Biodiversity

Biodiversity

The Swan Region is part of an internationally recognised biodiversity hotspot, due to its high floral diversity and endemism (uniqueness) and the fact that less than 30% remains (Critical Ecosystem Partnership Fund 2014). The south west of Western Australia contains around half of Australia’s known flowering plants, ferns and cycads, with 79% of the plants species unique to the area (Beard et al. 2000). Within the Swan Region, there are over 2,200 species of plants, with diversity concentrated on the Pinjarra Plain, the Foothills of the Darling Escarpment and the Bassendean Dune woodlands. The Region is also known for its diverse herpetofauna, including 16 frogs, 2 freshwater turtles, 51 lizards and 24 snakes (Hopper et al. 1996).

The Swan Region includes the Swan Coastal Plain Interim Biogeographic Regionalisation for Australia (IBRA) region and the Jarrah Forest IBRA region (Figure 8). Extensive clearing across the Swan Coastal Plain IBRA has resulted in this region having one of the highest densities of threatened flora, fauna and ecological communities of anywhere in Western Australia (Environmental Protection Authority 2007). Both the Jarrah Forest and Swan Coastal Plain IBRA regions are considered to be under a high level of biodiversity stress, with clearing, fragmentation, and infestations of Phytopthora dieback and exotic weeds the major threats (Department of Conservation and Land Management 2002).

The Bush Forever program was originally established to meet the World Conservation Union’s standard for protecting 10% of the original vegetation types in the Swan Coastal Plain. It identified 51,200 hectares of regionally significant bushland and their associated wetlands, covering 26 vegetation complexes on the Swan Coastal Plain. This amounted to 18% of the original vegetation on the Swan Coastal Plain in the Perth Metropolitan Area.  This vast area was grouped into 287 Bush Forever sites, ranging in size from 1 hectare to over 9,000 hectares and were comprehensively catalogued, mapped, and their natural values described. Currently, 39,500 hectares (77%) of the listed Bush Forever sites are under nature conservation tenure by the Department of Parks and Wildlife (Figure 9). Some 94 sites have been rezoned to ‘Parks and Recreation’ reservation. However, as of August 2012, 101 sites did not have a management agency assigned to them and some vegetation complexes (e.g. Karrakatta Central and South, Bassendean Central and South) were estimated to have less than 10% secured and protected within the Perth Metropolitan Region (Urban Bushland Council 2013).

This rich array of wildflowers is just a glimpse to the lengthy list of over 2,200 species of plants that occur in the Swan Region.

Map of native vegetation

Beard vegetation associations in the Swan Region and the proportion of vegetation remaining

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Map of the conservation network

The conservation network and Bush Forever sites in the Swan Region

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