Zieria parrisiae - critically endangered species listing
The Scientific Committee, established by the Threatened Species Conservation Act, has made a Final Determination to list the shrub Zieria parrisiae J.D. Briggs & J.A. Armstr. as a CRITICALLY ENDANGERED SPECIES in Part 1 of Schedule 1A of the Act, and as a consequence, to omit reference to Zieria parrisiae J.D. Briggs & J.A. Armstrong from Part 1 of Schedule 1 (Endangered species) 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. Zieria parrisiae J.D.Briggs & J.A.Armstr. (family Rutaceae) has been described by Armstrong (2002) as:
‘A many-branched shrub up to 3 m; younger branches not ridged, densely tuberculate, pubescent all over with short stellate hairs, the stems and tubercules often with a reddish tinge; older branches becoming etuberculate, glabrescent. Leaves palmately trifoliolate, opposite, petiolate. Petiole (1.5) 2.0-4.0 (5.0) mm long, densely tuberculate, with a dense velvety indumentum of very short stellate hairs. Central leaflet narrow oblanceolate-lanceclate (18) 25-35 (44) x (1.5) 3.0-4.0 (5.5) mm, dark green above, paler green beneath; upper surface densely tuberculate, pubescent with very short stellate hairs; the primary vein deeply sunken, the secondary veins slightly sunken; lower surface densely tuberculate, with a dense velvety indumentum of short stellate hairs; apex acute to obtuse; margin somewhat dentate (because of the large tubercules), recurved; primary vein prominently raised, densely tuberculate and densely stellate-pubescent, secondary veins slightly raised and less conspicuous. Secondary leaflets similar to central leaflet but smaller, usually 0.75-0.85 times as long. Inflorescence axillary, almost as long as the leaves (3) 9-24 (33)-flowered. Peduncle (3) 10-15 (16) mm long, densely tuberculate, densely pubescent with short stellate hairs. Bracts generally deciduous (only one bract or bracteole present at each node of the inflorescence), narrow lanceolate to oblanceolate, 2.0-5.0 x 0.5-1.0 mm, tuberculate on the lower surface only, moderately to densely stellate-pubescent, foliaceous but very much smaller. Pedicel terete, 2.5-5.0 mm long, sparsely tuberculate, moderately pubescent with very short stellate hairs. Flowers white, conspicuous, 7.0-9.0 mm diameter. Calyx lobes deltoid, 1.3-1.8 x 1.0-1.3 mm, very much shorter than the petals, tuberculate and stellate hairy on the outer surface, etuberculate and glabrous on the inner surface. Petals imbricate in bud, ovate-elliptic, 4.0 x 2 mm with a small inflexed mucro at the apex, both surfaces with a fine pubescence of very short stellate hairs. Stamens not persisting in the fruiting stage; filaments 1.5-1.8 mm long, glabrous, not warty or tapering; anthers 0.7 x 0.6 mm, not apiculate, attached in the lower third, deep orange in colour (cream in dry state). Disc interrupted and distinct, glabrous, white. Ovary not tuberculate, glabrous. Style c. 0.5 mm long, glabrous. Stigma 0.3 mm broad, lobed. Fruit reddish-brown when immature, becoming green at maturity, densely tuberculate on carpel surface, glabrous. Cocci lacking an appendage. Seed grey to grey-brown, striate, 1.8 x 1.3 mm; covering to the raphe shiny black, not striate. Seed surface: ridges well-developed, flattened and not prominent, short; branches and cross-ridges common, wax present. Elaiosome 1.3 x 1.0 mm.’
2. Zieria parrisiae was first discovered in 1986. The species has been known by a number of informal names, including ‘ Z. parrisiae J. D. Briggs & J. A. Armstr. ms (Armstrong 5091)’ (Armstrong & Harden 2002), ‘Z. species I’ (Armstrong 1991), ‘Z. sp. 15’ (Briggs & Leigh 1988) and ‘Z. sp. Q (Box Range North)’ (J.D. Briggs pers. comm. 2008). Zieria parrisiae is distinguished from closely related Z. buxijugum and Z. formosa by the less velvety coverage of stellate hairs on the upper surface of its leaves, and from Z. tuberculata by the presence of prominent warts on its fruits.
3. Zieria parrisiae is endemic to New South Wales and is restricted to a single population on private land, west of Pambula. Further surveys in and around the area have failed to locate any additional populations (Briggs & Leigh 1990; NSW NPWS 2002; J.D. Briggs pers. comm. 2008).
4. Zieria parrisiae grows in skeletal, grey, sandy loam amongst broken rhyolite rocks and boulders, in the ecotone between shrubby heath and open dry sclerophyll forest (Briggs & Leigh 1990; NSW NPWS 2002). The species flowers prolifically between late September and early November (Briggs & Leigh 1990; Armstrong 2002; NSW NPWS 2002). Its fire response is unknown, however many species of Zieria are killed by fire. Plants have been observed to resprout after defoliation following browsing.
5. The population of Z. parrisiae includes an extremely low to very low number of mature individuals. When last surveyed in 2001, the population included 36 mature individuals and 85 smaller plants. The extent of occurrence and area of occupancy are each estimated at 4 km2, based on 2 x 2 km grid squares, the spatial scale recommended for assessing areas of occupancy IUCN (2008).
6. Zieria parrisiae is threatened by demographic and environmental stochasticity due to its very highly restricted distribution and extremely low mature population size. Browsing by feral goats caused a major population decline in the 1980s before the goats were removed from the area (Briggs & Leigh 1990; Armstrong 2002; NSW NPWS 2002). The population was further threatened by browsing by Swamp Wallabies ( Wallabia bicolor) until a fence was constructed around it in 2002. The integrity of the fence is infrequently inspected to determine whether it remains an effective barrier. Potential breaches to the fence caused by treefall or vandalism may therefore go undetected for some time. Given the risks associated with the known impact of browsing on the population, the uncertain security of the fence, and the uncertain management practices that may accompany future changes in ownership, the species is projected to undergo a future decline (J.D. Briggs pers. comm. 2008). ‘Competition and habitat degradation by Feral Goats , Capra hircus Linnaeus 1758’ is listed as a Key Threatening Process under the Threatened Species Conservation Act 1995.
7. Zieria parrisiae J.D. Briggs & J.A. Armstr. 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
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:
(i) an index of abundance appropriate to the taxon
(ii) geographic distribution, habitat quality or diversity, or genetic diversity
Clause 17
The total number of mature individuals of the species is observed, estimated or inferred to be:
(a) extremely low.
Dr Richard Major
Chairperson
Scientific Committee
Proposed Gazettal date: 31/07/09
Exhibition period: 31/07/09 – 25/09/09
References:
Armstrong JA (1991) Zieria. In ‘Flora of New South Wales. Volume 2’. (Ed. GJ Harden). (University of New South Wales Press: Kensington).
Armstrong JA (2002) Zieria (Rutaceae): a systematic and evolutionary study. Australian Systematic Botany 15, 277-463.
Armstrong JA, Harden GJ (2002) Zieria. In ‘Flora of New South Wales. Volume 2’. (Ed. GJ Harden). (University of New South Wales Press: Kensington).
Briggs JD, Leigh JH (1988) Rare or threatened plants: 1988 revised edition. Australian National Parks and Wildlife Service Special Publication No. 14, Canberra.
Briggs JD, Leigh JH (1990) Delineation of Important Habitats of Threatened Plant Species in South-Eastern New South Wales. Australian Heritage Commission, Canberra.
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)
NSW NPWS (2002) ‘Draft Recovery Plan for Zieria formosa, Zieria buxijugum and Zieria parrisiae.’ NSW National Parks and Wildlife Service, Hurstville NSW.