New England Peppermint Grassy Woodland

New England Peppermint Grassy Woodland is the name given to the threatened ecological community dominated by New England peppermint (Eucalyptus nova-anglica). Other eucalypt species that may co-dominate in this community include Snow gum (Eucalyptus pauciflora) and Mountain gum (Eucalyptus dalrympleana subsp. heptantha). The understorey is characterised by a dense and often diverse mix of native grasses and herbs.

This community grows at high altitudes on valley flats and lower slopes. It has a relatively restricted range found primarily in the New England Tablelands Bioregion of north eastern New South Wales and Southern Queensland.

New England Peppermint Grassy Woodland provides valuable habitat for a range of native birds, bats, reptiles, frogs and mammals. Several threatened flora and fauna species, such as the Austral toadflax (Thesium australe) and Swift parrot (Lathamus discolor) may be found living in this woodland.

Unfortunately, large areas of New England Peppermint Grassy Woodland have been cleared. Remaining patches of woodland are small (often <10ha) and highly fragmented. It is listed as a threatened ecological community under both the Australian Government's Environment Protection and Biodiversity Conservation Act 1999 (EPBC Act) and the NSW Threatened Species Conservation Act 1995 (TSC Act).

Activities which affect the condition or extent of New England Peppermint Grassy Woodland may require consent or approval.

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Where does the community occur?

In the Border Rivers-Gwydir catchment New England Peppermint Grassy Woodland occurs on the tablelands on the eastern edge of the catchment.

Specifically, New England Peppermint Grassy Woodland occurs or is predicted to occur within the following IBRA subregions of the Border Rivers and Gwydir catchments: Bundarra Downs, Deepwater Downs, Glen Innes-Guyra Basalts, Moredun Volcanics, Northeast Forest Lands, Tenterfield Plateau and Yarrowyck-Kentucky Downs (www.environment.gov.au/parks/nrs/science/pubs/subregions.pdf).

Identification

New England Peppermint Grassy Woodland has a woodland or open forest structure. The density of the tree canopy ranges from less than 30% coverage in a woodland, and up to 50% in an open forest. The canopy is dominated (>50% of the canopy) or co-dominated (>30% of the canopy) by New England peppermint (Eucalyptus nova-anglica) and ranges in height from 8-20 m.

Tree species that may co-dominate in this community include Snow gum (Eucalyptus pauciflora) and Mountain gum (E. dalrympleana subsp. heptantha). Other species that may be present in the community include Black sallee (E. stellulata), Blakely’s red gum (E. blakelyi), Narrow-leaved peppermint (E. radiata subsp. sejuncta) and Candlebark (E. rubida).

This community typically lacks a substantial shrub layer. A sparse layer of shrubs may occur and may include the following species: Silver wattle (Acacia dealbata), Blackthorn (Bursaria spinosa), Sharp beard-heath (Leucopogon fraseri), Peach heath (Lissanthe strigosa), Urn heath (Melichrus urceolatus) and Native raspberry (Rubus parvifolius).

The ground layer is typically a dense cover of grasses and herbs. Cover and species composition of the ground layer can vary considerably depending on climatic conditions, past management and disturbance events. Common grasses are Snowgrass (Poa sieberiana) and Kangaroo grass (Themeda australis).

The community has suffered extensive tree decline due to dieback and may occur in some areas only with an intact ground layer. In this situation the community may be described as a Derived Native Grassland and may still have the capacity to be restored to woodland.

Where is it found?

New England Peppermint Grassy Woodland is found on public and private land. Some of the best patches of this woodland are found in Travelling Stock Reserves.

The community occurs at elevations between 900-1400 m where it grows on valley flats and lower slopes subject to cold air drainage. It is found on both poorly drained fertile soils derived from basalt, sediments and rhyolite as well as coarse sandy soils on granite.

What is not New England Peppermint Grassy Woodland?

Woodland with >70% of the total canopy cover dominated by any eucalypt other than New England peppermint is not part of the protected community. New England peppermint should comprise at least 30% of the total canopy cover.

While all remnants of New England Peppermint Grassy Woodland are valuable, only those in good condition are protected under the EPBC Act. Several condition thresholds must be met for a patch to be protected under the EPBC Act:

  • The patch must be at least 0.5 ha in size
  • 50% or more of the perennial ground cover must be made up of native species
  • The ground cover must have either at least 20 native vascular species or at least 5 different grazing-sensitive (highly palatable) species present
  • At least 10 native trees per 0.5 ha that are at least 10 cm in diameter at breast height; OR at least 10 native tree stems per 0.5 ha that are at least 50 cm in height, as evidence of potential natural regeneration of native tree species

Threats

New England Peppermint Grassy Woodland communities are threatened with continued decline and possible extinction from both historical and current sources. It is estimated that since European settlement 90% of the community occurring on basaltic and sedimentary substrates and 70% on granitic substrate has been cleared. Clearing was primarily for the establishment of developed pastures. Since the late 1970s dieback has caused substantial tree decline.

Intensified land use – practices including pasture development and fertiliser application can degrade the native understorey of the community and may also contribute to dieback.

Vegetation clearing – the community generally occurs on flat or relatively fertile land that is favoured for pastures, rural residential developments, infrastructure works and maintenance.

Dieback – dieback describes a process whereby a tree's crown progressively deteriorates. A major causal factor on the New England Tablelands is outbreaks of leaf eating insects. Insect pressures have increased with land use practices such as developed pasture and fertiliser application. Fragmentation and a decline in insectivores have reduced the community's ability to survive or recover from insect attack.

Weed invasion – exotic plants pose a major threat to the integrity of this community. Highly invasive environmental weeds such as Coolatai grass (Hyparrhenia hirta), African lovegrass (Eragrostis curvula), Serrated tussock (Nassella trichotoma) and St John's wort (Hypericum perforatum) can invade and dominate the understorey of undisturbed remnants. Exotic shrubs such as Hawthorn (Crataegus monogyna) and Pyracantha (Pyracantha angustifolia) can change the natural structure of the community and displace native species.

Inappropriate grazing regimes – overgrazing can lead to reduced plant diversity through the removal of the most palatable species. Grazing of young tree saplings may prevent the overstorey from successfully regenerating. Trampling from stock may lead to soil compaction, reduced water infiltration, reduced seed germination and weed infestation.

Fragmentation into small remnants – most of the remaining remnants of this community are less than 10 hectares in size and isolated from other remnants. Many plants and animals require an area larger than this to successfully reproduce and thrive. Small remnants also have a high edge to size ratio, making them vulnerable to weeds, pests, spray drift and climatic extremes.

Changes in hydrology – as the community occurs in valley floors changes to local drainage can impact on the community. Deeply eroded gullies have lead to water logging in some sites.

Climate change – has the potential to reduce the already restricted geographical distribution of this community. It may also increase the impact of other threats such as dieback and weeds.

Management

The aim of management of New England Peppermint Grassy Woodland is to maintain or increase the extent of the community and to maintain or improve its condition.

  • It is recommended that you do not clear stands of woodland, even under permissible exemptions from the Native Vegetation Conservation Act.
  • Provide long-term protection for the community through agreements with the CMA or through Conservation Agreements with the Office of Environment and Heritage or the Nature Conservation Trust.
  • Re-establish woodland sites through revegetation and assisted regeneration. Revegetation should aim to reconnect fragmented stands or to expand the size of existing stands to at least 1 hectare.
  • Control weeds within and around existing woodland. Repeated treatments will probably be needed.
  • Avoid creating disturbance that will spread or allow weeds to establish. If Coolatai grass is present avoid burning.
  • If native tussocks are very large or dense use mowing, grazing or ecological burns to create inter-tussock spaces for regeneration of native herbs.
  • Fence existing stands and exclude domestic livestock. Occasional light grazing may be sustainable if natives are not flowering or seeding.
  • Identify and control feral animals, particularly rabbits.
  • Note the extent of grazing by native animals and obtain permits for control if necessary.
  • Do not cultivate or apply fertiliser within this community.
  • If establishing exotic pastures nearby, maintain a wide (500 m) buffer of native pasture around remnant stands to minimise direct edge-effect pressures.
  • Retain all fallen timber and leaf litter within remnant stands as these are important habitat for native wildlife.

Ecosystem function: how healthy woodlands work for you

Healthy New England Peppermint Grassy Woodlands provides a wide range of benefits that are called 'ecosystem services'. These include traditional services like grazing for livestock, but also other services such as:

  • capture of solar energy
  • soil formation and cycling
  • nutrient cycling
  • water capture, filtration and delivery to water bodies
  • pollination
  • pest management (e.g. reducing pest pressure on crops)
  • regional climate buffering
  • shade and shelter (e.g. for livestock)
  • breakdown and absorption of wastes
  • a sense of place
  • scenery

Further Information

Look for "New England Peppermint Grassy Woodland" on the Australian Government Threatened Species and Ecological Communities website:
http://www.environment.gov.au/biodiversity/threatened/index.html

The listing for this community under the NSW Threatened Species Conservation
Act can be found at:
http://www.environment.nsw.gov.au/threatenedSpeciesApp/profile.aspx?id=10558

 

Contact the Border Rivers-Gwydir Catchment Management Authority at
02 6728 8020 or visit our website at http://www.brg.cma.nsw.gov.au

 

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