Hibbertia fumana - critically endangered species listing

NSW Threatened Species Scientific Committee - final determination

The NSW Threatened Species Scientific Committee has found that:

1. Hibbertia fumana Sieber ex Toelken (family Dilleniaceae) has been described by Toelken and Miller (2012) as a “Decumbent shrublet, prostrate, with many branches from the base, moderately to much branched; branches, wiry, with raised leaf bases shortly decurrent, shortly fascicled-pubescent. Vestiture persistent, consisting of more or less coarse simple hairs over fine fascicled hairs on tubercles; on branches more or less densely covered with short subequal multiangulate fascicled hairs (4–7 equal arms) and without simple hairs except for intrapetiolar tufts of hairs in leaf axils; on leaves above scattered, short antrorse fine bi- or triforked to simple hairs, sparse becoming denser onto the petiole, few simple hairs along the flanks, all wearing off soon; on leaves below dense, with short subequal multiangulate fascicled hairs (4–12 subequal arms) particularly on central vein, overtopped by few simple hairs on the flanks of the revolute margins; on outer calyx moderately outside dense, with spreading coarse antrorse simple hairs over erect-spreading multiangulate fascicled hairs (8–15 subequal arms), inside dense, with forked to simple antrorse hairs over most of surface; on inner calyx lobes outside dense with spreading multiangular fascicled hairs (2–12 subequal or unequal arms) becoming smaller towards the membranous margins, overtopped by coarse antrorse simple hairs along the central ridge, inside glabrous except for a few simple hairs towards the apex. Leaves with intrapetiolar axillary tuft of hairs up to 0.7 mm long; petiole 0.2–0.45 mm long; lamina narrowly oblong, rarely linear-elliptic, (1.9–) 2.1–3.1 (–3.3) × 0.5–0.8 mm, obtuse, with terminal tuft on a somewhat recurved apex of the central vein, more or less abruptly constricted into petiole, above ± flat and puberulous to glabrescent, below with broadened central vein recessed below the level of revolute margins and protruding into apex, pubescent to puberulous. Flowers single, terminal, commonly on main branches; flower stalk 2–8 mm long, recurved and elongating after flowering; bract linear to linear-triangular, 1–1.3 mm long, fascicled-pubescent, on lower third of flower stalk. Calyx distinctly accrescent, with lobes subequally long; outer calyx lobes lanceolate, 4.5–5.7 × 1.3–1.65 mm, acute to acuminate, without ridge, outside strigosepubescent, inside finely strigose with antrorse forked hairs on much of the surface; inner calyx lobes oblong-ovate, 4.5–5.8 × 3.1–3.5 mm, usually cuspidate, outside strigose along the central vein and tomentose towards the margins, inside glabrous with few forked hairs at the apex. Petals obovate, 4–5.2 mm long, broadly bilobed. Stamens 5 or 6 (7), subequal, clustered on one side of the ovaries; filaments 0.4–0.6 mm long, basally connate; anthers broadly oblong, 1.3–1.4 mm long, ± abruptly constricted above and below. Pistils 2; ovaries obovoid but ± laterally compressed, each with 4 ovules, fascicled-tomentose, with style attached to dorsal apex then base recurved to the base and up on either side of the stamens with stigmas exposed above the anthers. Fruit and seeds unknown”.

2. Hibbertia fumana is endemic to New South Wales (NSW) and was considered to be extinct when described by Toelken and Miller (2012) as, at the time of description, the species was known from only three herbarium collections made in the early 19th Century. Two of these had vague collection details (viz. “near Sydney” and “occidental [western] Sydney”) and the third came from “near South Head”.

3. Hibbertia fumana was rediscovered at the Moorebank Intermodal Terminal Precinct (SIMTA) in Moorebank, south-western Sydney, during flora surveys in October 2016 (see Duretto et al. 2017). This site was re-surveyed in November 2016 when c. 370 individuals were located growing in the transition zone between Castlereagh Ironbark Forest and Castlereagh Scribbly Gum Woodland in the Sydney Basin Bioregion (a listed Vulnerable Ecological Community under the Act) and with H. puberula (a listed Endangered species under the Act) (A. Orme in litt. November 2016, J. Rodd in litt. February 2017). The population occupies an area of c. 5 ha (A. Orme pers. comm. November 2016).

4. Little is known about the life history of Hibbertia fumana. Seed production and plants of different ages were recorded within the only known population (A. Orme in litt. November 2016). The species does sucker (A. Orme in litt. November 2016) suggesting it may be able to resprout from rootstock following fire.

5. Hibbertia fumana appears to have had a significant reduction in distribution over the last 200 years. Historically it was more widespread being recorded from both eastern (South Head) and western Sydney but is now believed to be extinct at South Head. It is unknown if the historic western Sydney collection was made in the same area as the extant population. Since there have been very few records of this species, it may always have been rare and/or has suffered significant habitat loss during the early growth of Sydney.

6. The distribution of Hibbertia fumana is very highly restricted. As there is only one known extant population, the area of occupancy (AOO) and the extent of occurrence are both estimated to be 4 km2 . The AOO is based on a single 2 x 2 km grid cell, the scale recommended for assessing AOO by IUCN (2016).

7. The only known population of Hibbertia fumana is within the Moorebank Intermodal Terminal Precinct and is potentially threatened by habitat loss and degradation. Habitat at the site is disturbed with the population being traversed by a railway line. Infrastructure work in the area is likely to result in further habitat loss and disturbance which is likely to facilitate weed invasion (Lake and Leishman, 2004). Alterations to fire regimes in this isolated habitat fragment may also adversely affect the species. ‘Clearing of native vegetation’ and ‘High frequency fire resulting in the disruption of life cycle processes in plants and animals and loss of vegetation structure and composition’ are listed as a Key Threatening Processes under the Act.

8. Hibbertia fumana Sieber ex Toelken is eligible to be listed as a Critically Endangered species as, in the opinion of the NSW Threatened Species Scientific Committee, it is facing an extremely high risk of extinction in Australia in the immediate future as determined in accordance with the following criteria as prescribed by the Biodiversity Conservation Regulation 2017:

Clause 4.3 - Restricted geographic distribution of species and other conditions (Equivalent to IUCN criterion B)

Dr Marco Duretto
Chairperson
NSW Threatened Species Scientific Committee

Exhibition period: 01/12/17 – 26/01/18
Proposed Listing date: 01/12/17

References:

Duretto MF, Orme AE, Rodd J, Stables M, Toelken H (2017) Hibbertia fumana (Dilleniaceae), a species presumed to be extinct rediscovered in the Sydney region, Australia. Telopea 20, 143- 146.

IUCN Standards and Petitions Subcommittee (2016) Guidelines for Using the IUCN Red ListCategories and Criteria. Version 12. Prepared by the Standards and Petitions Subcommittee.

Lake JC, Leishman MR (2004) Invasion success of exotic plants in natural ecosystems: the role of disturbance, plant attributes and freedom from herbivores. Biological Conservation 117, 215– 226.

Toelken HR, Miller RT (2012) Notes on Hibbertia (Dilleniaceae) 8. Seven new species, a new combination and four new subspecies from subgen. Hemistemma, mainly from the central coast of New South Wales. Journal of the Adelaide Botanic Gardens 25, 71–96.

A notice of determination to provisionally list this species as an critically endangered species was gazetted on 16/12/16