Weeping Myall - Coobah - Scrub Wilga Shrubland of the Hunter Valley

Advice to the Minister for the Environment and Heritage from the Threatened Species Scientific Committee (TSSC) on amendments to the List of Ecological Communities under the Environment Protection and Biodiversity Conservation Act 1999 (EPBC Act)
01 August 2005

1. Name

This ecological community was nominated under the name Weeping Myall - Coobah - Scrub Wilga Shrubland of the Hunter Valley. This name was considered appropriate for use as the name of the national ecological community.

2. Description

This ecological community consists of a woodland of Weeping Myall (Acacia pendula) up to 10 m high with Coobah (Acacia salicina) and Scrub Wilga (Geijera salicifolia). Yarran (Acacia omalophylla) and Stiff Canthium (Canthium buxifolium) are also present in the small tree/shrub layer. The ground stratum is dense and primarily grassy. Grasses include Kangaroo Grass (Themeda triandra/australis), Wallaby Grass (Austrodanthonia spp.), Snow Grass (Poa sieberiana) and Barbed Wire Grass (Cymbopogon refractus) (Benson in prep.). Some exotic grasses have also invaded the site.

The ecological community occurs in a small stand on heavy, brown clay soil at Jerry's Plains in the Hunter Valley, in the South Hunter Province of the Sydney Basin Bioregion (Benson in prep.).

3. National Context

There is one patch of two hectares of the Weeping Myall - Coobah - Scrub Wilga Shrubland of the Hunter Valley ecological community remaining. The patch contains about 200 Weeping Myall trees. The patch occurs at Jerry's Plains, including the cemetery (Benson in prep.). None of this ecological community exists in protected areas (Benson in prep.).

The Weeping Myall that dominates this ecological community is disjunct from the major occurrences on the Liverpool Plains, 100 km to the west. It is probably a relic from the last ice age when the Hunter Valley would have been dominated by 'western semi-arid' flora (Benson in prep., T. Tame pers. comm.).

EPBC Act criteria

The TSSC judges the ecological community to be eligible for listing as critically endangered under the EPBC Act. The justification against the criteria is as follows:

Criterion 1 - Decline in geographic distribution

The pre-European distribution of Weeping Myall - Coobah - Scrub Wilga Shrubland of the Hunter Valley is estimated at 100 ha (Benson in prep.). The ecological community is considered naturally rare, a relic of a previous climate regime. The present distribution is two hectares. This constitutes a 98% reduction in geographic distribution.

As the geographic distribution of this ecological community has undergone a severe decline (approximately 98%), it is eligible for listing as critically endangered under this criterion.

Criterion 2 - Small geographic distribution coupled with demonstrable threat

The Weeping Myall - Coobah - Scrub Wilga Shrubland of the Hunter Valley ecological community has a very restricted geographic distribution of approximately 2 hectares. As such, it is vulnerable to human impacts and natural catastrophic events. This ecological community does not occur in any dedicated conservation reserve. Trampling and grazing by animals may reduce germination rates of native species and increase the risk of weed infestation. Weed infestation of the ecological community is currently moderate (5-15%). Firewood collection has also been identified as a potential threat (Benson in prep.).

It is considered that sufficient biodiversity remains in the ecological community for natural regeneration if threats are controlled and ecosystem processes reinstated (Benson in prep).

As this ecological community has a very restricted distribution, and is subject to threatening processes, it is eligible for listing as critically endangered under this criterion.

Criterion 3 - Loss or decline of functionally important species

There is no information addressing this criterion for Weeping Myall - Coobah - Scrub Wilga Shrubland of the Hunter Valley. Therefore, this ecological community is not eligible for listing under this criterion.

Criterion 4 - Reduction in community integrity

There is no information addressing this criterion for Weeping Myall - Coobah - Scrub Wilga Shrubland of the Hunter Valley. Therefore, this ecological community is not eligible for listing under this criterion.

Criterion 5 - Rate of continuing detrimental change

There is no information addressing this criterion for Weeping Myall - Coobah - Scrub Wilga Shrubland of the Hunter Valley. Therefore, this ecological community is not eligible for listing under this criterion.

Criterion 6 - Quantitative analysis showing probability of extinction

There is no information addressing this criterion for Weeping Myall - Coobah - Scrub Wilga Shrubland of the Hunter Valley. Therefore, this ecological community is not eligible for listing under this criterion.

5. Conclusion

The Weeping Myall - Coobah - Scrub Wilga Shrubland of the Hunter Valley ecological community meets Criterion 1 as critically endangered as it has undergone a very severe decline, and Criterion 2 as critically endangered as its geographic distribution is very restricted and is coupled with ongoing demonstrable threat.

6. Recommendation

TSSC recommends that the list referred to in section 181 of the EPBC Act be amended by including in the list in the critically endangered category: 'Weeping Myall - Coobah - Scrub Wilga Shrubland of the Hunter Valley'.

Table 1. Characteristic native plant species of the Weeping Myall - Coobah - Scrub Wilga Shrubland of the Hunter Valley ecological community. Not every species may be present at all times. This list is not comprehensive, and does not include all plant species found in the ecological community.
Type Scientific name Common name
Trees Acacia pendula Weeping Myall, Boree, Myall
Shrubs/Vines/Epiphytes Geijera salicifolia Scrub Wilga, Green Satinheart, Glasswood, Greenheart, Flintwood, Axegapper, Brush Wilga
Acacia salicina Coobah, Cooba, Broughton Willow, Australian Willow, Native Willow
Myoporum montanum Water Bush, Western Boobialla
Geijera parviflora Wilga, Greenheart, Native Willow
Canthium buxifolium Stiff Canthium, Shiny Canthium
Acacia omalophylla Yarran, Yarran Wattle
Groundcover Themeda australis Kangaroo Grass
Poa sieberiana Grey Tussock-grass, Poa Tussock
Austrodanthonia bipartita Wallaby Grass, Leafy Wallaby Grass
Cymbopogon refractus Barbed-wire Grass
Bothriochloa macra Red-leg Grass, Redgrass
Chrysocephalum semipapposum Clustered Everlasting
Spartothamnella juncea Red Bead Bush, Square-stemmed Broom
Einadia nutans subsp. nutans Nodding Saltbush, Climbing Saltbush

Publications used to assess the nomination

Benson, J.S. (in prep.) New South Wales vegetation classification and assessment database, Royal Botanic Gardens and Domain Trust, Sydney.

Tame, T. (1992) Evolution of the Hunter Valley, Hunter Natural History 50.

Conservation Advice

The Weeping Myall - Coobah - Scrub Wilga Shrubland of the Hunter Valley is very restricted, occurring as a single two hectare patch in the Hunter Valley, NSW.

The priority recovery and threat abatement actions required for this ecological community are:

  • facilitate a conservation agreement for this site;
  • management and control of weeds;
  • restrict access to the ecological community for firewood collection or recreation.

This list does not encompass all actions that may be of benefit to this ecological community, but highlights those that are considered to be of the highest priority at the time of listing.

Priority for the development of recovery plan: low