PROTECTING THE VOLCANIC PLAINS

By on June 12, 2008

The protections applied to the native grasslands of the Victorian volcanic plain may affect members who plan to open sites in the area in the future. SARAH ANDREW reports.

THE native grasslands of the Victorian volcanic plain were recently nominated to be recognised as a Threatened Ecological Communities under the Environment Protection and Biodiversity Conservation Act 1999 (EPBC Act).

After consideration by the ‘Threatened Species Scientific Committee’, the Committee have advised the Minister for the Environment, Heritage and the Arts of their support for this application.

This may affect members who plan to open sites in the future within these areas in that if their application triggers the EPBC Act, there will be a need for additional approvals and detailed studies and management systems. This will result in additional application and management costs for any site able to open in these areas.

DESCRIPTION OF THE AREA

The Natural Temperate Grassland of the Victorian Volcanic Plain is a complex and inherently variable ecological community. The ecological community occurs on a large, Quaternary basaltic plain with scattered volcanic cones and stony rises.

The soils of the plain are heavy grey to red cracking clays, with black cracking clays common in the low-lying areas, and tend to be fertile but with a poor drainage capacity. The climate of the Victorian Volcanic Plain is characterised by hot, dry summers and cold winters with frosts.

The vegetation of the Natural Temperate Grassland of the Victorian Volcanic Plain is mostly limited to a ground layer of grasses and herbs. Large shrubs and trees are absent to sparse.

The ground layer is dominated by native tussock-forming perennial grasses with a variety of herbs, mostly from the daisy (Asteraceae), lily (Anthericaceae, Asphodelaceae, Phormiaceae), pea (Fabaceae) and orchid (Orchidaceae) families, occupying the spaces among grass tussocks.

The main grass species present are Kangaroo-grass (Themeda triandra), particularly on drier sites, Wallaby-grasses (Austrodanthonia spp.), Spear-grasses (Austrostipa spp.) and Tussock-grasses (Poa spp.). Low gradient ephemeral and intermittent drainage lines may be dominated by a dense sward of the River Tussock-grass (Poa labillardierei).

The ecological community supports a diversity of animal species notably skinks, snakes, birds of prey and ground-dwelling birds. Grassland remnants now support very few native mammal species.

The groups which have particularly declined in species richness across the Victorian Volcanic Plain (not necessarily just in grassland) include the rodents, macropods and the bandicoots.

CONDITION THRESHOLDS

The listed Natural Temperate Grassland of the Victorian Volcanic Plain ecological community comprises those patches that meet the key diagnostic characteristics, above, and the condition thresholds, below, for better quality sites of the ecological community.

  1. The total perennial tussock cover represented by the native grass genera Themeda, Austrodanthonia, Austrostipa or Poa is at least 50%; OR
  2. If the total perennial tussock cover represented by the above 4 native grass genera is less than 50%, then the ground cover of native forbs (wildflowers) is at least 50% of total vegetation cover during spring-summer (September to February); OR
  3. The cover of non-grass weeds is less than 30% of total vegetation
    cover at any time of the year

The conservation value of a patch of the Natural Temperate Grassland of the Victorian Volcanic Plain ecological community is enhanced if it shows any of the following features:

  • a high native plant species richness;
  • large patch size;
  • minimal weed invasion;
  • presence of threatened plant and/or animal species;
  • presence of natural exposed rock platforms and outcrops; or
  • presence of mosses, lichens or a soil crust on the soil surface.

FURTHER INFORMATION

Further information on this matter, including a list of the species considered, is available from www.environment.gov.au

The photos included in this article were sourced fr om Victorian Resources
Online http://www.dpi.vic.gov.au/dpi/vro/vrosite.nsf/pages/ecorich_photo_gallery

The endangered Prasophyllum suaveolens Fragrant
Leek Orchid at Darlington on the Volcanic Plains

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