Threatened species & ecological communities

Tetratheca juncea

Advice to the Minister for the Environment and Heritage from the Threatened Species Scientific Committee (TSSC) on Amendments to the list of Threatened Species under the Environment Protection and Biodiversity Conservation Act 1999 (EPBC Act)
7 September 2005
(species listed on 16 July 2000)

Contents

1. Scientific name, common name (where appropriate), major taxon group

Tetratheca juncea. This species has no common name.

2. Description

Tetratheca juncea is a low growing, usually leafless shrub with clumps of stems to 1 m or more in length that bear deep lilac-pink or rarely white flowers. When present, the narrow leaves are about 2 cm long and lack a stalk (Thompson 1976, Harden 1992, Payne 2000). Tetratheca juncea occurs largely in coastal and subcoastal areas. It usually grows in low nutrient soils on hills and ridges and along creeks, and is associated with woodland and open forest dominated by various species of Eucalyptus and other tree species, or with heath vegetation.

3. National context

Tetratheca juncea occurs naturally only in New South Wales. Historical records indicate that Tetratheca juncea once occurred in disjunct populations from Bulahdelah south to the Sydney region from suburbs including Carlton, Kogarah, Bexley and Undercliff (Payne 1993, based on herbarium collections). The Sydney subpopulation/s are now believed to be locally extinct (Benson and Howell 1990 cited in Payne 2000, Harden 1992, Resource and Conservation Assessment Council undated).

Today the species is restricted to the North Coast and Central Coast botanical regions of New South Wales (Harden 1992). Extant populations are located from Bulahdelah in the north to the Wyong area in the south, extending inland as far as Maitland and Kurri Kurri (Harden 1992, Payne 1993, Payne 2000, Resource and Conservation Assessment Council undated). Most populations occur in the Wyong and Lake Macquarie local government areas, with isolated populations present in the Cessnock, Newcastle, Port Stephens and Great Lakes local government areas (Payne 2000).

Tetratheca juncea is listed as vulnerable in New South Wales under the Threatened Species Conservation Act 1995. This conservation status was reviewed on behalf of the New South Wales Scientific Committee in December 2002 with the species considered to be appropriately listed as vulnerable (Hogbin 2002a) based on IUCN criteria B and C (Hogbin 2002b). This assessment was based on the species' restricted area of occurrence and low number of mature individuals, combined with the fragmented nature of the total population and predicted declines in habitat quality and extent (Hogbin 2002b).

Recovery actions reported by the New South Wales National Parks and Wildlife Service for Tetratheca juncea include habitat protection, fencing and site protection, habitat restoration and translocation of plants (NSW NPWS 2003d). Fire management is specifically aimed at protecting Tetratheca juncea in Munmorah State Recreation Area, with autumn to summer fires of moderate to high intensity considered desirable for the species (NSW NPWS 2003c).

4. How judged by TSSC in relation to the EPBC Act criteria.

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

Criterion 1 - Decline in numbers

Tetratheca juncea was formerly collected from between Botany Bay and Broken Bay in the Sydney district, but is now considered extinct in that area. This local extinction would have reduced the species' linear range from approximately 200 to 110 km (DEH 2004b, Payne 2000) and the species is likely to have been reduced in total population size as a result.

The main threats to Tetratheca juncea are considered to be habitat loss and degradation associated with land development (e.g. Great Lakes Council 2003, Karuah-Great Lakes Catchment Management Committee 2001, Lake Macquarie Council 2003, Lake Macquarie Council 2004, Payne 1993, Wyong Shire Council 2003) and coal mining (Bartier 2001) although some developments have been shown likely to affect only a small proportion of plants in a given area (HWR Ecological 2002).

Weeds, which presumably compete with Tetratheca juncea plants for light and water, and may smother plant clumps, have been reported to be a potential threat in some areas (NSW NPWS 2003b) including the Wyong area (Wyong Shire Council 2003). Payne (2000) noted that invasion by weed species such as Blady Grass and Bracken may be encouraged by inappropriate fire regimes. Timber harvesting and inappropriate fire regimes are also considered threats to the species (Karuah-Great Lakes Catchment Management Committee 2001, NSW NPWS 2003b, Payne 1993, 2000, Wyong Shire Council 2003).

Many of the subpopulations reported in 2000 were located on private property or rural land that could be redeveloped in the future (Payne 2000). Payne (2000) noted that urbanisation, the presumed cause of extinction of subpopulations in the Sydney area, was occurring extensively in the Wyong and Lake Macquarie local government areas. Subpopulations associated with hill top locations, such as in the Munmorah area, are considered to be highly susceptible to infrastructure development (roads, quarries, spoil heaps) and residential development and services, as well as more frequent fire (Payne 1993). Since 2000, infrastructure development and land development (including rural residential subdivisions) are known to have occurred in areas where the species was located.

Payne (2000) notes that the species appears sensitive to soil disturbance and vegetation clearance. Development activities involving clearing are likely to adversely affect the species through destruction of plants, loss/alteration of habitat, increasing fragmentation of subpopulations, and loss of connectivity between subpopulations. Where portions of subpopulations are retained and incorporated into residential design (Conacher Travers 2003, Lake Macquarie Council 2004), plants may still be at risk, for example from rubbish dumping (Wyong Shire Council 2003) or local recreational activities. Phytophthora cinnamomi has been declared a key threatening process in NSW (NSW Scientific Committee 2003) with Tetratheca juncea being listed as a species with the potential to be adversely affected either through direct infestation or habitat degradation.

In 2000, approximately 17% of the total clump population was considered to be located in state conservation areas. The most recently reported 'best estimate' of total population size is between 9881 and 11 893 plant clumps (Hogbin 2002b) with Payne reporting approximately 9645 plant clumps (Payne 2000). Hogbin's estimates covered more than 240 sub-populations known in 2002, and were based on data reported from field surveys and accounting for possible errors where the number of stems exceeded 50 per plant (Hogbin 2002b). 83% of the known subpopulations are considered to support fewer than 50 individuals.

Data on changes in subpopulations of Tetratheca juncea at specific locations are available for only a small number of subpopulations. There is insufficient information available to indicate that Tetratheca juncea has undergone, or is suspected to have undergone a very severe, severe or substantial reduction in numbers. In addition, while a number of potential threats have been identified, Tetratheca juncea is unlikely, in the immediate future, to undergo at least a substantial reduction in numbers (i.e. greater or equal to 30%).

Therefore, the species is not eligible for listing under this criterion.

Criterion 2 - Geographic distribution

Tetratheca juncea is severely fragmented. Detailed surveys by Payne (2000) revealed approximately 239 locations or subpopulations of Tetratheca juncea, with later estimates indicating the species was known from 250 locations or subpopulations (Payne cited in Bartier et al. 2001). Of the 239 subpopulations reported by Payne (2000), 83% contained 50 or fewer plant clumps. Only 22 subpopulations (9.5%) contained 100 or more plant clumps, of which only four subpopulations contained between 401 and 1500 plant clumps. At least four subpopulations (Green Point Recreation Reserve, Awaba Interchange, Jewells/Red Head and Glenrock State Recreation Area) are considered to contain more than 1000 plant clumps (Payne 2000, Lake Macquarie City Council unpublished information 2004).

DEH (2004a) used BIOCLIM to estimate the potential distribution of Tetratheca juncea. This distribution was used as a surrogate for the species' extent of occurrence because the modelled distribution closely aligns with known locations of the species. The estimate based on DEH (2004a) and that of Hogbin (2002b) suggest the species has an extent of occurrence of between 1 94 km2 (DEH 2004a) and 1861 km2 (Hogbin 2002b). These estimates appear to cover all subpopulations located during detailed surveys by Payne (2000) and populations found subsequently (Payne, cited in Bartier et al. 2001).

Because of the large number of locations at which Tetratheca juncea occurs within its current range, continued local extinctions resulting from activities such as land development would appear unlikely to result in major declines to the species' current extent of occurrence (Purdie 2004). The total area of occupancy of the species is not known (Hogbin 2004). There appears to be potential for the species' area of occupancy to decrease through the loss of populations at locations subject to future land development. For some developments only small reductions have been estimated for specific subpopulations (Conacher Travis 2003). No data is available on natural fluctuations in the extent of occurrence or area of occupancy of Tetratheca juncea.

In 2000, 45 of 239 known subpopulations were located in state conservation areas (Munmorah State Recreation Area, Lake Macquarie State Recreation Area, Awabakal Nature Reserve, Glenrock Nature Reserve) comprising approximately 1600 plant clumps or approximately 17% of the total clump population (Payne 2000). Other subpopulations were contained in council reserves (Payne 2000). Subpopulations are now also reserved in Wallarah National Park (Conacher Travis 2003), Wallaroo and Karuah Nature Reserves (McCarthy 2002) and Greenpoint Recreation Reserve (Gross et al. 2003). Tetratheca juncea is also considered likely to be present in Pulbah Island Nature Reserve (NSW NPWS 2003e). While fire is used as an active management tool to promote Tetratheca juncea in Munmorah State Recreation Area (NSW NPWS 2003c), no information was obtained on the extent to which the other reserves are actively managed to protect the species.

Tetratheca juncea has a small extent of occurrence (estimated to be between 1594 and 1861 km2) and is severely fragmented (i.e. most individuals are found in small and relatively isolated subpopulations). The species is known to consist of approximately 239 subpopulations with 83% of these subpopulations consisting of fewer than 50 individuals. Tetratheca juncea occurs in coastal areas subject to high population growth and associated land development pressures. Most subpopulations occur in the Wyong and Lake Macquarie local government areas, with isolated populations present in the Cessnock, Newcastle, Port Stephens and Great Lakes local government areas (Payne 2000).

Tetratheca juncea has a limited geographic distribution that is precarious for the survival of the species. The species has a restricted extent of occurrence, is severely fragmented, and is subject to ongoing loss and fragmentation of habitat and a continuing decline in the number of subpopulations.

Therefore, the species is eligible for listing as vulnerable under this criterion.

Criterion 3 - Population size and decline in numbers or distribution

The total population size of Tetratheca juncea is difficult to estimate accurately due to the species' habit of clumping. Plant clumps are commonly counted during survey work and used as a surrogate for individual plants. Reports of thousands and possibly tens of thousands of plants (e.g. in the Karuah area) are influenced by the sampling method (HWR Ecological 2002). The total population size of Tetratheca juncea is estimated to be between 9881 and 11 893 plant clumps (approximately 10 000 individuals).

The estimated total number of mature individuals is limited. Given the severely fragmented nature of the species' distribution, and the fact that Tetratheca juncea occurs in coastal areas subject to high population growth and associated land development pressures, it is considered likely that a continuing decline in both the number of subpopulations and individuals is likely to occur.

Therefore, the species is eligible for listing as vulnerable under this criterion.

Criterion 4 - Population size

The total population size of Tetratheca juncea is estimated to be between 9881 and 11 893 plant clumps (approximately 10 000 individuals). While this population size is considered to be limited, the estimated total number of mature individuals is not extremely low, very low or low.

Therefore, the species is not eligible for listing under this criterion.

Criterion 5 - Probability of extinction in the wild

There is no quantitative data available against this criterion. Therefore, the species is not eligible for listing under this criterion.

5. Conclusion

Tetratheca juncea is severely fragmented, consisting of approximately 240 subpopulations with over 80% containing 50 or fewer plant clumps. The total population size of Tetratheca juncea is estimated to be between 9881 to 11 893 plant clumps (approximately 10 000 individuals) and therefore limited. The species' estimated extent of occurrence is restricted, currently being estimated at between 1594 and 1861 km2. The species' total area of occupancy is not known.

Tetratheca juncea has a limited geographic distribution and its habitat is subject to ongoing pressure from land development in the Wyong and Lake Macquarie local government areas. The species' distribution is considered precarious for the survival of the species and it is likely that the species will undergo continuing decline in both the number of its subpopulations and individuals.

The species is eligible for listing as vulnerable under criteria 2 and 3.

6. Recommendation

TSSC recommends that the list referred to in section 178 of the EPBC Act remains unchanged by including in the list in the vulnerable category:

Publications used to assess the nomination

Andrews Neil Architects (1991) Survey of Tetratheca juncea Sm. for the Munmorah to Catherine Hill Bay 33kV Transmission Line servicing Wallarah Colliery, prepared for Shortland Electricity.

Bartier, F. (2001). A Vulnerable Species: Some Mysteries Uncovered. Black & Green Issue 6, Centre for Mined Land Rehabilitation.

Bartier, F., Gross, C.L., Mulligan, D., Bellairs, S. and Bowen, D. (2001). Understanding the biology and ecology of a vulnerable plant species - a case study with Tetratheca juncea occurring over coal leases. ACARP Project C8012. University of Queensland, St Lucia, Queensland. (Cited in Gross et al. 2003.)

Benson, D. and Howell, J. (1990). Taken for granted: the bushland of Sydney and its suburbs. Kangaroo Press in association with the Royal Botanic Gardens, Sydney.

Branwhite, B. (1997). Angophora Inoina Notes.

Briggs, J.D. and Leigh, J.H. (1996). Rare or threatened Australian Plants 1995 rev. edn.

Busby, J.R. (1991). BIOCLIM - a bioclimatic analysis and prediction system. In C.R.Margules and M.P. Austin (eds), Nature conservation: cost effective biological surveys and data analysis, CSIRO, Melbourne, pp 4-68. CHABG (Council of Heads of Australian Botanic Gardens) (1994). Census of plants in botanic gardens, Australian National Botanic Gardens.

Commonwealth of Australia (1999h). Draft Threat Abatement Plan for Dieback caused by the Root-rot fungus (Phytophthora cinnamomi), Commonwealth of Australia.

Commonwealth of Australia (2001). Threat Abatement Plan for Dieback Caused by the Root-rot Fungus Phytophthora cinnamomi. Environment Australia.

Conacher Travers (2003). Ecological assessment, flora and fauna, Stages 1-7 Lake Sector & Village Drive Access Road, Wallarah Peninsula. Vol. 2. Report prepared for Lensworth Wallarah Peninsula Pty Ltd.

DEH (Department of Environment and Heritage) (2003). Hawk Lead-in Fighter, RAAF base Williamstown, NSW - Environment Assessment Report (including Salt Ash Air Weapons Range, Newcastle).

DEH (Department of Environment and Heritage) (2004a). BIOCLIM distribution map of Tetratheca juncea, from Species Profiles and Threats Database, Department of Environment and Heritage, Canberra. Unpublished.

DEH (Department of Environment and Heritage) (2004b). Distribution of Tetratheca juncea (with point locations), from Species Profiles and Threats Database, Department of Environment and Heritage, Canberra. Unpublished.

Great Lakes Council (2003). Supplementary State of the Environment Report 2002/03.

Gross C.L. , Bartier F.V. and D.R. Mulligan (2003). Floral Structure, Breeding System and Fruit-set in the Threatened Sub-shrub Tetratheca juncea Smith (Tremandraceae). Annals of Botany 92, 771-777.

Harden, G.J. (ed) (1992). Flora of New South Wales, Volume 3, p. 76.

Hogbin, T. (2002a). Review of the Threatened Species Conservation Act Flora Schedules: recommendations to the Scientific Committee. Final Summary Report. December 2002.

Hogbin, T. (2002b). Information regarding the current conservation status of Tetratheca juncea Smith. Unpublished material, NSW NPWS.

HWR Ecological (2002). Ecological assessment for proposed highway service centre north of Karuah, Report to GWH Building Pty Ltd. Prepared by Geoff Winning and John-Paul King, version 1.1.

IUCN (2004). Guidelines for using the IUCN Red List categories and criteria, March 2004. Prepared by the Standards and Petitions Subcommittee of the IUCN SSC Red List Programme Committee.

Karuah-Great Lakes Catchment Management Committee (2001). Wallis Lake Catchment Management Plan (Draft), state of the catchment report.

Lake Macquarie Council (2003) Pambulong Forest Area Plan.

Lake Macquarie Council (2004). Development Control Plan No. 45, North Buttaba Hills Estate, Exhibition Draft.

Landenberger, D., Cole, M., Driscoll, C. and MacFarlane, G. (2003). Habitat description and transplantation of Tetratheca juncea. Abstract for ESA Ecology, 2003, conference, Armidale, 8-10 December.

Macquarie Generation URS (2002). Gas fired power station Environmental Impact Statement, chapter 12, Flora and Fauna.

McCarthy, J. (2002). Rare plant species located in Wallaroo and Karuah Nature Reserves. Hunter Flora No.10, page 3.

Meredith, L.D. and Richardson, M.M. (1990). Rare or Threatened Australian Plant Species in Cultivation in Australia, Report Series No. 15, 1-114, ANPWS, Canberra.

Nix, H.A. (1986). A biogeographical analysis of Australian elapid snakes. In R.Longmore (ed), Atlas of elapid snakes of Australia. Australian Flora and Fauna Series Number 7, pp 4-5. Australian Government Publishing Service, Canberra.

NSW NPWS (1997). Glenrock State Recreation Area Plan of Management.

NSW NPWS (2000). Vegetation survey, classification and mapping, Lower Hunter and Central Coast Region. The Lower Hunter and Central Coast Regional Environment Management Strategy.

NSW NPWS (2003b). Weed Management 2003.

NSW NPWS (2003c). Fire management plan Munmorah Conservation Area incorporating Bird Island Nature Reserve.

NSW NPWS (2003d). Saving our threatened native animals and plants. Recovery and threat abatement in action 2003 update.

NSW NPWS (2003e). Lake Macquarie State Recreation Area, Pulbah Island Nature Reserve and Moon Island Nature Reserve Draft Plan of Management.

NSW Scientific Committee (2003). Final determination: infection of native plants by Phytophthora cinnamomi - a key threatening process declaration. NSW National Parks and Wildlfie Service.

Payne, R J (1993). Prediction of the habitat for Tetratheca juncea in the Munmorah area, near Wyong, NSW, Cunninghamia 3(1), 147-154.

Payne, R. (2000). Lake Macquarie Tetratheca juncea Conservation Management Plan, Robert Payne Ecological Surveys & Management. Unpublished report prepared for Lake Macquarie City Council, NSW NPWS and BHP.

Payne (2001). Addendum to the final November 2000 Tetratheca juncea conservation management plan. Lake Macquarie Council & Robert Payne Ecological Surveys and Management.

Purdie, R. (2004). Profile compiler, Centre for Plant Biodiversity Research. Personal observation based on analysis of material compiled for Tetratheca juncea.

Resource and Conservation Assessment Council (RACAC) (undated) Appendix B - Terms of Licence under the Threatened Species Conservation Act - Lower NE Region.

State Forests of NSW (2000). Search on for rare plants and animals, Hunter State forests. Media release, 24 February 2000.

Thompson, J. (1976). A revision of Tetratheca (Tremandraceae), Telopea 1(3), 139-215.

Winning, G. (1992). Conservation status of rare plants in the Lake Macquarie area, unpublished report prepared for Lake Macquarie City Council.

Wyong Shire Council (2003). Draft Wyong Conservation Strategy. Strategic Planning Department, Wyong Shire Council.

Conservation advice

Tetratheca juncea is a low growing, usually leafless shrub with clumps of stems to 1 m or more in length that bear deep lilac-pink or rarely white flowers. Tetratheca juncea occurs largely in coastal and subcoastal areas. It usually grows in low nutrient soils on hills and ridges and along creeks, and is associated with woodland and open forest dominated by various species of Eucalyptus and other tree species, or with heath vegetation. Tetratheca juncea is restricted to the north coast and central coast botanical regions of New South Wales. Most populations occur in the Wyong and Lake Macquarie local government areas, with isolated populations present in the Cessnock, Newcastle, Port Stephens and Great Lakes local government areas (Hawkesbury Nepean and Hunter Central Rivers Natural Resource Management Regions).

Key threats to the species include:

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

* An important population is one that is necessary for a species' long term survival and recovery. This may include populations that are:

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

No Recovery Plan is currently in place for Tetratheca juncea.

Priority for the development of recovery plan: High. The development of a Recovery Plan is considered to be a high priority for this species as it is severely fragmented, has a restricted geographic distribution, and its habitat is subject to ongoing pressure from land development in the Wyong and Lake Macquarie local government areas.