North Rothbury Persoonia Persoonia pauciflora - critically endangered species

The Scientific Committee, established under the Threatened Species Conservation Act, has made a Final Determination to list the North Rothbury Persoonia Persoonia pauciflora P.H. Weston, as a CRITICALLY ENDANGERED SPECIES in Part 1 of Schedule 1A of the Act, and as a consequence to omit reference to Persoonia pauciflora P.H. Weston 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.

The Scientific Committee has found that:

1. The North Rothbury Persoonia Persoonia pauciflora P.H. Weston (Proteaceae) was first discovered in 1997 in the Hunter Valley, NSW. In 1999 it was listed as an endangered species in NSW under the Threatened Species Conservation Act and in 2005 as a critically endangered species under the Environment Protection and Biodiversity Conservation Act 1999.

2. P. pauciflora is a small spreading shrub occurring on clay soils derived from silty sandstones of the Farley Formation in dry sclerophyll forest or woodland with a shrubby or open understorey in the Hunter Valley area (Patrick 2000). P. pauciflora is described by Weston (1999) as follows: "Spreading, apparently non-lignotuberous shrubs, 0.4 - 1.4 m high, 0.4 - 2.0 m wide; bark smooth, grey. Hairs 0.05 - 0.7 mm long, greyish, mostly antrorsely appressed but a minority being antrorsely spreading. Immature stems moderately hairy; internodes 0 - 7 (-14) mm long. Leaves alternate, linear-filiform, acuminate, (0.3-)1.7 - 3.5 cm long, (0.4-) 0.6 - 0.8 mm wide, terete when living, compressed and grooved underneath when dried, spreading to suberect and usually slightly to moderately incurved, more or less laterally symmetrical, not twisted, not pungent, bright green when fresh, olive green when dried, concolorous, sparsely to moderately hairy when immature, sparsely hairy to glabrescent when mature, smooth; venation obscure. Inflorescences growing from terminal or lateral buds, auxotelic, 1 - 9 flowered; rachis 0 - 1.1 cm long; flowers mostly subtended by reduced leaves but more distal flowers in an inflorescence sometimes subtended by full - sized leaves. Pedicels 0.7 - 2.5 mm long, antrorsely spreading, moderately hairy, green when living. Perianth actinomorphic, the tepals 4.5 - 8.0 mm long, acute, not keeled, moderately hairy on the abaxial surface, dull yellow; terminal points 0 - 0.1 mm long. Anthers lacking appendages, held close to one another and to the gynoecium at their bases but recurved at the tips, dull yellow; loculi 2.0 -4.0 mm long. Gynoecium straight, 4.0 -7.0 mm long; ovary glabrous; ovule 1. Drupes dull green or green with reddish purple striations, glabrous; pyrene broad-obovoid to broad-ellipsoid, 9.4 - 11.1 mm long, 4.6 - 5.5 mm wide. Seed 1; cotyledons 4 - 7."

3. Weston (1999) states that P. pauciflora most closely resembles P. isophylla and to a lesser extent P. pinifolia. P. pauciflora is most easily distinguished from these species by its inflorescence, which has fewer flowers and is shorter. Weston (1999) provides an amendment to published keys for Persoonia in order to accommodate P. pauciflora.

4. P. pauciflora flowers from October to May. Flowers are generally produced within 18 months to three years from germination. Its breeding system is unknown but it is likely that native bees are required for pollination. Seedlings are present in most sub-populations indicating that the species is capable of reproducing when conditions are suitable. Its fire ecology is unknown but it is likely to be killed by fire, as are other smooth-barked Persoonias, including P. pinifolia and P. isophylla. Monitoring since 1999 has revealed considerable fluctuations in the number of mature individuals over time and P. pauciflora is considered likely to be a obligate seeder (Patrick 2006). The standing plants of P. pauciflora appear to have a relatively short lifespan of around 7-12 years (G. Patrick pers. obs.). Macropods have been observed grazing on new growth and may also disperse the succulent fruits. Seeds may also be dispersed by birds and ants (G. Patrick pers. obs.). P. pauciflora appears to be sensitive to disturbance such as grazing and slashing (Patrick 2006). Specimens are rarely present in disturbed areas where introduced species are dominant, particularly grasses on roadside verges (Patrick 2006).

5. P. pauciflora is currently known only from near North Rothbury in the Hunter Valley in the Cessnock local government area. Based on the extent of the soils derived from the Farley Formation to which the species is thought to be restricted, the species is estimated to have had approximately 4200 ha of potential habitat prior to settlement of the area (Patrick 2000). At the time of listing as an endangered species in 1999 the total number of plants was estimated to be approximately 400 individuals (Patrick 1999). At this time, all but one of the individuals occurred within a 2.5 km radius of the originally discovered specimen. Within this very highly restricted geographic distribution, there were three main sub-populations comprising approximately 90% of the total population. The remaining 10% of the population occurred as scattered individuals in a relatively disturbed landscape.

6. Since the original listing, several surveys for the species have taken place in the Cessnock and Singleton local government areas (including Patrick 1999, 2000 and 2006). No additional populations have been recorded either in the North Rothbury/Branxton area or from further afield.

7. The entire known population of P. pauciflora is very highly restricted, occupying a total range of approximately 450 ha with the exception of a small number of individuals about 2.5 km to the north of the main aggregation (Patrick 2006). The area of occupied habitat within the 450 ha range is less than 50 ha (Patrick 2006). Forty five percent of individuals occur within council-managed road reserves with the remaining 55% occurring on private property zoned Rural. Given the restricted area of the road reserves, it is estimated that approximately 93% of all occupied habitat occurs on private property. None of the individuals currently occur in a formal conservation reserve.

8. In late 2006 the total population P. pauciflora was estimated to include approximately 350 mature individuals (Patrick 2006). This estimate is likely to contain a number of hybrid specimens (3-5%) which are unable to produce viable seed (Patrick 2006). Approximately 100 seedlings and juvenile plants located across the species range are also known (Patrick 2006). The population is severely fragmented with individuals spread across at least 18 sites; of these, only two sites support more than 21 individuals. These two sites currently have 140 and 90 mature individuals respectively.

9. Overall population numbers have fluctuated over time. There was an increase in mature specimens recorded between 1997-8 and 2001 (33-350), but this estimate decreased to between 80 and 125 individuals in 2002 (Patrick 2006). These fluctuations have apparently been associated with environmental variation, such as drier and wetter periods.

10. Between December 2005 and June 2006 approximately 270 individuals were illegally removed from one of the sites in the North Rothbury area. A systematic survey in June 2006 located fewer than 20 P. pauciflora plants remaining at this site. A previous survey of the site in December 2005 indicated that it had supported more than 280 individuals.

11. The species is threatened by habitat fragmentation, habitat degradation, grazing, slashing, residential development and clearing, both legal and illegal. Within the past three years the species has undergone a very large reduction in total population size with at least 280 individuals lost to residential development or alleged unauthorised removal. At least 6 of the sites occupied by the species are currently subject to development applications, potentially affecting 37% of individuals and 78% of occupied habitat. The increasing subdivision of lots within the North Rothbury area is of particular concern given the susceptibility of P. pauciflora to disturbance. Over the longer term, the species is also potentially threatened by the demographic and environmental stochasticity associated with such a restricted distribution and small total population size.

12. P. pauciflora P.H. Weston 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 14

The species has undergone, is observed, estimated, inferred or reasonably suspected to have undergone, or is likely to undergo within a time frame appropriate to the life cycle and habitat characteristics of the taxon:

(a) a very large reduction in population size,

based on:

(d) an index of abundance appropriate to the taxon

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;

(e) at least two of the following three 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,

    (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: 07/09/07

Exhibition period: 07/09/07 - 02/11/07

References:

Patrick G (1999) Initial flora survey to sample potential habitat, abundance and distribution of new plant species Persoonia 'North Rothbury'. Report to the NSW NPWS Hurstville.

Patrick G (2000) Survey of the threatened species Persoonia pauciflora within the northern and central portions of the Cessnock City Council Area. Report to the NSW National Parks and Wildlife Service, Hurstville.

Patrick G (2006) Collation of information on the Status of the Endangered Species Persoonia pauciflora in the Lower Hunter Valley of NSW. Report to the Department of Environment and Conservation (NSW).

Weston PH (1999) Persoonia pauciflora (Proteaceae) a new species from the Hunter Valley, New South Wales. Telopea 8, 159-164.

More information

Page last updated: 28 February 2011