Listing Statement for aurantiaca (orangetip fingers) Caladenia aurantiaca

orangetip fingers

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 Gail Pollard

Scientific name: Caladenia aurantiaca (R.S.Rogers) Rupp, Proc. Linn. Soc. N.S.W. 71: 280 (1947) Common name: orangetip fingers (Wapstra et al. 2005) Group: vascular , , family Name history: Petalochilus aurantiacus Status: Threatened Species Protection Act 1995: endangered Environment Protection and Biodiversity Conservation Act 1999: Not listed Distribution: Endemic status: Not endemic to Tasmanian NRM Region: North

Figure 1. Distribution of Caladenia aurantiaca within Plate 1. Caladenia aurantiaca from Deal Tasmania, showing NRM regions (image by Gail Pollard)

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

Listing Statement for Caladenia aurantiaca (orangetip fingers)

IDENTIFICATION AND ECOLOGY The response of species of Caladenia to fire Caladenia aurantiaca belongs to one of the small- varies but most species respond vigorously to flowered sections of the genus Caladenia, high intensity fires during the preceding sometimes included in the genus Petalochilus summer (Jones et al. 1999). The precise (Jones et al. 2001). This group of Caladenia response of Caladenia aurantiaca to fire is species is distinguished morphologically from unknown but its habitat is generally considered other sections by the labellum calli being to be fire-prone. separate from each other (not on a plate-like structure) and usually arranged in two rows. Description The heads of individual calli are enlarged and are 5 to 17 cm tall. The scape is very the basal calli are larger than and usually of a thin, wiry, and sparsely hairy. The leaf is erect different colour to the other labellum calli. The and narrowly linear, and is 4 to 8 cm long and 2 labellum and are usually ornamented mm wide. The is 1 or 2 flowered, with prominent red transverse bars, although with the flowers being short-lasting (only 2 to 4 these are absent in Caladenia aurantiaca (Jones et days before self-pollinating). Flowers are 15 to al. 2001). 20 mm across. The flowers are white internally, Plants grow singly or in loose groups. greenish externally lacking any other coloration. Flowering plants usually have a single narrow The labellum is white with a bright orange mid- hairy dark green basal leaf, a thin wiry hairy lobe, and orange calli. The dorsal (upper) flower stem and 1 to 5 flowers that are usually is oblong, erect to incurved (closely hooding white or pink. The perianth segments are all of the column), and 7 to 10 mm long and 2 mm a similar size although the dorsal sepal can be wide. The lateral (lowermost) are shorter in some species. The dorsal sepal is narrowly lanceolate, parallel and obliquely erect or recurved away from the column and deflexed, and 7 to 10 mm long and 2.5 mm labellum. The lateral sepals and project wide. The petals are narrowly lanceolate, forward or spread like the fingers of a hand. spreading or obliquely deflexed, and 7 to 10 The labellum is hinged and 3-lobed with erect mm long and 2 mm wide. The labellum is lateral lobes and a projecting or recurved mid- broadly ovate, and 4.5 to 5 mm long and 5 to lobe that is ornamented with short marginal 5.5 mm wide. The lateral lobes are erect and teeth. The calli are stalked and clubbed, often embrace the column, and have entire or slightly with yellow to orange heads and usually irregular margins. The mid-lobe is triangular arranged on two rows, sometimes four in some and recurved, with 1 to 3 pairs of short, broad, species (Jones 2006). orange marginal calli. The lamina calli are in 2 rows and extend to the base of the mid-lobe. All Caladenia species are and die back The column is pale green, and 4.5 to 5 mm long after flowering to small subterranean tubers and 2 mm wide. enclosed by a fibrous sheath or tunic. The basal leaf appears above ground in late autumn or [description from Jones 1998, Jones et al. 1999, early winter following rains. The larger- Jones 2006] flowered species in the Petalochilus group of Confusing species species are pollinated by small native bees and the smaller-flowers species are mostly self- Caladenia aurantiaca is a member of the Caladenia pollinating, sometimes without opening (Jones carnea complex (Jones et al. 1999) but is 2006). Caladenia aurantiaca is one of the smaller- distinctive and easily recognised because of its flowered species and has short-lived flowers distinctive white flowers with bright orange that are self-pollinating (Jones et al. 1999). labellum tip and calli. It is somewhat similar to Caladenia alata and white-flowered forms of the On mainland , the flowering period of Caladenia carnea species-complex but a Caladenia aurantiaca is August to November but combination of characters make identification the Tasmanian collections are from early to mid relatively simple. October and early November (Wapstra et al. 2008). 2 Threatened Species Section – Department of Primary Industries, Parks, Water and Environment

Listing Statement for Caladenia aurantiaca (orangetip fingers)

DISTRIBUTION AND HABITAT It is probable that the subpopulations of Caladenia aurantiaca occurs in and Caladenia aurantiaca on the eastern Tasmania (Jones et al. 1999). Within Tasmania represent the southern limit of the the species is known from a small number of species’ distribution and that it was never sites on in eastern Bass Strait widespread and/or common in the Furneaux (Figure 1). Group. On mainland Australia Caladenia aurantiaca POPULATION ESTIMATE occurs in well-drained peaty sand and sandy The total population of Caladenia aurantiaca is loams in heathland, heathy forest and coastal probably less than 250 mature individuals as all scrub at elevations below 80 m (Jones 1998, sites are represented by very low numbers Jones 2006). On Deal Island Caladenia aurantiaca (Table 1). occurs in Allocasuarina verticillata forest, sometimes on the edge of Eucalyptus nitida Although it is possible that more woodland, with a Poa labillardierei and light subpopulations of Caladenia aurantiaca exist, Pteridium esculentum understorey (Plate 2). given its apparent specific habitat requirements, Elevation varies from around 100 to 150 m. the attention its broader potential habitat has received in terms of targeted survey effort (e.g. by naturalists on the Bass Strait islands), and the distinctiveness of the species, detection of further subpopulations is likely to be a chance event. For example, while the botany of Deal Island and nearby islands has been described (e.g. Harris & Davis 1995, Kirkpatrick 1995), large parts of the islands remain unexplored botanically and additional localised subpopulations of several threatened species are likely to be serendipitously discovered. However, it seems unlikely that subpopulations of Caladenia aurantiaca large enough to influence its conservation status will be discovered in the Plate 2. Habitat of Caladenia aurantiaca on Deal future. Island (image by Gail and John Pollard)

Table 1. Population summary for Caladenia aurantiaca in Tasmania

Subpopulation Tenure NRM 1:25000 Year last Area Number Region * Mapsheet seen occupied of mature (ha) plants 1 Deal Island North Deal Island 1992 unknown 31 (gully northwest of National Park highest eastern peak) 2 Deal Island Kent Group North Deal Island 2004 0.0001 c. 20 (base of Mount Fugi) National Park 3 Deal Island Kent Group North Deal Island 2008 0.0001 c. 20 (‘Peg Leg Saddle’) National Park * NRM region = Natural Resource Management region

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

Listing Statement for Caladenia aurantiaca (orangetip fingers)

RESERVATION STATUS threatened species, also has the potential to Caladenia aurantiaca occurs in Kent Group deleteriously affect localised subpopulations of National Park. delicate herbs. One subpopulation of Caladenia aurantiaca (Peg Leg Saddle) is already close to an CONSERVATION ASSESSMENT occurrence of ragwort (Senecio jacobaea). Caladenia aurantiaca was listed as rare on the Inappropriate disturbance regime: The schedules of the Tasmanian Threatened Species subpopulations on Deal Island are relatively Protection Act 1995 in 1995 and uplisted to secure from inadvertent disturbance. However, endangered in 2001. It meets criterion D for grazing pressure on the island is very high from endangered: total population estimated to species such as rabbits, possums and wallabies number fewer than 250 mature individuals. and invertebrates such as snails. The impact of this disturbance on subpopulations of Caladenia THREATS, LIMITING FACTORS AND aurantiaca is unknown. MANAGEMENT ISSUES Climate change: Changes in the rainfall Caladenia aurantiaca occurs in highly localised pattern may lead to the habitat becoming sites. Because of its localised distribution, unsuitable for the species and associated stochastic events can lead to extinction. In pollinators and mycorrhizal fungi. addition, the small size of subpopulations may Stochastic events: While stochastic events are lead to inbreeding problems possibly in by definition unpredictable, in this case, such combination with insufficient maintenance of events are most likely to be associated with populations of pollinating insects and events such as unintended fires (e.g. arson, associated mycorrhizal fungi. lightning strikes). The sites supporting Caladenia Inappropriate fire regime: The ecological aurantiaca are infrequently visited by people and requirements of Caladenia aurantiaca, especially deliberate or inadvertent (e.g. for the purpose in relation to the frequency, timing and of identification) picking of flowers is a low, intensity of fires, is largely unknown but it may but genuine, risk to a species with low be adversely affected by frequent high intensity population numbers at highly localised sites. fires that affect the litter and soil conditions. MANAGEMENT STRATEGY Known sites are subject to infrequent wildfires (usually deliberately lit). Fire management on What has been done? the eastern Bass Strait islands known to support Caladenia aurantiaca (or potential habitat No sites within gazetted reserves are actively elsewhere on other islands) is likely to be managed to maintain and/or enhance the focused on preventing widespread wildfires. habitat for the species. There is a management The potential impact of controlled burns (e.g. plan for but it does autumn fuel reduction burns), should they be not make any specific recommendations on undertaken, on subpopulations of Caladenia relation to Caladenia aurantiaca (Parks & Wildlife aurantiaca is unknown. The combination of fire Service 2005). events and other risk factors (e.g. increased Caladenia aurantiaca is included in the Flora grazing pressure and weed invasion after fire) Recovery Plan: Threatened Tasmanian Orchids 2006– probably presents a greater risk than the actual 2010 (Threatened Species Section 2006). fire event itself. Weed invasion: Deal Island has several Management objectives locations supporting potentially invasive weeds (Parks & Wildlife Service 2005) and these have What is needed? the potential to spread to sites supporting The main objective for the management of Caladenia aurantiaca. In the first instance, weeds Caladenia aurantiaca is to ensure that there is no may out-compete more delicate orchids and decline in the known subpopulations. locally eliminate subpopulations. However, weed management activities, if undertaken The following general guidelines may improve without taking into account the presence of the opportunities for detecting further 4 Threatened Species Section – Department of Primary Industries, Parks, Water and Environment

Listing Statement for Caladenia aurantiaca (orangetip fingers) subpopulations: Threatened Species Unit (2006). Flora Recovery Plan: Threatened Tasmanian Orchids 2006–2010. • undertake additional surveys of the Department of Primary Industries and subpopulations on Deal Island to determine Water, Hobart. their precise extent and condition. Such information is important to developing an Wapstra, H., Wapstra, A., Wapstra, M. & appropriate management strategy for each Gilfedder, L. (2005). The Little Book of of the sites. These surveys could be Common Names for Tasmanian Plants. undertaken by volunteer lighthouse Department of Primary Industries, Water keepers; and Environment, Hobart. Wapstra, M., Roberts, N., Wapstra, H. & • undertake surveys for the species in Wapstra, A. (2008). Flowering Times of potential habitat in the Tasmanian Orchids: A Practical Guide for Field during the predicted flowering period (early Botanists. Self-published by the authors (April October to early November; 2008 version). • incorporate the management requirements of Caladenia aurantiaca into updated Prepared under the provisions of the management plans for Kent Group Tasmanian Threatened Species Protection Act 1995. National Park and any associated action Approved by the Secretary and published in plans such as fire and weed management May 2013. plans. Cite as: Threatened Species Section (2013). Listing Statement for Caladenia aurantiaca BIBLIOGRAPHY (orangetip fingers). Department of Primary Harris, S. & Davis, G. (1995). The vegetation Industries, Parks, Water and Environment, and flora of Deal Island, Kent Group. Papers Tasmania. and Proceedings of the Royal Society of Tasmania View: 129: 43–51. www.dpipwe.tas.gov.au/threatenedspecieslists Jones, D.L. (1998). A taxonomic review of Contact details: Threatened Species Section, Caladenia in Tasmania. Australian Orchid Department of Primary Industries, Parks, Research 3: 16–60. Water and Environment, GPO Box 44, Hobart, Jones, D. (2006). A Complete Guide to Native Tasmania, Australia, 7001. Ph (03) 6233 6556; Orchids of Australia including the Island fax (03) 6233 3477. Territories. New Holland Publishers Permit: It is an offence to collect, disturb, (Australia), Sydney. damage or destroy this species unless under Jones, D., Wapstra, H., Tonelli, P. & Harris, S. permit. (1999). The Orchids of Tasmania. Melbourne University Press, Carlton South, Victoria. Jones, D.L., Clements, M.A., Sharma, I.K. & Mackenzie, A.M. (2001). A new classification of Caladenia R.Br. (Orchidaceae). The Orchadian 13(9): 389–419. Kirkpatrick, J.B. (1995). The vegetation of Dover and Erith Islands, Kent Group, Bass Strait. Papers and Proceedings of the Royal Society of Tasmania 129: 25–330. Parks and Wildlife Service (2005). Kent Group National Park (Terrestrial Portion) Management Plan 2005. Parks and Wildlife Service, Department of Tourism, Parks, Heritage and the Arts, Hobart.

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