Hibbertia sp. Bankstown (R.T.Miller & C.P.Gibson s.n. 18/10/06) - critically endangered species listing

NSW Scientific Committee - final determination

The Scientific Committee, established by the Threatened Species Conservation Act, has made a Final Determination to list the shrub Hibbertia sp. Bankstown (R.T.Miller & C.P.Gibson s.n. 18/10/06) as a CRITICALLY ENDANGERED SPECIES in Part 1 of Schedule 1A of the Act. Listing of Critically Endangered species is provided for by Part 2 of the Act.

 

The Scientific Committee has found that:

 

1. Hibbertia sp. Bankstown (R.T.Miller & C.P.Gibson s.n. 18/10/06) (family Dilleniaceae) is a prostrate shrub with spreading, hairless, wiry branches up to 40 cm in length. Its leaves are oblong-lanceolate to almost linear, 3–6 mm long by 0.8–1.4 mm wide. The flowers are yellow with notched petals; the floral bracts subtend the calyx; the outer calyx lobes are 5.3-6.3 mm long, scarcely ridged and very shortly hairy to almost hairless outside, hairless inside (H. Toelken in litt. 2007; TSSC 2009a).

 

2. Hibbertia sp. Bankstown (R.T.Miller & C.P.Gibson s.n. 18/10/06) is the preferred phrase name for this species, which has not yet been formally named and described; it also known by the unpublished name ‘Hibbertia glabrescens Toelken MS’ (e.g. Bankstown Airport Ltd 2008), and for a short period after its discovery in 2006 was misidentified as H. puberula Toelken. The closest relatives of Hibbertia sp. Bankstown (R.T.Miller & C.P.Gibson s.n. 18/10/06) are H. puberula and the unpublished ‘H. yerambaensis Toelken MS’, both of which have (H. Toelken in litt. 2007) young branches hairy (sometimes becoming nearly hairless with age); the floral bracts separate from the calyx; the outer calyx lobes 5.8—10.4 mm long and prominently ridged towards the apex, with numerous long hairs outside and fine hairs inside (H. Toelken in litt. 2007).

 

3. Hibbertia sp. Bankstown (R.T.Miller & C.P.Gibson s.n. 18/10/06) is endemic to New South Wales and is currently known to occur in only one population at Bankstown Airport in Sydney’s southern suburbs, in the Bankstown local government area. The species is not known from any conservation reserves. The population comprises fewer than 100 individuals.

 

4. The airport site is very heavily modified from the natural state, now largely lacks canopy species, and is currently a low grass/shrub association with many pasture grasses and other introduced herbaceous weeds. Soil at the site is a sandy (Tertiary) alluvium with a high silt content. The assemblage of locally indigenous species at or near the site, and thought to be remnant, includes (DEWHA 2009) a few canopy species such as Angophora floribunda (Rough-barked Apple), Banksia integrifolia (Coast Banksia), Eucalyptus tereticornis (Forest Red Gum), E. parramattensis (Parramatta Red Gum) and Melaleuca decora, and understorey species including Acacia suaveolens (Sweet Wattle), Aristida warburgii, Caesia parviflora (Pale Grass-Lily), Dianella longifolia, Goodenia hederacea, G. paniculata (Fan Flower), Hibbertia diffusa (Mat Guinea-flower), Kunzea ambigua (White Kunzea), Laxmannia gracilis, Leptospermum polygalifolia, Microtis parviflora (Slender Onion-orchid), Themeda australis (Kangaroo Grass) and Thelymitra pauciflora (Slender Sun-orchid). This assemblage and soil type are consistent with an inferred pre-settlement cover of Castlereagh Ironbark Forest (sensu Benson 1992, Map Unit 9e); Tozer 2003, Map Unit 3) [albeit with some atypical species]; both variants of these map units are components of the broader “Cooks River/Castlereagh Ironbark Forest in the Sydney Basin Bioregion that is listed as an Endangered Ecological Community under the Threatened Species Conservation Act 1995.

 

5. Hibbertia sp. Bankstown (R.T.Miller & C.P.Gibson s.n. 18/10/06) has been observed to flower from October to December, with seed setting from October to January. Most Hibbertia species are primarily pollinated by bees, but many have specialised mechanisms requiring particular bee species (Bernhardt 1984; Horn 2007); beetles and syrphid flies (hoverflies) are also possible pollinators for some species. The degree of pollinator specificity for Hibbertia sp. Bankstown, the availability of pollinators at the site, the level of seed-set, and the breeding system, are all unknown. Seeds of many Hibbertia species are myrmecochorous (ant-dispersed) (Berg 1975; Rice & Westoby 1981; Horn 2007). Whether suitable ant vectors are present at the site is not known. Seed dormancy is known to occur in several Hibbertia species (Schatral et al. 1997; Cochrane 2002; Allan et al. 2004 and references therein), and the species is likely to have a persistent soil seedbank. Many species of Hibbertia are capable of resprouting from the main rootstock after fire and mechanical disturbance (e.g. Benson & McDougall 1995), but other forms of vegetative reproduction (e.g. rhizomes) are not recorded for Hibbertia sensu stricto (Horn 2007).

 

6. Hibbertia sp. Bankstown (R.T.Miller & C.P.Gibson s.n. 18/10/06) has in all likelihood undergone past decline as a result of initial land-clearing and subsequent urbanisation of nearly all the surrounding area. “Historical aerial photography depicts continual modification of habitat and removal of native vegetation from Sydney Basin, the Bankstown LGA, Georges River floodplain and land in and around Bankstown Airport. This modification of habitat has affected individual species and is likely to have affected the occurrence of H. sp. Bankstown (R.T.Miller & C.P.Gibson s.n. 18/10/06, especially as the location of this species is bound by urban development (TSSC 2009[a])” (DEWHA 2009).

 

7. Hibbertia sp. Bankstown (R.T.Miller & C.P.Gibson s.n. 18/10/06) has an extent of occurrence and an area of occupancy of 4 km2 based on occupancy of a single 2 x 2 km grid cell, the scale recommended for assessing area of occupancy by IUCN (2008). The actual area of known patches is less than 1 000 m2.

 

8. The population is subject to land management activities consistent with its position near an airport runway, including periodic reduction of vegetation height. The main proximate threats include impacts associated with airport grounds maintenance and modification; competition and changes to soil and microclimate associated with invasive weeds; and the uncertainty involved in identifying and maintaining an appropriate area management regime, including mowing or slashing, that maintains or favours growth and recruitment of the Hibbertia and helps control competing weeds, including Kikuyu (Pennisetum clandestinum) and African Lovegrass (Eragrostis curvula) (TSSC 2009b). ‘Invasion of native plant communities by exotic perennial grasses’ is listed as a Key Threatening Process under the Threatened Species Conservation Act 1995.

 

9. Other potential threats include effects associated with future development activities on airport lands, possible reduced visitation by suitable pollinators, low seed set, absence of seed germination cues, and stochastic events due to the small population size. A number of Hibbertia species in Western Australia are known to be susceptible to Phytophthora Root Rot disease (Cochrane 2002; DEC WA 2009; Groves et al. undated). The susceptibility of New South Wales species of Hibbertia is poorly known, but a number of eastern Australian members of the genus are known to be susceptible (McDougall 2005). ‘Infection of native plants by Phytophthora cinnamomi’ is listed as a Key Threatening Process under the Threatened Species Conservation Act 1995. ‘Dieback caused by Phytophthora cinnamomi’ is listed as a Key Threatening Process under the Commonwealth Environment Protection and Biodiversity Conservation Act 1999.

 

10. Hibbertia sp. Bankstown (R.T.Miller & C.P.Gibson s.n. 18/10/06) is listed as Critically Endangered under the Commonwealth Environment Protection and Biodiversity Conservation Act 1999 (TSSC 2009a).

 

11. Hibbertia sp. Bankstown (R.T.Miller & C.P.Gibson s.n. 18/10/06) is eligible to be listed as a Critically Endangered species as, in the opinion of the Scientific Committee, it is facing an extremely high risk of extinction in New South Wales in the immediate future as determined in accordance with the following criteria as prescribed by the Threatened Species Conservation Regulation 2002:

 

Clause 15

The geographic distribution of the species is estimated or inferred to be:

(a) very highly restricted,

and:

(d) a projected or continuing decline is observed, estimated or inferred in either:

(i) an index of abundance appropriate to the taxon, or

(ii) geographic distribution, habitat quality or diversity, or genetic diversity.

 

Clause 16

The estimated total number of mature individuals of the species is:

(a) very low,

and:

(d) a projected or continuing decline is observed, estimated or inferred in either:

(i) an index of abundance appropriate to the taxon, or

(ii)geographic distribution, habitat quality or diversity, or genetic diversity.

 

 

Dr Richard Major

Chairperson

Scientific Committee

 

Proposed Gazettal date: 23/04/10

Exhibition period: 23/04/10 - 18/06/10

 

References

 

Allan SM, Adkins SW, Preston CA, Bellairs SM (2004) Improved germination of the Australian natives: Hibbertia commutata, Hibbertia amplexicaulis (Dilleniaceae), Chamaescilla corymbosa (Liliaceae) and Leucopogon nutans (Epacridaceae). Australian Journal of Botany 52, 345-351

 

Bankstown Airport Ltd (2008) Sydney Metropolitan Airports Environment Management System Issue No 1, 01/09/08 Action Plan 1 – Vegetation Management – sensitive areas (unpublished).

 

Benson DH (1992) The natural vegetation of the Penrith 1:100 000 map sheet. Cunninghamia 2, 541-596.

 

Benson D, McDougall L (1995) Ecology of Sydney plant species Part 3: Dicotyledon families Cabombaceae to Eupomatiaceae. Cunninghamia 4, 217-431.

 

Berg RY (1975) Myrmecochorous plants in Australia and their dispersal by ants. Australian Journal of Botany 23, 475-508.

 

Bernhardt P (1984) The pollination biology of Hibbertia stricta (Dilleniaceae). Plant Systematics and Evolution 147, 267-277.

 

Cochrane A [2002] Hibbertia. Seed notes for Western Australia no 17. Perth Branch of the Wildflower Society of Western Australia Inc.

 

DEC WA (2009) Common Indicator Species for the Presence of Disease caused by Phytophthora cinnamomi. Department of Environment and Conservation, Western Australia. www.dec.wa.gov.au/pdf/projects/dieback/dieback_indicators.pdf (accessed 19 June 2009)

 

DEWHA (2009) Hibbertia sp. Bankstown (R.T.Miller & C.P.Gibson s.n. 18/10/06) in Species Profile and Threats Database, Department of the Environment, Water, Heritage and the Arts, Canberra. (www.environment.gov.au/cgi-bin/sprat/public/publicspecies.pl?taxon_id=81969, accessed 19 June 2009)

 

Groves E, Hardy G, McComb J [undated] Western Australian Natives Susceptible to Phytophthora cinnamomi. (www.cpsm.murdoch.edu.au/downloads/resources/natives_susceptible.pdf, accessed 22 June 2009)

 

Horn JW (2007) Dilleniaceae. In ‘The families and genera of flowering plants. Vol. IX Flowering Plants – Eudicots Berberidopsidales [to] Sabiaceae’. (Ed. K. Kubitzki) pp. 132-154. (Springer: Berlin)

 

IUCN (2008) ‘Guidelines for using the IUCN Red List Categories and Criteria. Version 7.0.’ (Standards and Petitions Working Group of the IUCN Species Survival Commission Biodiversity Assessments Sub-committee: Switzerland). (http://intranet.iucn.org/webfiles/doc/SSC/RedList/RedListGuidelines.pdf).

 

McDougall, K (2005) Appendix 4 - The responses of native Australian plant species to Phytophthora cinnamomi. In: O’Gara E, Howard K, Wilson B and Hardy GEStJ (2005) Management of Phytophthora cinnamomi for Biodiversity Conservation in Australia: Part 2 - National Best Practice Guidelines. A report funded by the Commonwealth Government Department of the Environment and Heritage by the Centre for Phytophthora Science and Management, Murdoch University, Western Australia. (http://www.environment.gov.au/biodiversity/invasive/publications/p-cinnamomi.html, accessed 22 June 2009).

 

Rice B, Westoby M (1981) Myrmecochory in sclerophyll vegetation of the West Head, New South Wales. Australian Journal of Ecology 6, 291-298.

 

Schatral A, Osborne JM, Fox JED (1997) Dormancy in seeds of Hibbertia cuneiformis and H. huegelii (Dilleniaceae). Australian Journal of Botany 45, 1045-1053.

 

Tozer M (2003) The natural vegetation of the Cumberland Plain, western Sydney: systematic classification and field identification of communities. Cunninghamia 8, 1-75.

 

TSSC (2009a). Commonwealth Listing Advice on Hibbertia sp. Bankstown (R.T. Miller & C.P.Gibson s.n. 18/10/06). Threatened Species Scientific Committee; Department of the Environment, Water, Heritage and the Arts. (http://www.environment.gov.au/biodiversity/threatened/species/pubs/81969-listing-advice.pdf, accessed 18 June 2009)

 

TSSC (2009b). Commonwealth Conservation Advice on Hibbertia sp. Bankstown (R.T. Miller & C.P.Gibson s.n. 18/10/06). Threatened Species Scientific Committee; Department of the Environment, Water, Heritage and the Arts. (www.environment.gov.au/biodiversity/threatened/species/pubs/81969-conservation-advice.pdf, accessed 18 June 2009)

Page last updated: 28 February 2011