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Listing Statement for trichomanes subsp. trichomanes (dolerite spleenwort) Asplenium trichomanes subsp . trichomanes

dolerite spleenwort

T A S M A N I A N T H R E A T E N E D S P E C I E S L I S T I N G S T A T E M E N T

Image by R. Schahinger

Scientific name: Asplenium trichomanes L., Sp. Pl. 2: 1080 (1753) subsp. trichomanes Common name: dolerite spleenwort (Wapstra et al . 2005) Group: vascular , pteridophyte, family

Status: Threatened Species Protection Act 1995 : vulnerable Environment Protection and Biodiversity Conservation Act 1999 : Not listed

Distribution: Endemic status: Not endemic to Tasmanian NRM Region: North

Figure 1 . Distribution of Asplenium trichomanes subsp. Plate 1. Asplenium trichomanes subsp. trichomanes trichomanes in Tasmania (Image by R. Schahinger)

1 Threatened Species Section – Department of Primary Industries, Parks, Water and Environment

Listing Statement for Asplenium trichomanes subsp. trichomanes (dolerite spleenwort)

IDENTIFICATION AND ECOLOGY Asplenium trichomanes subsp. trichomanes (Duncan Asplenium trichomanes subsp. trichomanes is a & Isaac 1986). with clusters of 5 to 25 cm long fronds arising from a short, thick rhizome. The small pinnae DISTRIBUTION AND HABITAT curl under in dry times though the fern quickly Asplenium trichomanes subsp. trichomanes occurs in recovers when moisture becomes available. Tasmania, Victoria and New South Wales When fertile, ripe sporangia can cover the lower (where it is rare), and is also known from surface of the pinnae (Duncan & Isaac 1986). , Asia, Europe and The fern can resprout from its thick rhizome (Garrett 1997). following fire or other damage. Asplenium trichomanes subsp. trichomanes can be identified Within Tasmania, Asplenium trichomanes subsp. year round. trichomanes has been recorded from three sites in the northeast: Mt Durham, Huntsmans Cap, Description and Valley Road on the northern flanks of the Asplenium trichomanes subsp. trichomanes arises Fingal Tier (Figure 1; Garrett 1995, 1996 & from a short, thick rhizome covered with very 1997). The linear extent of the sites is about 13 dark, shiny, coarse, lattice-like scales. Fronds km, the extent of occurrence 7 to 8 km 2, and are clustered, erect and 5 to 25 cm long. The the area of occupancy approximately 1 ha. stipe is short, brittle, shiny, black and flattened above, with a tuft of scales at its base. The Asplenium trichomanes subsp. trichomanes occurs lamina is deep green, linear, pinnate and firm in on exposed dolerite outcrops in dry sclerophyll texture. The rachis is shiny, blackish, brittle and forest in areas of low rainfall between 450 and grooved with narrow, fragmented wings. There 680 m above sea level (Garrett 1997). are 15 to 40 pairs of shortly stalked pinnae grow on northwest to northeast facing outcrops arranged asymmetrically. The pinnae are oblong in the shallow soil of crevices (Plate 2) or to oval, 4 to 10 mm long with deeply crenate to sloping rock platforms. Co-occurring may almost entire margins. The veins are obscure include the xerophytes Cheilanthes austrotenuifolia , but minor veins branch pinnately from the Pleurosorus rutifolius and Pellaea calidirupium midvein. After 6 to 12 months, the lower (Garrett 1995). pinnae are often deciduous leaving small projections. Sori on the undersurface of pinnae POPULATION ESTIMATE are arranged in 3 to 6 pairs along the minor Approximately 230 plants have been recorded veins, oblique to the midvein. Each sorus is in total, with the majority of plants in the Mt protected by a pale, thin indusium with an Durham subpopulation which is composed of 2 irregular margin, opening towards the centre of sites (Table 1). Likely sites for Asplenium the pinna. trichomanes subsp. trichomanes were identified in [description from Duncan & Isaac (1986)] 1995 (Garrett 1995) and targeted surveys conducted in 1996 for the 1997 Regional Forest Confusing species Agreement (RFA). No new sites have been This taxon is quite distinctive and is easily identified since, despite the taxon having some distinguished from Asplenium trichomanes subsp. priority given its status as an RFA priority quadrivalens in that the pinnae are quite widely species and searches by fern enthusiasts. The spaced, rounded and scarcely longer than they likelihood of sufficient new subpopulations or are wide. Asplenium trichomanes subsp. numbers of mature individuals being quadrivalens is usually associated with limestone discovered to not allow the taxon to meet the whereas Asplenium trichomanes subsp. trichomanes criteria for vulnerable is considered low. occurs on non-calcareous rock, in Tasmania, always dolerite. Asplenium trichomanes subsp. RESERVATION STATUS quadrivalens has twice as many chromosomes as The taxon is reserved in Huntsmans Cap Forest Reserve. 2 Threatened Species Section – Department of Primary Industries, Parks, Water and Environment

Listing Statement for Asplenium trichomanes subsp. trichomanes (dolerite spleenwort)

Table 1. Population summary for Asplenium trichomanes subsp. trichomanes in Tasmania

Subpopulation Tenure NRM 1:25 000 Year last Area of Number of region * mapsheet & (first)seen occupancy mature plants (ha) 1 Mt Durham State Forest North St Marys 2005 139** & 46** (upper & lower) (1989) 2 Valley Road State Forest North St Marys 2005 14** (1992) 6# 3 Huntsmans Cap Huntsmans Cap North Dublin 1996 30** Forest Reserve Town (1996) * NRM region = Natural Resource Management region; ** Garrett (1997); # Threatened Species Section surveys

THREATS, LIMITING FACTORS & MANAGEMENT ISSUES Threats to Asplenium trichomanes subsp. trichomanes include: • exposure to drying from operations such as quarrying and inappropriate timber harvesting techniques; • competition from pine wildlings; • an inappropriate fire regime; Plate 2. Rock crevice habitat Asplenium trichomanes • stochastic risk of extinction. subsp. trichomanes (Image by R. Schahinger) The Valley Road subpopulation occurs on State Forest near the face of a disused quarry. Garrett CONSERVATION STATUS (1997) noted an apparent decline in numbers at Asplenium trichomanes subsp. trichomanes was listed this site since its discovery in 1992, attributing as vulnerable on the Tasmanian Threatened the decline to quarrying operations possibly Species Protection Act 1995 in 2009, meeting the over-exposing the site, with plants being lost following criterion: during periods of subsequent drought (a view supported by Threatened Species Section D. total population very small or area of surveys in 2005). A renewal of quarrying could occupancy restricted, and; have a further impact on the taxon. 1. total population estimated to number fewer than 1,000 mature individuals; The Mt Durham subpopulation also occurs on State Forest, with the base of the rock outcrop 2. total population with an area of occupancy that supports the lower subpopulation being less than 0.05 km 2 (5 hectares), and typically only 10 to 20 m from the boundary road of a in five or fewer locations that provide an mature Pinus radiata plantation. Garrett (1997) uncertain future due to the effects of human considered that the habitat of the taxon had not activities or stochastic events, and thus suffered as a result of nearby clearance during capable of becoming endangered within a the plantation’s establishment or from shading very short time. by the pines, though he did recommend that Asplenium trichomanes subsp. trichomanes was due care be taken during any future harvesting identified as an RFA priority species in 1997. operations. However, surveys by Threatened Species Section personnel in 2005 revealed that a number of pine wildlings had established

3 Threatened Species Section – Department of Primary Industries, Parks, Water and Environment

Listing Statement for Asplenium trichomanes subsp. trichomanes (dolerite spleenwort) themselves in areas of potential habitat for the • monitor known sites at least once every 3 to taxon (Schahinger, pers. comm.). These pose an 5 years to determine population trend and ongoing threat to the taxon if not removed. whether management intervention is Frequent fire has the potential to impact required; adversely upon Asplenium trichomanes subsp. • identify and survey potential habitat; trichomanes, though this is considered to be a • provide information and extension support relatively low risk due to the fire-protected to the Northern Natural Resource nature of its rocky habitat and the ability of the Management committee, local councils, taxon to resprout from its thick rhizome. government agencies and the local The localised nature of the Asplenium trichomanes community on the locality, significance and subsp. trichomanes subpopulations also exposes management of known subpopulations and them to the risk of extinction through potential habitat. stochastic events. BIBLIOGRAPHY MANAGEMENT STRATEGY Duncan, B.D. & Isaac, G. (1986). Ferns and Allied Plants of Victoria, Tasmania and South What has been done? Australia. Melbourne University Press, Potential sites for the taxon were identified and Carlton, Victoria. surveyed for the Regional Forest Agreement 1997 . Garrett, M. (1995). Distribution and ecology of Some sites were visited during surveys in 2005 ferns on dry rock outcrops in Tasmania, by personnel with the Threatened Species with special reference to Fingal Tier. Section (see Table 1). Tasforests 7: 77–92. Garrett, M. (1996). The Ferns of Tasmania. Their Management objectives ecology and distribution . Tasmanian Forest • prevent the loss of known subpopulations; Research Council Inc., Hobart. • prevent the loss or degradation of potential Garrett, M. (1997). Rare or Threatened Tasmanian habitat; Forest Ferns . Report to the Tasmanian RFA Environment and Heritage Technical • find new subpopulations. Committee, Tasmanian Public Land Use Commission, Hobart. What is needed? Orr, S. & Gerrand, A.M. (1998). Management • include known sites on State Forest in Decision Classification: A system for zoning Special Management Zones (Orr & land managed by Forestry Tasmania. Gerrand 1998); Tasforests 10: 1–14. • remove pine wildings from known sites and RFA (1997). Tasmanian Regional Forest Agreement . their vicinity; Commonwealth of Australia and the State of • should forestry operations (including Tasmania. quarrying) be proposed within 5 km of Wapstra, H., Wapstra, A., Wapstra, M. & known sites, survey for the taxon in Gilfedder, L. (2005). The Little Book of potential habitat that may be impacted, in Common Names for Tasmanian Plants . order to prevent impacts to presently Department of Primary Industries, Water undetected sites; and Environment, Hobart. • avoid burning habitat in the vicinity of known sites if burnt less than 15 to 25 years earlier; • as a priority, resurvey the Huntsmans Cap subpopulation;

4 Threatened Species Section – Department of Primary Industries, Parks, Water and Environment

Listing Statement for Asplenium trichomanes subsp. trichomanes (dolerite spleenwort)

Prepared in June 2009 under the provisions of the Tasmanian Threatened Species Protection Act 1995. Approved by the Secretary and published in February 2010.

Cite as: Threatened Species Section (2010). Listing Statement for Asplenium trichomanes subsp . trichomanes (dolerite spleenwort). Department of Primary Industries, Parks, Water and Environment, Tasmania.

View: www.dpipwe.tas.gov.au/threatenedspecieslists Contact details: Threatened Species Section, Department of Primary Industries, Parks, Water and Environment, Tasmania, Australia, 7001. Phone (03) 6233 6556; fax (03) 6233 3477. Permit: It is an offence to collect, disturb, damage or destroy this species unless under permit.

5 Threatened Species Section – Department of Primary Industries, Parks, Water and Environment