Banksia conferta A.S.George subsp. conferta - critically endangered species listing

The Scientific Committee, established by the Threatened Species Conservation Act, has made a Final Determination to list the shrub Banksia conferta A.S.George subsp. conferta as a CRITICALLY ENDANGERED SPECIES on Part 1 of Schedule 1A of the Act. Listing of critically endangered species is provided for by Part 2 of the Act.

NSW Scientific Committee - final determination

The Scientific Committee has found that:

1. Banksia conferta A.S.George subsp.  conferta (family Proteaceae) is an endemic Australian shrub that has been described by George (1981) as follows:

"A shrub to 4 m, rather irregular. Bark roughly tessellated, grey. Branchlets villous becoming glabrous, orange, red or brown. Leaves whorled, elliptic to obovate, 3.5-12 cm long, 0.7-4 cm wide, entire, somewhat undulate, hirsute and pubescent above becoming glabrous, hirsute below, becoming glabrous on the nerves but otherwise white-tomentose. Inflorescence cylindrical, 7-19 cm long, 5-6 cm wide at flowering. Flowers yellowish-green to pinkish-brown in bud, golden when open; styles pale yellow. Perianth 20-25 mm long, including limb of 3-4 mm, closely pubescent outside, glabrous inside. Pistil 22-26 mm long, slender, glabrous; pollen presenter less than 1 mm long, scarcely thickened. Old flowers persistent for several years. Follicles many, narrowly elliptic, 8-15 mm long, 2-6 mm high, 3-5 mm wide; valves semi-elliptic, smooth, hirsute becoming glabrous where exposed; mostly remaining closed until burnt. Seed obovate, 14-17 mm long; seed body lunate, 8-9 mm long, 2-3.5 mm wide, smooth; wing 6-7mm wide."

2. In NSW, Banksia conferta subsp.  conferta is currently known from a single population occupying c. 14 ha, a very highly restricted geographic range, in the Coorabakh National Park, north west of Lansdowne. The population here comprises a low number of mature individuals (approximately 500-1000 plants at varying stages of development) with c. 10% of individuals occurring along a roadside (I. Turner, pers. comm.).

3. Banksia  conferta subsp.  conferta is found on exposed rocky slopes in well-drained skeletal soil derived from high-quartz conglomerate. It occurs in comparatively low open forest with a dry sclerophyll understorey (Griffith 2005).

4. Banksia conferta subsp.  conferta is also known from the Lamington Plateau and the Glass House Mountains in Queensland, more than 400 km to the north of Lansdowne, where it occurs on steep rocky slopes of granite and sandstone in scrub (George 1999).

5. The standing plants of Banksia conferta subsp.  conferta are single-stemmed and likely to be killed by fire, while its seeds are held within serotinous woody cones, and are released after fire (George 1999). Plant species with these life-history characteristics are entirely dependent on canopy-stored seed for persistence after fires, and their populations are susceptible to declines or extinctions when fires recur at very short or very long intervals (Keith 1996). The death of standing plants in a fire and reliance on a canopy seed bank for regeneration may result in no overlap between successive generations of plants at a site. Extreme fluctuations in population size may thus be inferred to occur depending on the time between fires and establishment success of seedlings (Griffith 2005). 'High frequency fire resulting in the disruption of life cycle processes in plants and animals and loss of vegetation structure and composition' is listed as a Key Threatening Process under the Threatened Species Conservation Act.

6. Banksia conferta subsp.  conferta is threatened in NSW by environmental and demographic stochasticity due to its very highly restricted distribution and small population size. Fire regimes may pose a threat if successive fires burn large portions of the population within periods of time less than about one decade. Road maintenance and fire management operations also pose a potential threat to parts of the population adjacent to roadsides. It may be inferred from these threats that  Banksia conferta subsp.  conferta is suffering a continuing decline or will suffer a projected decline in abundance, geographic distribution or habitat quality.

7. Banksia conferta A.S George subsp . conferta 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:

(i) an index of abundance appropriate to the taxon,
(ii) geographic distribution, habitat quality or diversity, or genetic diversity; and

(e) the following two conditions apply:

(ii) all or nearly all mature individuals are observed or inferred to occur within a small number of populations or locations,
(iii) extreme fluctuations are observed or inferred to occur in :

(A) an index of abundance appropriate to the taxon.

Professor Lesley Hughes
Chairperson
Scientific Committee

Proposed Gazettal date: 10/08/07
Exhibition period: 10/08/07 - 28/09/07

References 

George AS (1981) The genus Banksia L.f. (Proteaceae).  Nuytsia 3, 239-473.

George AS (1999) Banksia. In: 'Flora of Australia 17B' (Ed. A Wilson), pp. 175-251. (ABRS, Canberra/CSIRO: Melbourne.)

Griffith SJ (2005) Banksia  conferta subsp.  conferta in Coorabakh National Park: Preliminary observations and guidelines for fire management. Report to the Manning Area of the Parks and Wildlife Division, Department of Environment and Conservation (NSW).

Keith DA (1996) Fire-driven mechanisms of extinction in vascular plants: a review of empirical and theoretical evidence in Australian vegetation. Proceedings of the Linnean Society of New South Wales 116, 37-78.