B1. Relationships to other listed Matters of National Environmental Significance
B1.1. RAMSAR wetlands
As of September 2014, only one wetland of international importance (RAMSAR wetlands) occurs within the wheatbelt region: Toolibin Lake. This is an extensive seasonal wetland system, located about 50 km east of Narrogin, and characterised by a woodland of Casuarina obesa and Melaleuca strobophylla across the bed of the lake. It is the only freshwater wetland in south-western Western Australia that retains living and functional woodlands of this type. The site is also recognised as a nationally endangered ecological community under the name: Perched wetlands of the Wheatbelt region with extensive stands of living sheoak and paperbark across the lake floor (Toolibin Lake). An equivalent ecological community is listed as critically endangered in Western Australia.
The vegetation across the bed and edges of Toolibin Lake is not part of the WA Wheatbelt Woodlands ecological community, as it is a type of non-eucalypt woodland. However, the higher ground around the lake includes some patches of open eucalypt woodland (McMahon, 2006). The eastern and northern sides are dominated by woodlands of Eucalyptus loxophleba - Acacia acuminata, along with Allocasuarina and Banksia woodlands with some heathland. Eucalyptus salmonophloia, E. wandoo and E. longicornis also may be present at the site. An overstorey of E. rudis may formerly have occurred on the lake bed but this tree is now rare across Toolibin Lake.
B1.2. World Heritage properties and National Heritage places
As of June 2015, no world heritage properties are located within the WA wheatbelt.
The National Heritage List includes one item within the wheatbelt. The Goldfields Water Supply Scheme is a pipeline and associated infrastructure that was constructed between the late 1890s and 1903 to supply water to the goldfields region (DoE, 2014b). The pipeline stretches for 560 km between Mundaring Weir, near Perth, and Mount Charlotte Reservoir, near Kalgoorlie, so traverses the wheatbelt and extends into the Great Western Woodlands. The National Heritage listing is limited to the built structures associated with the water supply scheme and does not include any natural features, such as woodland or other native vegetation remnants, through which the pipeline may run. It is therefore separate to the WA Wheatbelt Woodlands, even if some remnants may occur in proximity to the pipeline.
B1.3. Other nationally-listed threatened ecological communities
As of June 2015, two nationally listed ecological communities extend into the wheatbelt region. One of these is Toolibin Lake, described above under Ramsar wetlands.
The other is the critically endangered Claypans of the Swan Coastal Plain ecological community. Most claypans lie in the Swan Coastal Plain bioregion, but a few outlying sites occur in the vicinity of Kojonup, in the Southern Jarrah Forests region. This is a largely cleared area that falls within the definition of wheatbelt for this conservation advice. The claypans are generally shrublands or herbfields associated with poorly draining clay soils that are seasonally inundated after rain, then dry out. Eucalypts are noted as emergents at some claypan sites, but are likely to be too sparse to form a woodland canopy. Hence, there is no significant overlap between the WA Wheatbelt Woodlands and the Claypans of the Swan Coastal Plains ecological communities.
The national claypans ecological community covers three of the six clay-based wetland communities identified by Gibson et al. (2005). Of the other three excluded claypan communities, one (claypan community 4) occurs on floodplain below a woodland canopy of E. wandoo and E. occidentalis, also in the Kojonup area. Given its location and canopy composition, this claypan community is likely to fall within the definition of the WA Wheatbelt Woodlands. Another excluded community (claypan community 6) also occurs in the wheatbelt and generally are woodlands dominated by Casuarina obesa, Melaleuca strobophylla or E. loxophleba. Those elements of community 6 that lie below a York gum-dominated woodland canopy also would be captured in the WA Wheatbelt Woodland ecological community.
While there are several nationally-listed ecological communities in WA that are, or include components of woodlands, these occur in bioregions outside of the wheatbelt and are characterised by tree species and growth forms that are not typical of the WA Wheatbelt Woodland ecological community. Examples include: ‘Corymbia calophylla - Kingia australis woodlands on heavy soils of the Swan Coastal Plain’, which lies within the Swan Coastal Plain bioregion and is dominated by marri; and the ‘Proteaceae Dominated Kwongkan Shrublands of the Southeast Coastal Floristic Province of Western Australia’ that generally lies in the Esperance Plains bioregion, south of the wheatbelt and comprises shrublands dominated by proteaceous species (chiefly Banksia), sometimes with a mallee overstorey. Along with their different bioregional distributions, the dominant presence of marri, Banksia or mallee eucalypt species indicates that the WA Wheatbelt woodlands are not present.
B1.4. Nationally threatened species
Southwestern WA, including the wheatbelt, is a biodiversity hotspot. The region has a very high diversity of native species, many of which occur nowhere else; for instance, of the more than 5700 native plant species in this area, over 70% are endemic to the region. Many species in the wheatbelt are now considered to be threatened as a consequence of widespread clearing and loss of habitats in the past. There are 16 animal taxa and 71 plant taxa that are either known to, or potentially could occur in the WA Wheatbelt Woodland ecological community, and are listed as nationally threatened taxa (Table B1). These include iconic Western Australian animals such as the woylie, numbat, and chuditch, and numerous wildflower species.
Many of the nationally-listed species, along with other species, also are recognised as threatened under Western Australian legislation. Regional guides to the state-listed plant species have been prepared by Graham and Mitchell (2000) for the Katanning district, Durrell and Buehring (2001) for the Narrogin district, Stack et al., (2006) for Wongan-Ballidu Shire, and Collins (2009) for the western central wheatbelt.
Table B1. Nationally listed threatened species that are either known to be present, or are likely to be present to some extent, within the WA Wheatbelt Woodlands ecological community. Current as at April 2015.
Sources: DoE (2014c). Protected Matters Search Tool undertaken for the wheatbelt region, as defined in this conservation advice. Scientific and common names, national distributions and available habitat information were checked using the Atlas of Living Australia, WA Herbarium Florabase, DoE (2014d) and Collins (2009).