Hibbertia stricta subsp furcatula - endangered species listing
The Scientific Committee, established by the Threatened Species Conservation Act, has made a Final Determination to list the shrub Hibbertia sp. nov. 'Menai' A.T. Fairley 15 Dec 2004 as an ENDANGERED SPECIES in Part 1 of Schedule 1 of the Act. Listing of endangered species is provided for by Part 2 of the Act.
This species is now known as Hibbertia stricta subsp. furcatula Toelken [NSW Government Gazette No. 183, 27 December 2013, Page 6019].
NSW Scientific Committee – final determination
The Scientific Committee has found that:
1. Hibbertia sp. nov. 'Menai' (family Dilleniaceae) is a small shrub 0.8 - 1.3 m in height and up to 70 cm wide, usually of strict upright habit, and densely covered with hairs on the branchlets, sepals, carpels, and (less densely) leaves, the hairs lacking a basal tubercle and reduced-stellate on type, with two or three stiff strongly ascending to erect arms (or rarely simple), the hairs and arms sometimes tending antrorsely directed. Branchlets are pale orange-brown, angular near the tips, with ridges produced downwards from the base of each leaf. Leaves are alternate, linear, 7 - 15 mm long, 0.5 - 0.8 mm wide, with the margin entire and recurved; the adaxial (upper) surface is slightly sunken along the midrib, venation not otherwise visible; the abaxial (lower) surface has the midvein up to 1.5 times as broad as the 'rolled' margins and somewhat sunken between them, with a deep distinct groove along either side; the leaves are unevenly spaced and often appearing somewhat whorled; each leaf sits on a cupped protuberance from the stem. Flowers are solitary, mostly on short lateral branchlets and terminal (but sometimes appearing axillary), sessile or very shortly pedicellate (pedicel up to 0.5 mm long). Sepals are hairy outside except near margin, glabrous inside, narrowly ovate, 4.5 - 7 mm long, 1.5 - 2.5 mm wide, the two 'outer' sepals slightly narrower than the other three; margin entire; apex with a short to long point; outer surface sometimes slightly ridged along the midline, papery, green to margin on the two 'outer' sepals, or with a distinct pale margin 0.5 mm wide on the other three. Petals are obovate, 4 - 6.5 mm long, c. 3 mm wide, yellow, with midvein pale orange-coloured. Stamens are 6 - 8, inserted to one side of the carpels; filaments 0.5 - 0.7 mm long; anthers 2 - 3 mm long. Carpels 2, 0.8 - 1 mm long, densely hairy (as for other parts); styles laterally inserted, c. 3 mm long.
2. Hibbertia sp. nov. 'Menai' is most similar and probably most closely related to H. stricta R.Br. sensu stricto. Both taxa have in recent years, with some other suspected undescribed taxa, been regarded as part of the species complex around H. riparia (R.Br. ex DC.) Hoogl. (e.g. Harden and Everett 2000: p 302). Taxonomic work (H. Toelken, South Australian Herbarium, pers. comm.) is resolving this complex, and validates the taxonomic distinctiveness of Hibbertia sp. nov. 'Menai'. H. stricta R.Br. sens. strict. differs from the 'Menai' taxon in having a more prominent and proportionately wider midvein on the lower (abaxial) surface of the leaf, completely filling the space between the revolute leaf margins and often overtopping them, and in having branches, leaves and sepals with smaller multi-angulate reduced-stellate hairs, these usually simple or with two (very rarely three) very short arms, the hairs and arms, strongly antrorse to weakly spreading, and only weakly emergent from a basal tubercle (sometimes the arms scarcely or not emergent, and the leaf upper surface effectively hairless); the hairs are in almost all cases less densely distributed on the leaf surface than in the Menai taxon. H. stricta sens. str. occurs in more maritime situations, being known from the north shore of Port Jackson ('Quarantine Ground', JH Maiden, 1889), the eastern suburbs of Sydney, the Jervis Bay area, from north of Milton to Ulladulla, Snapper Point, and extending inland near Batemans Bay to near Currowan Creek. There are also disjunct single specimens apparently assignable to H. stricta sens. str. from the NSW far South Coast (Womboyn/Genoa River, MEL35941) and from 'Diamond Head' (E. Duncan 29 Apr. 1968, CBG 023942) - possibly the locality of that name on the mid-North Coast.
3. Hibbertia sp. nov. 'Menai' flowers from July to about December. It appears to propagate by seed, with no evidence to date of vegetative reproduction or regeneration. Its longevity, seed biology, and most aspects of its ecology are unknown, although in common with most species of Hibbertia it is probably pollinated primarily by bees. Recruitment appears to be continuing in at least one site in Menai that is very disturbed by road verge construction and maintenance (R.O. Makinson pers. comm.), with young plants flowering at an estimated two years of age and others at the site with an estimated age of 6-8 years.
4. Hibbertia sp. nov. 'Menai' is known to occur in two metapopulations, one in the southern outskirts of Sydney, and one near Nowra on the mid-South Coast of NSW. The Southern Sydney metapopulation occurs on both sides of the Woronora River gorge. A northern sub-population (96 plants known at 20 January 2006: L. Hedges, Menai Wildflower Group, pers. comm.) occurs in the Menai-Bangor area, and in the adjacent suburbs of Alfords Point (Mill Creek catchment) and Illawong (Still Creek catchment). The southern sub-population (c. 90 plants known at 20 Jan. 2006, L. Hedges pers. comm., M. Bradhurst pers. comm.) is in Maandowie Reserve, Loftus, a local government reserve. The South Coast metapopulation is less well known, but herbarium specimen records show it occurring just to the west and south-west of Nowra, with most of the six collections made prior to 1970.
5. Habitat of the Southern Sydney metapopulation is broadly dry sclerophyll forest and woodland. Dominant tree species at various sites include Corymbia gummifera, Angophora costata, Eucalyptus resinifera, E. piperita and Allocasuarina littoralis. Associated shrub and ground layer species recorded at various sites include Acacia linifolia, Acacia myrtifolia, Acacia suaveolens, Actinotus helianthi, Actinotus minor, Astroloma sp., Banksia spinulosa, Bauera rubioides, Caustis flexuosa, Dodonaea triquetra, Gonocarpus sp., Grevillea sericea subsp. sericea, Grevillea buxifolia subsp. buxifolia, Grevillea mucronulata, Hardenbergia violacea, Lasiopetalum ferrugineum, Leptospermum sp., Lomandra longifolia, Platysace lanceolata and Xanthosia pilosa. This metapopulation appears to occur mainly on upper slopes and above the Woronora River gorge escarpment, at or near the interface between the Lucas Heights soil landscape and Hawkesbury sandstone. Habitat of the South Coast metapopulation is poorly recorded, but appears to be dry sclerophyll forest or woodland associations in sandy soils over sandstone, with one record from gravelly clay soil.
6. The very recent recognition of Hibbertia sp. nov. 'Menai' as a distinct taxon makes difficult a reconstruction of past distribution and any decline, the few herbarium records being the only firm information source and these lacking much population data. However, scarcity of past collections suggests that the taxon has always been fairly uncommon and restricted in distribution. The scale of urban development in recent decades in both metapopulation areas, and the surviving occurrences in the Menai/Bangor area alongside recently constructed roadways and housing estates, suggests that there has been significant recent destruction of suitable habitat and a high probability of significant recent declines in both numbers of plants and areas of occupancy. Several of the surviving sites in the Menai/Bangor area are in small disturbed bushland remnants with very low numbers of plants, and are threatened by weeds, road verge maintenance work (potentially including weed spraying), trampling, changed fire regime, and changed drainage patterns. Tenures for these sites are yet to be fully determined but are apparently mainly a mix of Road Transport Authority and Council easements. Pressures operating on the Loftus sub-population (mostly or wholly in a Council reserve) are yet to be evaluated. Similar urbanisation pressures may be operating on the South Coast metapopulation; most of the six confirmed collections were made close to the Nowra urban area before the major westward expansion of that town from the 1970s. Susceptibility of the species to pathogens is not known. The species is not confirmed as occurring in any conservation reserve; although one herbarium record for the South Coast metapopulation (I. Beeton 23 Aug. 1969, CBG 043381) gives a possibly erroneous location as 'Morton National Park'.
7. The Scientific Committee is of the opinion that Hibbertia sp. nov. 'Menai' is not eligible to be listed as a critically endangered species.
8. Hibbertia sp. nov. 'Menai' A.T. Fairley 15 Dec 2004 is eligible to be listed as an endangered species as, in the opinion of the Scientific Committee, it is facing a very high risk of extinction in New South Wales in the near 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:
(b) highly restricted
and:
(d) a projected or continuing decline is observed, estimated or inferred in:
(i) an index of abundance appropriate to the taxon, and
(ii) geographic distribution and habitat quality
(e) the following two conditions apply:
(i) the population or habitat is observed or inferred to be severely fragmented;
(ii) all or nearly all mature individuals are observed or inferred to occur within a small number of populations or locations
Clause 16
The estimated total number of mature individuals of the species is:
(b) low,
and:
(d) a projected or continuing decline is observed, estimated or inferred in:
(i) an index of abundance appropriate to the taxon, and
(ii) geographic distribution and habitat quality
(e) the following two conditions apply:
(i) the population or habitat is observed or inferred to be severely fragmented;
(ii) all or nearly all mature individuals are observed or inferred to occur within a small number of populations or locations
Professor Lesley Hughes
Chairperson
Scientific Committee
Proposed Gazettal date: 10/08/07
Exhibition period: 10/08/07 - 28/09/07
Reference:
Harden GJ and Everett J (2000) 28. Dilleniaceae. In 'Flora of New South Wales vol. 1', revised edition (ed. GJ Harden) (University of New South Wales Press: Sydney)