Zieria odorifera subsp. copelandii, a shrub - critically endangered species listing

The NSW Threatened Species Scientific Committee, established under the Biodiversity Conservation Act 2016 (the Act), has made a Final Determination to list the shrub Zieria odorifera subsp. copelandii Duretto & P.I.Forst. as a CRITICALLY ENDANGERED SPECIES in Part 1 of Schedule 1 of the Act. Listing of Critically Endangered species is provided for by Part 4 of the Act.

NSW Threatened Species Scientific Committee - final determination

The NSW Threatened Species Scientific Committee has found that:

1. Zieria odorifera subsp.  copelandii Duretto & P.I.Forst. (family Rutaceae) is an erect shrub to 20 cm tall. Branches ridged, with a sparse indumentum of simple, bifid and stellate hairs between the ± glabrous leaf decurrencies. Leaves trifoliate, with a few simple hairs on midvein and/or margin; petioles 1–1.5 mm long, weakly glandular verrucose; terminal leaflets narrow elliptic to narrow oblanceolate to oblanceolate, 5–8.5 × 1.5–3.5 mm, margins entire to slightly glandular dentate, adaxial surface not glandular verrucose. Inflorescence usually about equal to subtending leaves, 1–3(–7)-flowered, peduncle 3–7 mm long, with simple and bifid hairs concentrated between decurrent bract bases; pedicels 1.5–3.5 mm long, with a sparse to moderately dense stellate indumentum. Sepals 1–1.5 × 1–1.3 mm, abaxial surfaces glabrous or with few stellate hairs towards base. Petals c. 3.5 × 1.7 mm, adaxial surface glabrous or glabrescent, abaxial surface glabrous or with a few hairs near margins. Gynoecium glabrous. Cocci smooth, glabrous (Duretto and Forster 2008; PlantNET 2016).

2. Zieria odorifera subsp.  copelandii is endemic to New South Wales (NSW) and is known from a single population in Mount Kaputar National Park near Narrabri in northern NSW, growing in heath with  Prostanthera cruciflora,  Calytrix tetragona and  Kunzea sp. on rocky slopes near rock outcrops (Duretto and Forster 2008; PlantNET 2016; L. Copeland  in litt. May 2016, November 2016, January 2017). There are three herbarium collections of this taxon: two of these are known to come from the known population and the third has vague locality information that places it in the general area of the known population.

3. Surveys for Zieria odorifera subsp.  copelandii in October 2012 and 2014 located 15 individuals over an area of 1 ha (L. Copeland  in litt. May 2016, November 2016, January 2017). The number of mature individuals is therefore estimated to be extremely low.

4. The distribution of Zieria odorifera subsp.  copelandii is very highly restricted. 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).

5. The only known population of Zieria odorifera subsp.  copelandii is threatened by grazing by feral goats and inappropriate fire regimes (L. Copeland,  in litt. May 2016, January 2017). The population’s small size and limited distribution make it highly susceptible to localised events such as clearing, disturbance and weed invasion. The only known population is located near a road and road works could have a major negative impact on the population. ‘Clearing of native vegetation’, ‘Competition and habitat degradation by Feral Goats,  Capra hircus Linnaeus 1758’ 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 Key Threatening Processes under the Act.

6. Zieria odorifera subsp.  copelandii Duretto & P.I.Forst. 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 4.5 - Low total numbers of mature individuals of species (Equivalent to IUCN criterion D)

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, Forster PI (2008) New subspecies for Zieria odorifera J.A.Armstr. (Rutaceae) from northern New South Wales. Austrobaileya 7, 681–690.

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

PlantNET (The NSW Plant Information Network System) Royal Botanic Gardens and Domain Trust, Sydney (accessed 24 November 2016).