Advice to the Minister for the Environment and Water Resources from the Endangered Species Scientific Subcommittee (ESSS) on a proposal to add an ecological community to Schedule 2 of the Endangered Species Protection Act 1992 (ESP Act)
Name of the ecological community
Corymbia calophylla - Kingia australis woodlands on heavy soils of the Swan Coastal Plain.
Description
This community occurs on the wettest of the soils, and on sites with the highest rainfall, of the group of three Marri (Corymbia— formerly Eucalyptus— calophylla) communities that occur on the heavy soils on the eastern side of the Swan Coastal Plain (Gibson et al. 1994). The community has been assessed by the WA Threatened Ecological Communities Advisory Committee as Critically Endangered.
Listed species in the ecological community
None.
Other native species that could become endangered in the proposed ecological community
None known.
Description of the community 'Corymbia calophylla - Kingia australis woodlands on heavy soils of the Swan Coastal Plain' sufficient to distinguish it from any other ecological community
This community occurs on a variety of land units and soil types. However, the soils in each occurrence all contain an impervious clay layer that would act as a barrier to drainage of water through the soil. As a result, most occurrences become inundated in the wetter months due to rainfall and surface flows. In some areas groundwater is very close to the surface.
A number of plant taxa that occur in the community are typically associated with these seasonally inundated, impervious clay soils. These include Kingia australis, Mesomelaena tetragona, Pericalymma ellipticum, and Hakea ceratophylla.
Typical and dominant native plant taxa in the community are listed in Table 1 below. Community numbers are from Gibson et al. (1994). Although there are some overlaps of typical species with the two other Marri communities with which it is most similar, the differences are clear and consistent. These floristic differences, coupled with measurable differences in rainfall and soil moisture and with very significant differences in rarer species, make the three communities readily recognisable.
| Marri/Kingia Community (3a) | Marri/Jarrah Community (3b) | Marri/Xanthorrhoea Community (3c) |
|---|---|---|
| Trees | ||
| Corymbia calophylla | Corymbia calophylla Eucalyptus marginata |
Corymbia calophylla Eucalyptus wandoo (occasional dominant) |
| Shrubs | ||
| Dryandra nivea Eriostemon spicatus Kingia australis Xanthorrhoea preissii |
Bossiaea eriocarpa Dryandra nivea Hibbertia hypericoides Xanthorrhoea preissii |
Acacia pulchella Dryandra nivea Gompholobium marginatum Hypocalymma angustifolia Xanthorrhoea preissii |
| Herbs | ||
| Cyathochaeta avenacea Dampiera linearis Haemodorum laxum Loxocarya fasciculata Mesomelaena tetragona Tetraria octandra |
Burchardia umbellata Caesia micrantha Chamaescilla corymbosa Conostylis juncea Drosera erythrorhiza Drosera stolonifera Lepidosperma angustatum Lomandra hermaphrodita Loxocarya fasciculata Mesomelaena tetragona Sowerbaea laxiflora Tetraria octandra |
Burchardia umbellata Cyathochaeta avenacea Neurachne allopecuroidea |
The mean species richness for the ten plots in community 3a is 59.7 species in 100 square metres (Gibson et al. 1994), which makes it the most diverse of the three Marri dominated communities.
Evidence that the description of the community 'Corymbia calophylla - Kingia australis woodlands on heavy soils of the Swan Coastal Plain' is conventionally accepted
References and data that support the description and classification of this community are found in the minutes of the WA Threatened Ecological Communities Advisory Committee dealing with the assessment of this community, in the draft interim recovery plan for the community and in the following publications.
Department of Environmental Protection (1994). Threatened or Poorly Reserved Plant Communities Requiring Interim Protection for the Swan Coastal Plain. Preliminary Maps. Environmental Protection Authority, Perth.
Department of Environmental Protection (1996). System 6 update program unpublished site and area records and analysis. EPA, Perth, Western Australia.
Gibson, N., Keighery, B., Keighery, G., Burbidge, A and Lyons, M. (1994). A floristic survey of the Southern Swan Coastal Plain. Unpublished report for the Australian Heritage Commission prepared by the Department of Conservation and Land Management and the Conservation Council of Western Australia (Inc.).
Reasons why the community 'Corymbia calophylla - Kingia australis woodlands on heavy soils of the Swan Coastal Plain' is considered to be endangered within the meaning of Section 6 of the Act
This community fits criteria 2 (a), (d) and (e) for the following reasons.
- The Community has been reduced by >90%, probably about 97%.
- The area remaining is estimated at 83ha, made up of ten highly-fragmented remnants of which none are located in reserves that have their primary purpose as conservation (Waroona reserve is for Parkland and Conservation).
- Remaining patches are threatened by clearing, weed invasion and too frequent fire.
Past and current distributions of the community 'Corymbia calophylla - Kingia australis woodlands on heavy soils of the Swan Coastal Plain'
The series of Marri (Corymbia calophylla), dominated plant communities occurring on heavy soils between Waterloo (near Bunbury) and Bullsbrook are considered to have been some of the most extensive on the eastern side of the Swan Coastal Plain. However they have all suffered extensive clearing and are now rare (Keighery and Trudgen 1992; Gibson et al. 1994, Department of Environmental Protection (DEP) 1996). The wettest sites, dominated by Corymbia calophylla and Kingia australis (this community), occur widely from Bullsbrook north of Perth to Waterloo near Bunbury. This community type has probably been reduced by at least the 97% estimated for vegetation of the eastern side of the Swan coastal plain as a whole.
There are only approximately 83 hectares of the community remaining, on ten separate occurrences. Of this, about 51 hectares is on lands vested in Shire Councils, five hectares is vested with state government agencies, 25 hectares is on private land, and about two hectares is in unvested reserves.
References that support information given in the nomination
Churchward, H.M. and McArthur (1980). Landforms and Soils of the Darling System. In: Atlas of Natural Resources, Darling System, Western Australia. Perth, Pinjarra and Collie Sheets. Department of Conservation and Environment, Western Australia.
Davidson, W.A. (1995). Hydrogeology and Groundwater Resources of the Perth Region, Western Australia. Geological Survey of Western Australia. Bulletin 142.
Department of Conservation and Environment (1985). Conservation reserves for Western Australia; as recommended by the Environmental Protection Authority - 1983. The Darling System - System 6. Report 13, DCE, Perth.
Department of Conservation and Land Management (1990). Data on the Conservation of Vegetation Associations on the Swan Coastal Plain. Unpublished Report.
Department of Conservation and Land Management (1997). Declared Rare and Priority List for Western Australia. Department of Conservation and Land Management, Perth.
Department of Environmental Protection (1994). Threatened or Poorly Reserved Plant Communities Requiring Interim Protection for the Swan Coastal Plain. Preliminary Maps. Environmental Protection Authority, Perth.
Department of Environmental Protection (1996). System 6 update program unpublished site and area records and analysis. EPA, Perth, Western Australia.
English, V. and Blyth, J. (1997). Identifying and Conserving Threatened Ecological Communities in the South West Botanical Province. Project N702, Final Report to Environment Australia. Department of Conservation and Land Management. Perth, Western Australia.
Gibson, N., Keighery, B., Keighery, G., Burbidge, A and Lyons, M. (1994). A floristic survey of the Southern Swan Coastal Plain. Unpublished report for the Australian Heritage Commission prepared by the Department of Conservation and Land Management and the Conservation Council of Western Australia (Inc.).
Keighery, B. (1995). Knowing and Managing the Brixton Street Wetlands. Report compiled for the Friends of Brixton Steet Wetlands and the Perth Branch of the Wildflower Society of Western Australia (Inc.), in cooperation with the Department of Conservation and Land Management.
Keighery, B. (1996). Flora Information for Roadside Bush Protection Plans in the Shire of Serpentine - Jarrahdale. Report prepared for the Roadside Care Volunteers. Perth, Western Australia.
Keighery, B.J., Keighery, G.J., and Gibson, N. (1997). Floristics of Reserves and Bushland areas of the Perth Region (System 6) Parts XI - XV. Wildflower Society of Western Australia (Inc.), Nedlands.
Keighery. B. and Trudgen, M (1992). Remnant Vegetation on the Alluvial Soils of the Eastern Side of the Swan Coastal Plain. Unpublished report for Department of Conservation and Land Management, Australian Heritage Commission and Heritage Council of WA.
Keighery, G.J. and Keighery, B.J. (1993a). Floristics of Reserves and Bushland Areas of the Perth Region (System 6). Parts V - IX. Wildflower Society of Western Australia (Inc.), Nedlands.
Keighery, G.J. and Keighery, B.J. (1993b). Floristics of Reserves and Bushland Areas of the Perth Region (System 6). Parts II- IV. Wildflower Society of Western Australia (Inc.), Nedlands.