Temperate Highland Peat Swamps on Sandstone

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)
May 2005

1. Name

Two nominations were submitted for peat swamps on sandstone sediments in the highlands of temperate eastern Australia:

  • Blue Mountains Swamps; and
  • NSW Southern Highlands Montane Peat Swamps.

Other temperate peat swamps on sandstone were identified by experts as being alike to the peat swamps identified in the above nominations.

Due to the similarity of the two nominated ecological community components and the additional components identified by experts, it is recommended that they be assessed as a national ecological community: Temperate Highland Peat Swamps on Sandstone.

2. National Context

The formation of wetlands, including peat swamps, is dependent on a number of factors, such as location in the landscape and total catchment area. The vegetation comprising the wetland is also variable, depending on a range of factors that include surface water flow, altitude, and rainfall. The specific geology underlying each wetland also plays an important role in the formation of ecological communities, as soils derived from different parent rocks have differing structures and levels of fertility.

Peat formation on sandstone is recognised as being unusual. Sandstone erodes easily, generally forming deep valleys with fast flowing streams. As such, the broad, shallow, slow flowing streams which produce the conditions necessary for the formation of peat depositions, are unusual on sandstone sediments. Also, the highly erodible nature of sandstone results in a high sediment load that generally overwhelms and buries the organic deposition that forms the swamp.

Two nominations were received for highland (between 600-1100 m asl) peat swamps on the Southern Tablelands. The swamps identified in these two nominations were separately described as being identifiable due to the underlying geology, which is generally sandstone. Due to the similarities in geology, vegetation, and level of threat to these components, it is proposed that they be considered as one national ecological community.

Because the two nominations identified temperate highland peat swamps on sandstone, additional components of this ecological community could be identified through consultation with experts. The components of the Temperate Highland Peat Swamps on Sandstone ecological community are:

  • Blue Mountains Swamps
  • Butler's Swamp
  • Jackson's Bog (Mila Swamp)
  • Newnes Plateau Swamps
  • Paddy's River Swamps - Hanging Rock, Long, Mundego and Stingray Swamps
  • Wildes Meadow Swamp
  • Wingecarribee Swamp

The altitude and location of these components of the Temperate Highland Peat Swamps on Sandstone ecological community are shown in Table 1.

Table 1. Name and location of individual components of The Temperate Highland Peat Swamps on Sandstone ecological community
Name Altitude (m above sea level) Location:
latitude
longitude
Land tenure
Blue Mountains Swamps 800-950 Blue Mountains - based around 33º40'
150º30'
Freehold;
National Park
Butler's Swamp 620 34º31'30"
150º35'20"
Crown land;
Freehold
Jackson's Bog (Mila Swamp) 780 37º07'
149º09'
Freehold;
State Forest
Newnes Plateau Swamps 1000-1100 33º20' to 33º23'
150º12' to 150º15'
State Forest
Paddy's River Swamps
(Hanging Rock, Mundego, Long and Stingray Swamps)
600-650 34º36' to 34º41'
150º07' to 150º15'
Flora Reserve;
Freehold;
State Forest
Wildes Meadow Swamp 670 34º37'30"
150º30'30"
Crown land
Wingecarribee Swamp 680 34º34'
150º30'
Crown land;
Freehold

3. Description

Components of the Temperate Highland Peat Swamps on Sandstone ecological community are either temporary or permanent swamps. These swamps are found in a range of locations in the landscape, from hanging swamps in the Blue Mountains to the valley and watercourse swamps of Wingecarribee Swamp and the Paddy's River Swamps. Hanging swamps are especially notable in the landscape as they occur on steep valley sides in wet areas created by water exiting the ground at joins between sandstone and claystone layers of rock. The other swamps in this ecological community occur in depressions in the landscape, or along watercourses.

The location of the Temperate Highland Peat Swamps on Sandstone ecological community in the landscape plays an important role in determining the level of waterlogging and the amount of sedimentation that occur in the swamps. Hanging swamps have low levels of sedimentation, and accumulate organic material slowly, while valley swamps and those along watercourses have greater levels of sedimentation, and accumulate organic material more quickly. The difference in the accumulation of organic material is important for the depth of the peat on which these swamps are based: shallow in the hanging swamps and deep in the swamps on valley floors.

The interaction of location, waterlogging, sedimentation, and fire history impact on the vegetation found within the various components of the Temperate Highland Peat Swamps on Sandstone ecological community. The vegetation associated with this ecological community is a complex patchwork of vegetation types, and varies from bog and fen associations in the wettest parts of some components, through to sedge associations, and shrub associations in the driest parts of the ecological community. A list of plant species that are likely to occur in components of the Temperate Highland Peat Swamps on Sandstone ecological community is shown in Table 2.

Table 2. Native plant species likely to be found in the components of the Temperate Highland Peat Swamps on Sandstone ecological community. This list is not exhaustive, and the plants listed will not occur in every component
Vegetation type Species name Common name(s)
Mosses Sphagnum spp. Sphagnum Moss
Ferns Blechnum spp.
Gleichenia microphylla
Todea barbara

Scrambling Coral-fern, Coral-fern, Umbrella Fern
King Fern
Herbs Cryptostylis sp.
Microtis spp.
Prasophyllum uroglossum
Spiranthes sinensis
Thelymitra pauciflora
Viola betonicifolia


Wingecarribee Leek-orchid, Dark Leek-orchid
Austral Ladie's Tresses
Slender Sun-orchid, Few-flowered Sun-orchid
Showy Violet, Arrow-head Violet
Sedges Carex spp.
Chorizandra cymbaria
Cyperus
spp.
Eleocharis spp.
Empodisma minus
Gahnia
spp.
Gymnoschoenus sphaerocephalus
Isolepis
spp.
Juncus spp.
Lepidosperma limicolum
Leptocarpus tenax
Lepyrodia scariosa
Luzula modesta
Ptilothrix deusta
Schoenus apogon

Bristle Rush


Spreading Rope Rush

Button Grass







Fluke Bogrush
Grasses Deyeuxia quadriseta
Dichelachne inaequiglumis
Hemarthria uncinata
Isachne globosa
Phragmites australis
Poa labillardierei
var. labillardierei

Plume Grass
Mat Grass
Swamp Millet
Common Reed
Tussock Grass
Heaths Epacris microphylla
Epacris obtusifolia
Epacris paludosa
Epacris
spp.
Coral Heath

Swamp Heath
Shrubs Baeckea linifolia
Banksia spinulosa
Callistemon citrinus
Dillwynia sericea
Grevillea acanthifolia
Hakea
spp.
Leptospermum spp.
Pultenaea spp.
Swamp Baeckea
Hairpin Banksia, Hill Banksia
Crimson Bottlebrush
Showy Parrot-pea
Spiny-leaved Grevillea

EPBC Act criteria

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

Criterion 1 - Decline in geographic distribution

Two of the components of the Temperate Highland Peat Swamps on Sandstone ecological community have undergone a significant change in their extent: Wingecarribee Swamp has been reduced from an original extent of 690 ha to approximately 310 ha; and Wildes Meadow Swamp has been reduced to approximately 10% of its original extent, and now covers only 33 ha. However, as there is little data on the original extent of all components of this ecological community, no assessment can be made against this criterion. Therefore, The Temperate Highland Peat Swamps on Sandstone ecological community is not eligible for listing under this criterion.

Criterion 2 - Small geographic distribution coupled with demonstrable threat

Swamps have a naturally restricted occupancy within the landscape, generally along water courses or around wet areas of natural groundwater discharge. The Temperate Highland Peat Swamps on Sandstone ecological community has a small geographic distribution, totalling approximately 3000 ha. Of this total area, approximately 1300 ha is reserved in the Blue Mountains National Park, with the rest in a mix of freehold, State forests and Crown land.

Given the location of swamps in the landscape and their dependency on water, they are susceptible to changes in water flow, level of the water table, and structural damage. Several of the components of the Temperate Highland Peat Swamps on Sandstone ecological community have been degraded through alterations to water flows and a change to the level of the watertable. For example:

  • Wingecarribee Swamp has had between 30-50% of its area flooded by an impoundment of the Wingecarribee River;
  • Over 90% of Wildes Meadow Swamp has been lost as a consequence of construction of the Fitzroy Falls reservoir, followed by draining of a majority of the remaining swamp areas;
  • The northern (upstream) section of Jackson's Bog has been modified by an artificial drain in the central area of the swamp which has resulted in a lowered watertable, and a subsequent change in vegetation from a sedge-based association to a wet tussock grass association; and
  • The vegetation surrounding Stingray Swamp was cleared in the past for pine plantations, which are now themselves being clear felled.

These alterations to the water flow and level all impact on the vegetation associations within the ecological community, as well as impacting on the peat substrate on which the ecological community is based.

Nearly all of the components of the Temperate Highland Peat Swamps on Sandstone ecological community have been affected by physical disturbance caused by introduced animals. The introduced animals identified from components of the Temperate Highland Peat Swamps on Sandstone ecological community include cattle, horses, rabbits, foxes, pigs, cats and dogs.

Cattle enter the waters of the swamps to feed and drink, especially in dry weather, and in components that have not been impounded, domestic stock are frequently let loose to graze on the vegetation of the swamp. The damage caused by cattle includes altered grazing regimes, and trampling. Trampling is damaging to the vegetation and underlying peat as it can destroy the sub-surface portions of the vegetation, thereby reducing regeneration of the affected plants. Trampling and grazing can result in patches of erosion.

Feral pigs have been observed in at least one component of the Temperate Highland Peat Swamps on Sandstone ecological community. Feral pigs damage the swamp by wallowing, causing extensive damage to vegetation.

Introduced animals disperse weeds throughout the ecological community by consuming then excreting the seeds. The damage from this is observed when introduced pasture grasses and herbs become naturalised in the swamps and compete with native vegetation.

Another form of disturbance, peat mining, is more damaging to the structure and stability of the Temperate Highland Peat Swamps on Sandstone ecological community than that caused by domestic and feral animals. For example:

  • Peat mining in the Wingecarribee Swamp after the impoundment of the lower portion, may have contributed to the collapse of the peat in the remainder of the swamp that has reduced the area of the swamp to approximately 25% of its original extent. The swamp is now a fragmented and highly-incised system with water being channelled between the peat sections, rather than flowing in a broad front throughout the peat. This has resulted in a lower water table, which negatively impacts the remaining sections and fragments of the component; and
  • Long Swamp extends for approximately 5 kilometres along the length of Long Swamp Creek. This component of the Temperate Highland Peat Swamps on Sandstone ecological community has been mined for peat for over 10 years.

The reservation of approximately 40% of this ecological community in the Blue Mountains National Park provides some protection for those components of the Temperate Highland Peat Swamps on Sandstone ecological community in the National Park. However, even within the National Park, the sensitivity of the ecological community to disturbance leaves all components of the ecological community at risk from changes in the environment upstream of the swamp. For example, the creation of roads and tracks (including walking) upstream from swamps increases the inorganic sediment load in the swamps. If the rate of sedimentation is sufficiently high, or sustained over a prolonged period, it will smother the vegetation in the swamp, raise the surface above the watertable, and ultimately result in a different ecological community.

Components of the Temperate Highland Peat Swamps on Sandstone ecological community that occur in urban areas are susceptible to additional threats from increased nutrient load, residential development, clearing, greater chance of invasion by weeds, groundwater extraction, and inappropriate fire regimes.

Temperate Highland Peat Swamps on Sandstone is an ecological community that has a restricted natural occurrence, and threats to this ecological community are present and ongoing from a number of sources. Therefore, the ecological community is eligible for listing as endangered under this criterion.

Criterion 3 - Loss or decline of functionally important species

No information was available regarding the loss of functionally important species for this ecological community. Therefore, the ecological community is not eligible for listing under this criterion.

Criterion 4 - Reduction in community integrity

Although there is information on the decline of the peat sediment in specific components of the Temperate Highland Peat Swamps on Sandstone ecological community, no detailed information is available on the reduction in the integrity of the ecological community. Therefore, the ecological community is not eligible for listing under this criterion.

Criterion 5 - Rate of continuing detrimental change

There is information available to identify that detrimental change is occurring to this ecological community, but it is not sufficient to enable a rate of change to be estimated. Therefore, the ecological community is not eligible for listing under this criterion.

Criterion 6 - Quantitative analysis showing probability of extinction

No information is available to address this criterion. Therefore, the ecological community is not eligible for listing under this criterion.

5. Conclusion

The Temperate Highland Peat Swamps on Sandstone ecological community meets criterion 2 as endangered as it is restricted in its geographic distribution and is subject to demonstrable and ongoing threats.

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 endangered category:

  • Temperate Highland Peat Swamps on Sandstone

Associate Professor Robert J.S. Beeton
Chair, Threatened Species Scientific Committee

Publications used to assess the nomination

Benson, D. H. 1978. Native Vegetation of the Newnes Plateau. Report to the NSW Department of Agriculture.

Environment Australia. 2001.A Directory of Important Wetlands. Third Edition. Environment Australia, Canberra.

Kodela, P. G. and Hope, G. S. 1992. Wingecarribee Swamp: statement of significance. National Trust of Australia (New South Wales), Sydney.

Kodela, P. G., James, T. A. and Hind, P. D. 1994. Observations on the ecology and conservation status of the rare herb Gentiana wingecarribiensis. Cunninghamia 3: 535-541.

Murray, M. and Winning, G. 1993. Review of Literature on High Country Wetlands of New South Wales and Victoria. An addition to the Directory of Important Wetlands in Australia. Report to Australian Nature Conservation Agency.

Stricker, J. and Stroinovsky, N. 1995. Wingecarribee Swamp. A natural and cultural history. Sydney Water Corporation.

Winning, G. and Brown, S. 1994. South Coast Wetlands Survey. Literature Review. Parts A and C. Report to NSW Department of Water Resources and Australian Nature Conservation Agency.

Conservation Advice

The Temperate Highland Peat Swamps on Sandstone is an ecological community of temporary or permanent swamps. The ecological community is confined to New South Wales, and comprises particular swamps in the Blue Mountains, Lithgow, Southern Highlands and Bombala regions. These peat swamps share a similar geology and vegetation. They are found in a range of locations in the landscape, from hanging swamps to valley and watercourse swamps. Only 3000 hectares of the Temperate Highland Peat Swamps on Sandstone remain. About 1300 hectares occur within the Blue Mountains National Park with the remainder on a mixed tenure of freehold, State forests and Crown land.

Nearly all of the swamps that comprise this ecological community have been badly affected by introduced animals, including cattle, horses, rabbits, foxes, pigs, cats and dogs. Those swamps that occur in urban areas are also at risk from increased fertiliser runoff, residential development, clearing, weeds and fire. Peat mining has also been a threat to some swamps.

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

  • develop conservation agreements or covenants with landholders who have the swamps on their properties;
  • fence important remnants to control the impacts of certain introduced animals;
  • identify seasonal and long-term fluctuations in the water flows and water quality regimes within the swamps;
  • minimise impacts from changes to water flow and water quality;
  • manage weeds within and immediately adjacent to existing remnants; and
  • rehabilitate degraded remnants with local species, which are known to occur in these specific environments.

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.

Development of a recovery plan: High priority.