Biodiversity

Species Profile and Threats Database


For information to assist proponents in referral, environmental assessments and compliance issues, refer to the Policy Statements and Guidelines (where available), the Conservation Advice (where available) or the Listing Advice (where available).
 
In addition, proponents and land managers should refer to the Recovery Plan (where available) or the Conservation Advice (where available) for recovery, mitigation and conservation information.

EPBC Act Listing Status Listed as Endangered as Prostanthera junonis
Recovery Plan Decision Recovery Plan required, this species had a recovery plan in force at the time the legislation provided for the Minister to decide whether or not to have a recovery plan (19/2/2007).
 
Adopted/Made Recovery Plans Somersby Mintbush Prostanthera junonis Recovery Plan - 2000-2005 (NSW National Parks & Wildlife Service, 2000m) [Recovery Plan] as Prostanthera junonis.
 
Federal Register of
    Legislative Instruments
Declaration under s178, s181, and s183 of the Environment Protection and Biodiversity Conservation Act 1999 - List of threatened species, List of threatened ecological communities and List of threatening processes (Commonwealth of Australia, 2000) [Legislative Instrument] as Prostanthera junonis.
 
State Government
    Documents and Websites
NSW:Review of the Threatened Species Conservation Act Flora Schedules: Recommendations to the Scientific Committee: Final Summary Report December 2002 (Hogbin, P., 2002) [Report].
NSW:Somersby Mint-bush - profile (NSW Department of Environment, Climate Change and Water (NSW DECCW), 2005kc) [Internet].
NSW:Prostanthera junonis Threatened Species Information (NSW National Parks and Wildlife Service (NSW NPWS), 2000ao) [Information Sheet].
NSW:Environmental Impact Assessment Guidelines - Prostanthera junonis (NSW National Parks and Wildlife Service (NSW NPWS), 2000ap) [Internet].
State Listing Status
NSW: Listed as Endangered (Threatened Species Conservation Act 1995 (New South Wales): December 2013 list) as Prostanthera junonis
Scientific name Prostanthera junonis [64960]
Family Lamiaceae:Lamiales:Magnoliopsida:Magnoliophyta:Plantae
Species author B.J.Conn
Infraspecies author  
Reference Telopea 7(3) (1997) 237, fig. 3
Other names Prostanthera sp. Somersbey (B.J.Conn 4024) [64534]
Distribution map Species Distribution Map

This is an indicative distribution map of the present distribution of the species based on best available knowledge. See map caveat for more information.

Illustrations Google Images

Scientific name: Prostanthera junonis.

Common name: Somersby Mintbush

The Somersby Mintbush is a low, decumbent (branches growing along the ground, with tips growing upwards), sub-shrub, which grows 0.1—0.3 m high. The species is often stoloniferous (stems form roots at the nodes, which grow into the ground). Flowers are very pale mauve to almost white (Conn 1997; Miller 1999).

The Somersby Mintbush is currently known only from the eastern parts of the Somersby Plateau in the Gosford local government area in NSW (Conn 1997). The species is known to occur at nine locations within a total extent of 19 km. The species previously occurred over a broader range, and is known to have become locally extinct in some areas (Quinn et al. 1995).

The species total area of occupancy is currently 41.75 ha. The total number of individuals was previously estimated to be greater than 3200 (NSW National Parks & Wildlife Service 2000m), but the current population abundance is not known.

The Somersby Mintbush occurs in nine distinct populations, which are listed below (NSW National Parks & Wildlife Service 2000m):

Site No Site Name Population size Tenure
1 Wiseman's Ferry Road 30 Gosford City Council
2 Raverson Close 80—100 Private Land
3A Reeves Road 4 Crown Reserve for Recreation & Preservation of Flora & Fauna
3B Reeves Road 31 Crown Reserve for Recreation & Preservation of Flora & Fauna
4 Gindurra Road 295 Private Land
5 Barnes Road 63 Private Land
6 Mangrove Tower 72 Private Land
7A Resevoir Road 4 Private Land
7B* Resevoir Road 277 National Park
7C* Resevoir Road 2409 National Park
8A* Silvesters Road 10 Water Catchment Area: Gosford City Council
8B* Silvesters Road 20 Private Land
8C* Silvesters Road 25 Private Land
9* Konda Road 191 National Park

The Somersby Mintbush frequently occurs along drainage lines or in seepage areas, usually in shallow, coarse, gravelly, white-grey, sandy soils overlying Hawkesbury Sandstone. This substrate supports an open-woodland community dominated by tree species such as Corymbia gummifera, Angophora costata, A. hispidula, Eucalyptus haemastoma, E. piperita, E. punctata and E. sieberi. The understory is dominated by a dense cover of rush and sedge species, including Empodisma minus and Lepyrodia scariosa, and shrub species, including Acacia oxycedrus, A. suaveolens, Banksia ericifolia, B. serrata, Bauera rubioides var. microphylla, Darwinia fasicularis, Dillwynia floribunda, Epacris obtusifolia, Grevillea buxifolia, G. sericea, G. speciosa, Hakea sericea, H. teretifolia, Hemigenia purpurea, Kunzea capitata, Leptospermum polygalifolium, Persoonia isophylla, P. levis, Petrophile pulchella, Pimelea linifolia, Sprengelia incarnata and Thelionema umbellata (Conn 1997).

Although the Somersby Mintbush is a colonising species, the habitat of all populations has been severely disturbed by anthropogenic pressures. The vegetation at some sites have been extensively cleared for urban development. More importantly, however, there has been extensive removal and/or partial relocation of soil at some sites (Conn 1997).

The Somersby Mintbush flowers from July to October, with fruiting from October to December (Conn 1997). The seeds of the Somersby Mintbush germinate in response to light and smoke and it is likely that recruitment is linked to the occurrence of fire. The occurrence of populations of the species adjacent to fire trails suggests that favourable light conditions as a result of reduced vegetative competition may also promote recruitment (NSW National Parks & Wildlife Service 2000m).

The breeding cycle of the species is poorly known. Preliminary study of the species' reproductive biology by Tierney (1996) indicate it is capable of surviving by utilising both cross-pollination and self-pollination methods of fertilisation. It was found that higher seedset and viability result from cross-pollination, however, seeds produced from self-pollination are also viable. The species was also observed to reproduce vegetatively by stolons. Thus, self-pollination and clonal growth may be a response of the species in circumstances of severe disturbance, to ensure continued production of offspring (NSW National Parks & Wildlife Service 2000m).

The Somersby Mintbush is frequently confused with the Narrow-leaved Hemigenia (Hemigenia purpurea), as the Narrow-leaved Hemigenia is a common species which occupies the same habitat.

H. purpurea is a small shrub 0.1—0.2 m high, with mauve flowers, similar in shape and size to the Somersby Mintbush. The two species can be easily distinguished using the following characteristics: H. purpurea has a calyx (collection of sepals) with five long teeth-shaped sepals as opposed to two lip-shaped sepals in P. junonis and H. purpurea has linear leaves, in whorls of three occurring densely along the branches, whereas P. junonis has elliptic to narrowly elliptic leaves, opposite and widely spaced along the branches (NSW National Parks & Wildlife Service 2000m).

There are a range of threats to the Somersby Mintbush across the species’ range. Many populations face similar threats, particularly access-related habitat degradation, weed invasion and inappropriate fire regimes (NSW National Parks & Wildlife Service 2000m). Some further detail on individual threats can be found below.

Access-related habitat degradation

Several of the sites where the species occurs have extensive tracks which enable access of people to populations. Uncontrolled site access has led to the degradation of several of the sites through vegetation trampling, track widening and rubbish dumping. In addition, the Great North Walk passes through and near populations of P. junonis (NSW National Parks & Wildlife Service 2000m).

Weed invasion

According to the NSW National Parks and Wildlife Service, weed invasion has been apparent at several of the sites, however, recent data is not available and the current state of weed invasion is not known. Some of the sub-populations at site 7 occur directly downslope of a poultry farm and were reported to suffer from invasion of Senecio madagascarensis and Andropogon virginicus. A large area of weed infestation was also known to occur within 10 m of the Gindurra Rd population. The Raverson Close population was severely degraded due to the introduction of exotic grasses for soil stabilisation. The concern regarding weed invasion is that invading weeds can displace native plants at a site and restrict seed germination, which will eventually change the vegetation structure of the habitat (NSW National Parks & Wildlife Service 2000m).

Inappropriate fire regimes

Given the frequent occurrence of the Somersby Mintbush along access tracks and boundaries, there is a high potential for it to be disturbed or destroyed by fire control activities. Populations 7 and 8 have already had fire control lines placed in their immediate vicinity. Fuel reduction involving bulldozing of areas adjacent to property boundaries or the construction of control lines during emergency situations may lead to degradation of populations. Fuel reduction activities may involve frequent fuel reduction burns; the impact of which is unknown (NSW National Parks & Wildlife Service 2000m).

Habitat clearing for development

At least five of the nine populations have been either directly or indirectly affected by development. Although, it is unknown as to whether development has resulted in the complete removal of any of these populations, the culmulative impacts of development and long-term, indirect impacts of habitat loss, fragmentation and degradation remain serious concerns for this species (NSW National Parks & Wildlife Service 2000m).

Documents relevant to the management of the Somersby Mintbush can be found at the start of the profile.

The following table lists known and perceived threats to this species. Threats are based on the International Union for Conservation of Nature and Natural Resources (IUCN) threat classification version 1.1.

Threat Class Threatening Species References
Agriculture and Aquaculture:Agriculture and Aquaculture:Fertiliser application Species threats data recorded on the SPRAT database between 1999-2002 (Department of Sustainability, Environment, Water, Population and Communities (DSEWPaC), 2012i) [Database].
Climate Change and Severe Weather:Habitat Shifting and Alteration:Habitat modification with associated erosion Four rare and/or threatened new species of Prostanthera Section Prostanthera (Labiatae) from New South Wales. Telopea. 7(3):231-244. (Conn, B.J., 1997) [Journal].
Ecosystem/Community Stresses:Ecosystem Degradation:Decline in habitat quality Somersby Mintbush Prostanthera junonis Recovery Plan - 2000-2005 (NSW National Parks & Wildlife Service, 2000m) [Recovery Plan].
Ecosystem/Community Stresses:Indirect Ecosystem Effects:Restricted geographical distribution (area of occupancy and extent of occurrence) Somersby Mintbush Prostanthera junonis Recovery Plan - 2000-2005 (NSW National Parks & Wildlife Service, 2000m) [Recovery Plan].
Energy Production and Mining:Mining and Quarrying:Habitat modification through open cut mining/quarrying activities Somersby Mintbush Prostanthera junonis Recovery Plan - 2000-2005 (NSW National Parks & Wildlife Service, 2000m) [Recovery Plan].
Human Intrusions and Disturbance:Recreational Activities:Disturbance, especially from human recreational activities and development Somersby Mintbush Prostanthera junonis Recovery Plan - 2000-2005 (NSW National Parks & Wildlife Service, 2000m) [Recovery Plan].
Human Intrusions and Disturbance:Recreational Activities:Habitat degradation associated with recreational activities such as horse riding Prostanthera junonis in Species Profile and Threats (SPRAT) database (Department of the Environment and Heritage (DEH), 2006so) [Internet].
Human Intrusions and Disturbance:Recreational Activities:Habitat disturbance from recreational vehicle use Prostanthera junonis in Species Profile and Threats (SPRAT) database (Department of the Environment and Heritage (DEH), 2006so) [Internet].
Invasive and Other Problematic Species and Genes:Invasive Non-Native/Alien Species:Competition and/or habitat degradation by weeds Somersby Mintbush Prostanthera junonis Recovery Plan - 2000-2005 (NSW National Parks & Wildlife Service, 2000m) [Recovery Plan].
Invasive and Other Problematic Species and Genes:Invasive Non-Native/Alien Species:Infection by parasites Somersby Mintbush Prostanthera junonis Recovery Plan - 2000-2005 (NSW National Parks & Wildlife Service, 2000m) [Recovery Plan].
Invasive and Other Problematic Species and Genes:Invasive Non-Native/Alien Species:Vegetation and habitat loss caused by dieback Phytophthora cinnamomi Threat abatement plan for disease in natural ecosystems caused by Phytophthora cinnamomi (Department of the Environment, Water, Heritage and the Arts (DEWHA), 2009w) [Threat Abatement Plan].
Somersby Mintbush Prostanthera junonis Recovery Plan - 2000-2005 (NSW National Parks & Wildlife Service, 2000m) [Recovery Plan].
Invasive and Other Problematic Species and Genes:Invasive and Other Problematic Species and Genes:Presence of pathogens and resulting disease Somersby Mintbush Prostanthera junonis Recovery Plan - 2000-2005 (NSW National Parks & Wildlife Service, 2000m) [Recovery Plan].
Invasive and Other Problematic Species and Genes:Problematic Native Species:Competition, grazing, predation and/or habitat degradation by rats Four rare and/or threatened new species of Prostanthera Section Prostanthera (Labiatae) from New South Wales. Telopea. 7(3):231-244. (Conn, B.J., 1997) [Journal].
Natural System Modifications:Dams and Water Management/Use:Changes in hydrology including habitat drainage Four rare and/or threatened new species of Prostanthera Section Prostanthera (Labiatae) from New South Wales. Telopea. 7(3):231-244. (Conn, B.J., 1997) [Journal].
Report on rare and threatened plants of north-eastern New South Wales (Quinn, F., J.B. Williams, C.L. Gross & J. Bruhl, 1995) [Report].
Natural System Modifications:Fire and Fire Suppression:Inappropriate and/or changed fire regimes (frequency, timing, intensity) Somersby Mintbush Prostanthera junonis Recovery Plan - 2000-2005 (NSW National Parks & Wildlife Service, 2000m) [Recovery Plan].
Natural System Modifications:Fire and Fire Suppression:Inappropriate prescribed regimes and/or vegetation management to control fire regimes Somersby Mintbush Prostanthera junonis Recovery Plan - 2000-2005 (NSW National Parks & Wildlife Service, 2000m) [Recovery Plan].
Pollution:Garbage and Solid Waste:Dumping of household and industrial waste Somersby Mintbush Prostanthera junonis Recovery Plan - 2000-2005 (NSW National Parks & Wildlife Service, 2000m) [Recovery Plan].
Residential and Commercial Development:Housing and Urban Areas:Habitat loss, modification and fragmentation due to urban development Four rare and/or threatened new species of Prostanthera Section Prostanthera (Labiatae) from New South Wales. Telopea. 7(3):231-244. (Conn, B.J., 1997) [Journal].
Somersby Mintbush Prostanthera junonis Recovery Plan - 2000-2005 (NSW National Parks & Wildlife Service, 2000m) [Recovery Plan].
Residential and Commercial Development:Residential and Commercial Development:Habitat modification (clearance and degradation) due to urban development Somersby Mintbush Prostanthera junonis Recovery Plan - 2000-2005 (NSW National Parks & Wildlife Service, 2000m) [Recovery Plan].

Conn, B.J. (1997). Four rare and/or threatened new species of Prostanthera Section Prostanthera (Labiatae) from New South Wales. Telopea. 7(3):231-244.

Miller, R. (1999). A Review of Unnamed Species of Prostanthera Described in Flora of New South Wales vol. III and Telopea 7(3). Lasianthos: The Labiates of Australia. 2:4-13. SGAP Prostanthera & Westringia Study Group.

NSW National Parks & Wildlife Service (1998). Prostanthera junonis Draft Recovery Plan. Hurstville: NSW NPWS.

NSW National Parks & Wildlife Service (2000m). Somersby Mintbush Prostanthera junonis Recovery Plan - 2000-2005. [Online]. Hurstville: NSW NPWS. Available from: http://www.environment.gov.au/biodiversity/threatened/publications/recovery/p-junonis/index.html.

Quinn, F., J.B. Williams, C.L. Gross & J. Bruhl (1995). Report on rare and threatened plants of north-eastern New South Wales. Armidale: University of New England.

Tierney, D.A. (1996). Prostanthera sp. 'Somersby'; is recovery possible?. M.Sc. Thesis.

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This database is designed to provide statutory, biological and ecological information on species and ecological communities, migratory species, marine species, and species and species products subject to international trade and commercial use protected under the Environment Protection and Biodiversity Conservation Act 1999 (the EPBC Act). It has been compiled from a range of sources including listing advice, recovery plans, published literature and individual experts. While reasonable efforts have been made to ensure the accuracy of the information, no guarantee is given, nor responsibility taken, by the Commonwealth for its accuracy, currency or completeness. The Commonwealth does not accept any responsibility for any loss or damage that may be occasioned directly or indirectly through the use of, or reliance on, the information contained in this database. The information contained in this database does not necessarily represent the views of the Commonwealth. This database is not intended to be a complete source of information on the matters it deals with. Individuals and organisations should consider all the available information, including that available from other sources, in deciding whether there is a need to make a referral or apply for a permit or exemption under the EPBC Act.

Citation: Department of the Environment (2014). Prostanthera junonis in Species Profile and Threats Database, Department of the Environment, Canberra. Available from: http://www.environment.gov.au/sprat. Accessed Fri, 22 Aug 2014 19:12:27 +1000.