Dracophyllum macranthum - vulnerable species listing

NSW Scientific Committee - final determination

The Scientific Committee, established by the Threatened Species Conservation Act, has made a Final Determination to list the shrub Dracophyllum macranthum E.A.Br. & N.Streiber as a VULNERABLE SPECIES in Part 1 of Schedule 2 of the Act. Listing of vulnerable species is provided for by Part 2 of the Act.

 

The Scientific Committee has found that:

 

1. Dracophyllum macranthum E.A.Br. & N.Streiber is a weakly woody open shrub 0.6-2 (rarely 3) m tall, often branching near the base, initially erect to spreading but the longer branches frequently pendent or decumbent. The branches are often reddish brown towards the tips. The leaves are light- to mid-green, erect to spreading, often gently down-curved, linear or narrowly triangular, 9-20 mm long, 6-9 mm wide, flat to concave, with a finely serrulate (toothed) margin; the leaves are often concentrated on the apical 20-30 cm of stem. The inflorescence is narrow, terminal, and spike-like, 5-15 cm long, with about 10-40 tubular flowers borne on pedicels 1-3 mm long, 1-3 flowers per node, each node with a large reddish-brown triangular bract to 50 mm long and 10 mm wide; the flowers tend to be held on one side of the inflorescence axis, and have a rose-coloured calyx and a pink corolla (becoming red with age) with five white apical lobes; the corolla tube is 16-25 mm long and 3-4 mm diameter, the lobes ovate and spreading and 2.5-4 mm long; the anthers are held within the throat of the corolla tube; the pistil (style) is slightly longer than and emergent from the corolla tube. The fruit is reddish brown, shorter than the calyx tube; seeds are minute. A full description and line illustration are in Brown & Streiber (1999). Flowering occurs in August-September (possibly also October).

 

2. The phrase name Dracophyllum sp. ‘Lansdowne’ (Brown 97/51) was applied to D. macranthum prior to publication, e.g. in Streiber et al. (1999). A reference in Powell (1992) to occurrence of Dracophyllum secundum R.Br. as occurring in the ‘Kendall district’ relates to D. macranthum and derives from collections made in 1929, which for many years were the only exemplars of this species.

 

3. D. macranthum resembles D. secundum R.Br., a widespread species in eastern New South Wales from the Rylstone and Wyong areas district south along the coast and coastal ranges to about the Budawang Range. The nearest recorded occurrence of D. secundum, in the Rylstone area, is separated from D. macranthum by a distance of about 250 km. Dracophyllum macranthum is readily distinguished from D. secundum, the latter having much smaller flowers (corolla tube 4-10 mm long) which open acropetally (basal flowers opening first). D. macranthum is unique in having basipetal flower opening, those at the apex of the inflorescence opening first, with sequential maturation down the inflorescence axis.

 

4. Dracophyllum macranthum E.A.Br. & N.Streiber occurs in a mountainous area about 20 km north-northeast of Taree, in the New South Wales North Coast Bioregion (sensu Thackway and Cresswell 1995). The species is known only from Coorabakh National Park and from closely adjacent small populations in Lansdowne State Forest and Comboyne State Forest. It occurs in the Local Government Areas of Greater Taree and possibly Port Macquarie-Hastings.

 

5. Dracophyllum macranthum E.A.Br. & N.Streiber occurs at elevations of 300 to about 500 m a.s.l., on loamy soils over a substrate of conglomerate rock, and possibly associated sandstones, of the Triassic Camden Haven Beds. D. macranthum is not known to occur on nearby emergent plugs of Tertiary rhyolite. Occurrences of the species extend about 8.5 km from north to south, and probably cover a range of less than 20 km2. Within this range the species occurs in localised colonies, which often tend to be distributed along linear landscape features including roadsides and steep rock drop-offs, and also on large sub-canopy conglomerate knolls. Colonies range in size from 3 to about 1000 plants, with ground areas of about 1 m2 to about 400 m2. The total area covered by known populations is probably less than 10,000 m2. Total population size has not been rigorously estimated but based on reconnaissance is likely to be 2500-5000 individuals (Makinson 2007). Approximately 30% of these plants are estimated to be fully mature individuals (Makinson 2007). The majority of collections have been on or close to road verges (especially cutting slopes), in part reflecting a lack of off-road survey, but possibly also reflecting a tendency for the species to take advantage of more open situations and drainage-gradient changes. A minority of sites (but perhaps accounting for a majority of individuals) are close to roads but not obviously influenced by them. No full targeted survey has yet been done; such survey is identified as a management strategy for this species in the Draft Management Plan for Coorabakh National Park (NSW NPWS 2002).

 

6. Dracophyllum macranthum occurs in three types of site, all tending to be on moderate to steep slopes, with often southerly aspects (occasionally north-easterly), and associated with gaps in a forest canopy, but never in fully open situations even if moist. The general habitat is moist eucalypt regrowth forest with canopy heights of 20-30 m, with Eucalyptus pilularis (Blackbutt) the dominant species at most sites, and a diverse shrubby understorey. The most common immediate habitat is in dense banks of fern (Gleichenia, usually also with Sticherus and assorted shrubs) on steep shady slopes and roadside cuttings, possibly associated with seepage areas. The second most common habitat, with probably the greatest number of individual plants, is on edges of roadside bluffs or over the entire tops of conglomerate outcrops, where these situations are beneath some degree of forest canopy; in these bluff-edge and outcrop situations there is little other associated vegetation, and very little soil, and the Dracophyllum may be dominant on the rock surface and at very high densities within a small area. The least common situation is in drier and more open understorey beneath Blackbutt or mixed eucalypt forest canopy with no ferns present; colonies in this situation usually number a few plants only, but the capacity of the species to occupy these drier sites may be critical to its ability to maintain gene flow and to recolonise areas after disturbance or on a seral basis.

 

7. No pollinators have been recorded for D. macranthum nor for other eastern Australian congeners; most literature references to pollinators in Dracophyllum are to New Zealand species where all are insect pollinated (mostly night-flying moths). The longevity of individual plants is unknown, but field observations (R. Makinson in litt., Oct. 2007) suggest that plants are likely to be fully mature at 3-5 years. The species probably does not have a resprouting capability after damage (R. Makinson in litt., Oct. 2007; C. Quinn, E. Brown, pers. comms. 2007). Benson & McDougall (1995) do not record any known instances of vegetative propagation in the closely related Dracophyllum secundum in the Sydney region. D. macranthum is currently assumed to be an obligate seeder. Seedling recruitment has been observed in larger populations (R. Makinson in litt., Oct. 2007, vouchered at NSW Herbarium).

 

8. Most or all members of the Ericaceae in Australia are thought to have obligate associations with mycorrhizal soil fungi (E. Brown, pers. comm. 2007). A study of the closely related Dracophyllum secundum (Allen et al. 1989) notes a root association with Ascomycete and Basidiomycete mycorrhizae that ‘may be seasonal’.

 

9. Inappropriate road maintenance activities potentially threaten some populations of this species, notwithstanding any possible microhabitat advantage they may get from road-associated aspect and drainage.

 

10. The southernmost known population, predominantly in Lansdowne State Forest, may be at risk from consequences of recent forestry operations a few tens of metres upslope of the very narrow roadside niche where the Dracophyllum occurs. Potential consequences include changed hydrology, introduction and/or provision of suitable colonisation sites for invasive weed species, changes to the local light and fire regimes, and possible introduction of soil- or water-borne pathogens.

 

11. Dracophyllum macranthum has not yet been tested for susceptibility to the soil pathogen Phytophthora cinnamomi, but a range of species and genera in the family Ericaceae are known to be susceptible (T. Suddaby in litt., Oct 2007). P. cinnamomi is commonly transported on cars and earth-moving equipment. Pending tests, P. cinnamomi should be considered as a potential threat, especially given the largely roadside nature of the known populations of D. macranthum, the dirt surface of the roads, the lack of made drains, the need for road maintenance in a fairly high-rainfall area, and the major soil disturbance upslope of the southernmost population. ‘Infection of native plants by Phytophthora cinnamomi’ is listed as a Key Threatening Process under the NSW Threatened Species Conservation Act 1995.

 

12. No major invasive weed problems have yet been noted at any sites at which Dracophyllum macranthum occurs, but establishment of certain weed species may constitute the most serious, immediate threat to the species. The weeds of concern are Crofton Weed (Ageratina adenophora), and Lantana (Lantana camara sens. lat.), both confirmed in late 2007 as present in Comboyne State Forest; the Draft Plan of Management for Coorabakh National Park (NSW NPWS 2002) notes the presence of both these weed species within the Park itself.

 

13. One Lantana infestation is within about 1 km to the north of the northernmost known population of Dracophyllum (R. Makinson in litt. Oct. 2007). Lantana does not favour the wetter fern-dominated sites in which much of the Dracophyllum occurs, but does favour the drier semi-open (often roadside) areas under broken canopy in which a minority of Dracophyllum plants occur. The Lantana population noted above is on the same conglomerate substrate and soil-type as the Dracophyllum. The modes of potential threat from Lantana may include changes to fire fuel load, suppression by shade and leaf mulching, potential allelopathy, and changes to soil microbiota (NSW Scientific Committee 2006). ‘Invasion, establishment and spread of Lantana (Lantana camara L. sens. lat)’ is listed as a Key Threatening Process under the NSW Threatened Species Conservation Act 1995.

 

14. A roadside infestation of Crofton Weed has been recorded (R. Makinson 2007) in Comboyne State Forest at a distance of no more than 3 km from the nearest (northernmost) population of Dracophyllum, and a little over 8 km from the southernmost population. The habitat preferences of Crofton Weed are outlined by Parsons & Cuthbertson (1992) as ‘Humid subtropics, principally in creek beds and forest clearings, in areas with steep (>20%) frost-free slopes where rainfall exceeds 1500 mm a year.’ These descriptors closely correspond with the general Dracophyllum habitat. Crofton Weed has a strong tendency to colonise specific sites conforming closely to the two microhabitats most favoured by the Dracophyllum: wet-seepage ledge/slope areas, and shady moist rock surfaces with a very shallow lithosol soil. The mode of potential threat from Crofton Weed is thus by direct invasion and displacement, and perhaps also by changes to soil microbiota. Crofton Weed is apomictic (Parsons and Cutherbertson 1992), highly fecund, has highly dispersible (wind-borne and water-borne) seeds, and the plants grow densely and form dense root-mats. Crofton Weed is a declared noxious plant under the Noxious Weeds Act 1993 in most coastal local government areas north of Gosford (Trounce and Dyason 2003).

 

15. Mist Flower (Ageratina riparia), a close congener of Crofton Weed, does not appear to be recorded for Coorabakh NP but is a similarly aggressive weed with broadly similar habitat requirements, widely naturalised along the NSW coast and coastal ranges. It is very under-collected and data are lacking on infestations in the area surrounding the range of Dracophyllum macranthum.

 

16. No data are available that would justify an inference of recent decline in numbers of Dracophyllum macranthum plants, or of its habitat. The whole range of the species appears to have been logged in the past and some disruption of populations may have occurred at that time, but the regrowth community includes a wide range of native species and very few weeds; past and current fragmentation of D. macranthum should not be assumed on current data.

 

17. All but two of the known populations of the species occur within Coorabakh National Park. Conservation of Dracophyllum macranthum is listed as a specific management objective in a Draft Management Plan for the Park (NSW NPWS 2002), and monitoring and surveys for the species are identified there as a management strategy.

 

18. Dracophyllum macranthum E.A.Br. & N.Streiber is not eligible to be listed as an endangered or critically endangered species.

 

19. Dracophyllum macranthum E.A.Br. & N.Streiber is eligible to be listed as a vulnerable species as, in the opinion of the Scientific Committee, it is facing a high risk of extinction in New South Wales in the medium-term future as determined in accordance with the following criteria as prescribed by the Threatened Species Conservation Regulation 2002:

 

Clause 17

The total number of mature individuals of the species is observed, estimated or inferred to be:

(c) low.

 

Clause 18

The geographic distribution of the species is observed, estimated or inferred to be very highly restricted such that it is prone to the effects of human activities or stochastic events within a very short time period.

 

 

Professor Lesley Hughes

Chairperson

Scientific Committee

Proposed Gazettal date: 04/07/08

Exhibition period: 04/07/08 – 29/08/08

 

References

 

Allen WK, Allaway WG, Cox GC, Valder PG (1989) Ultrastructure of mycorrhizas of Dracophyllum secundum R.Br. (Ericales: Epacridaceae). Australian Journal of Plant Physiology 16: 147-153.

 

Benson D, McDougall L (1995) Ecology of Sydney Plant Species Part 3: Dicotyledon families Cabombaceae to Eupomatiaceae. Cunninghamia 4(2): 217-431.

 

Brown EA, Streiber N (1999) Systematic studies in Dracophyllum (Epacridaceae) 2. New species of Dracophyllum in New South Wales. Telopea 8(3): 393-401.

 

Makinson RO (2007) Unpublished report on Dracophyllum macranthum to NSW Scientific Committee.

 

NSW NPWS (2002) Coorabakh National Park: Draft Plan of Management. NSW National Parks and Wildlife Service, Port Macquarie.

 

NSW Scientific Committee (2006) Lantana camara - key threatening process listing. Final determination. (DECC website www.nationalparks.nsw.gov.au/npws.nsf/Content/lantana_ktp, accessed 9 Nov. 2007).

 

Parsons WT, Cutherbertson EG (1992) Noxious weeds of Australia. Inkata Press, Melbourne & Sydney.

 

Powell JM (1992) Dracophyllum. In Harden JG (ed.), Flora of New South Wales vol. 3. New South Wales University Press, Kensington

 

Streiber N, Brown EA, Conn BJ, Quinn CJ (1999) Systematic studies in Dracophyllum (Epacridaceae) 1. Morphometric analyses of Dracophyllum secundum sensu lato. Telopea 8(3): 381-391.

 

Thackway R, Cresswell ID (1995) An interim biogeographic regionalisation for Australia. Version 4.0. (Australian Nature Conservation Agency: Canberra).

 

Trounce B, Dyason R (2003) Crofton Weed. Agfact P7.6.36, 2nd edition. NSW Department of Primary Industry. (www.dpi.nsw.gov.au/__data/assets/pdf_file/0010/155962/crofton-weed.pdf, accessed 5 Nov. 2007).

 

Page last updated: 28 February 2011