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 Vulnerable as Boronia gunnii
Listing and Conservation Advices Commonwealth Listing Advice on Gunn's Boronia (Boronia gunnii) (Threatened Species Scientific Committee, 2005ac) [Listing Advice].
 
Commonwealth Conservation Advice on Boronia gunnii (Threatened Species Scientific Committee, 2008zl) [Conservation Advice].
 
Recovery Plan Decision Recovery Plan not required, included on the Not Commenced List (1/11/2009).
 
Adopted/Made Recovery Plans
Federal Register of
    Legislative Instruments
Inclusion of species in the list of threatened species under section 178 of the Environment Protection and Biodiversity Conservation Act 1999 (31/03/05) (Commonwealth of Australia, 2005i) [Legislative Instrument] as Boronia gunnii.
 
State Government
    Documents and Websites
TAS:Threatened Species Notesheet-Boronia gunnii (Tasmanian Department of Primary Industries, Parks, Water and Environment (Tas. DPIPWE), 2008b) [Information Sheet].
TAS:Boronia gunnii (Gunn's Boronia, Cataract Gorge Boronia): Species Management Profile for Tasmania's Threatened Species Link (Threatened Species Section (TSS), 2014fu) [State Action Plan].
State Listing Status
TAS: Listed as Vulnerable (Threatened Species Protection Act 1995 (Tasmania): September 2012 list) as Boronia gunnii
Scientific name Boronia gunnii [29394]
Family Rutaceae:Sapindales:Magnoliopsida:Magnoliophyta:Plantae
Species author J.D.Hook.
Infraspecies author  
Reference Flora Tasmaniae 1: 68, t. 10 (24 Oct. 1855).
Other names Boronia tetrandra var. grandiflora [29939]
Boronia pinnata var. gunnii [60948]
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

Gunn's Boronia is conventionally accepted as a species (CHAH 2014). Boronia gunnii was described by Hooker (1855) and was maintained as a species by Curtis (1956), but subsequently subsumed into Boronia pilosa by Curtis and Morris (1975). Duretto (2003) argued for distinction between the two species and separated Boronia gunnii (Schahinger 2004a).

Gunn's Boronia is an erect, woody shrub growing to 1.2 m tall. Leaves are composed of 5-9 parts, 12-32 mm long, 16-50 mm wide and slightly covered in glandular bristles. Flowers are located in the leaf axils and cluster in groups of 1-7. Sepals are small, triangular and green and petals are pink or white and 5-8 mm long. Fruits are hairless (Threatened Species Scientific Committee 2008zl).

Gunn's Boronia is known to occur primarily in the region surrounding the Aspley River, St Paul’s River and Dukes River, in east Tasmania (Threatened Species Scientific Committee 2008zl). However, the species may occur throughout the Eastern Tiers region and south, almost to Dodges Ferry.

The known range of Gunn's Boronia has substantially reduced since the 1960’s and the species' extent of occurrence and area of occupancy were estimated by Schahinger (2004a) to be 25 km2 and 3-5 ha respectively.

Schahinger conducted extensive surveys for several of the Boronia species, including Boronia gunnii, in 2003 (Schahinger 2004a). The surveys were carried out during the period of August to December and included a number of areas considered unlikely to support the target species. The surveys confirmed the presence of Gunn's Boronia along the lower reaches of the Aspley River, within Douglas-Aspley National Park and along the upper St Pauls River and its tributary, the Dukes River. Surveys of the Denison Rivulet and the lower South Esk River failed to identify any plants (Schahinger 2004a).

The total number of mature individuals of Gunn's Boronia is estimated to be low; approximately 750-900. The species is currently restricted to two populations within an eight kilometre stretch of river habitat in Tasmania's Eastern Tiers region (TSSC 2005ac).

The two currently known populations of Gunn's Boronia occur at St Paul's and Dukes Rivers (approximately 500-600 plants along a 5 km stretch of river) and at Apsley River (approximately 250-300 plants along a 3 km stretch of river).

A third population that was previously known from the lower South Esk River, however, surveys have failed to locate this population and it is now considered to be extinct (Schahinger 2004a;TSSC 2005ac).

During the 1960’s, Gunn's Boronia was known as the Cataract Gorge Boronia, as the population of the Cataract Gorge along the South Esk River was the only one known at the time. In addition to the impacts caused by the earlier construction of the Duck River power station, the construction of the Trevallyn Dam in the 1950’s altered the hydrology of the lower South Esk River. The Reedy Basin site, Cataract Gorge, was flooded and the species habitat downstream at 2nd Basin was invaded by exotic weeds, such as Gorse (Ulex europaeus) and Willow (Salix spp.). Surveys have since failed to locate the species at these locations and the South Esk River population is now considered to be extinct. The loss of Gunn's Boronia from the lower South Esk River has meant a reduction in the species' range from 102 km to 17 km (TSSC 2005ac).

Although Gunn's Boronia is suspected to have undergone a reduction in numbers, there is insufficient data to quantify the degree of decline and insufficient evidence to indicate that the species is likely to undergo a further reduction in numbers in the immediate future (Duretto 2004a).

Gunn's Boronia populations are likely to be subject to some fluctuation in numbers as a result of natural events such as drought and flood (Schahinger 2004a). Upstream hydrological changes have the potential to accentuate these fluctuations if natural flows are further reduced (Schahinger 2004a).

Approximately two thirds of the mature individuals of Gunn's Boronia occur in Mt Puzzler Forest Reserve and Douglas-Apsley National Park, Tasmania. The remaining third occurs within an informal streamside reserve on state forest land (Duretto 2003).

Gunn's Boronia is considered to be strictly associated with riparian areas, occurring in the flood zone of rivers in rock crevices or in the shelter of boulders (Duretto 2004). The species occurs within the altitudes of 125-500 metres above sea level (Schahinger 2004a).

Associated shrubby species include Box Micranthum (Micranthum hexandrum), Small-fruit Hakea (Hakea macrocarpa), Narrow-leaved Wattle (Acacia mucronata), Dusty Miller (Spyridium obovatum), Woolly Tea-tree (Leptospermum lanigerum) and South Esk Heath (Epacris exserta). Gunn's Boronia is known only to occur on the base substrate known as Jurassic dolerite (Duretto 2004).

Gunn's Boronia flowers between October and January and immature fruits have been collected in January (Duretto 2003).

The Gunn’s Boronia differs from other Tasmanian Boronia species by its long, narrowly obovate (egg-shaped) leaves, small, stiff, bristly hairs and glandular, wart-like projections on the stems, shiny glandular areas that dot the leaves and stems and small sepals (Duretto 2003). The specimens of Gunn’s Boronia occurring in eastern Tasmania have longer (to 25 mm long) and narrower (0.75—1.5 mm wide) leaflets than those occurring near Launceston. The styles on the Aspley River specimen have sparse soft hairs, while those from the Launceston area are without hairs (Duretto 2003).

Key threats to Gunn's Boronia include the plant pathogen Phytophthora cinnamomi (dieback), inappropriate fire regimes, permanent flooding of its habitat, increasing runoff and sediment loads from upstream activities and invasion of habitat by exotic weed species (Schahinger 2004a).

The susceptibility of Gunn's Boronia to the soil-borne plant pathogen Phytophthora cinnamomi has not been confirmed; however, the susceptibility of other Boronia species to Phytophthora cinnamomi has long been recognised. Fire can create conditions conducive to an increased abundance and spread of Phytophthora cinnamomi as it reduces organic matter in the soil and associated soil micro-flora/fauna that usually suppress the pathogen. The movement of fire fighters and associated machinery may be a secondary mechanism aiding the spread of Phytophthora cinnamomi (Duretto 2004).

Germination of seeds is improved by fire, although too frequent fire is considered to be detrimental to the survival of the species, prolonged periods between fire events could also threaten the species. It is not known how long seeds remain viable in the soil (Duretto 2003).

Upstream activities that increase runoff and sediment loads, permanent flooding and invasion from exotic weeds have a potential impact on the species' habitat (river banks) (Duretto 2004). The impacts of hydrological changes and weed invasion threats have not yet been quantified for the species.

The Commonwealth Conservation Advice for the Gunn's Boronia identifies a number of priority actions for the recovery of the species (TSSC 2008zl).

Some of the key priority actions are to:

  • identify populations of high conservation value
  • investigate formal conservation agreements, such as the use of conservation agreements, covenants or inclusion in reserve tenure
  • manage any disruptions to water flows
  • develop and implement a suitable fire management strategy for Gunn's Boronia
  • identify appropriate fire intensity and interval to promote seed germination
  • monitor for evidence of outbreaks of Phytophthora cinnamomi
  • identify and remove weeds in Gunn's Boronia habitat
  • undertake seed collection and storage
  • investigate options for linking, enhancing or establishing additional populations. 

Documents relevant to the management of the Gunn's Boronia 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
Ecosystem/Community Stresses:Indirect Ecosystem Effects:Restricted geographical distribution (area of occupancy and extent of occurrence) Commonwealth Listing Advice on Gunn's Boronia (Boronia gunnii) (Threatened Species Scientific Committee, 2005ac) [Listing Advice].
Invasive and Other Problematic Species and Genes:Invasive Non-Native/Alien Species:Competition and/or habitat degradation by weeds Commonwealth Listing Advice on Gunn's Boronia (Boronia gunnii) (Threatened Species Scientific Committee, 2005ac) [Listing Advice].
Invasive and Other Problematic Species and Genes:Invasive Non-Native/Alien Species:Vegetation and habitat loss caused by dieback Phytophthora cinnamomi Commonwealth Conservation Advice on Boronia gunnii (Threatened Species Scientific Committee, 2008zl) [Conservation Advice].
Natural System Modifications:Dams and Water Management/Use:Alteration of hydrological regimes including flooding Commonwealth Listing Advice on Gunn's Boronia (Boronia gunnii) (Threatened Species Scientific Committee, 2005ac) [Listing Advice].
Natural System Modifications:Fire and Fire Suppression:Inappropriate and/or changed fire regimes (frequency, timing, intensity) Commonwealth Listing Advice on Gunn's Boronia (Boronia gunnii) (Threatened Species Scientific Committee, 2005ac) [Listing Advice].
Pollution:Pollution:Changes to water and sediment flows leading to erosion, siltation and pollution Commonwealth Conservation Advice on Boronia gunnii (Threatened Species Scientific Committee, 2008zl) [Conservation Advice].
Species Stresses:Indirect Species Effects:Low numbers of individuals Commonwealth Listing Advice on Gunn's Boronia (Boronia gunnii) (Threatened Species Scientific Committee, 2005ac) [Listing Advice].

Council of Heads of Australasian Herbaria (CHAH) (2014). Australian Plant Census. [Online]. Australian National Herbarium, Australian National Botanic Gardens and Australian Biological Resources Study . Available from: http://www.chah.gov.au/chah/apc/index.html.

Curtis, W.M. (1956). The Student's Flora of Tasmania Part 1. Government Printer, Hobart.

Curtis, W.M. & D.I. Morris (1975). The Student's Flora of Tasmania. Part 1 (Second Edition). Hobart: Government Printer.

Duretto, M. (2004). Letter to Scientific Advisory Committee (Threatened Species), Nature Conservation Branch, DPIWE, 20 September 2004.

Duretto, M.F. (2003). Notes on Boronia (Rutaceae) in eastern and northern Australia. Lebel, T. & M. Duretto, eds. Muelleria. 17:19-135. Melbourne: Royal Botanic Gardens.

Hooker, J.D. (1855). The Botany of the Antarctic Voyage of H.M. Discovery Ships Erebus and Terror in the Years 1839-1843 III. In: Flora Tasmaniae. 1. Lovell reeve, London.

Schahinger, R. (2004a). Distribution and Conservation Status of the Tasmanian Endemic Shrubs Boronia gunnii, Boronia hemichiton and Boronia hippopala. Report to the Threatened Species Unit, Department of Primary Industries, Water and Environment, Hobart, Tasmania.

Threatened Species Scientific Committee (2005ac). Commonwealth Listing Advice on Gunn's Boronia (Boronia gunnii). [Online]. Available from: http://www.environment.gov.au/biodiversity/threatened/species/boronia-gunnii.html.

Threatened Species Scientific Committee (2008zl). Commonwealth Conservation Advice on Boronia gunnii. [Online]. Department of the Environment, Water, Heritage and the Arts. Available from: http://www.environment.gov.au/biodiversity/threatened/species/pubs/29394-conservation-advice.pdf.

EPBC Act email updates can be received via the Communities for Communities newsletter and the EPBC Act newsletter.

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). Boronia gunnii in Species Profile and Threats Database, Department of the Environment, Canberra. Available from: http://www.environment.gov.au/sprat. Accessed Thu, 2 Oct 2014 09:17:24 +1000.