page 5 and 6: • Identify intermediate and long
Page 7 and 8: the world’s environmental “Hot
Page 9 and 10: Figure 1 - Werribee Plains Biodiver
Page 11: 2.3 Vision (50 years) The proposed
Page 15 and 16: Figure 2 - Bioregional distribution
Page 17 and 18: Figure 4 - Werribee Plains Grasslan
Page 19 and 20: Figure 6 - Werribee Plains Regional
Page 21 and 22: connections which can be achieved b
Page 23 and 24: • Address adverse processes and a
Page 25 and 26: 3 Projects Stakeholder liaison has
Page 27 and 28: Projects Partner Groups Project Des
Page 33 and 34: • Increase habitat for migratory
Page 35 and 36: 4.2 Project Outputs As identified i
Page 37: Formal protection of Grassland and

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