The Minister deleted this species from the vulnerable category, effective from 6 March 2013.

Advice to the Minister for Sustainability, Environment, Water, Population and Communities from the Threatened Species Scientific Committee (the Committee) on Amendment to the list of Threatened Species under the Environment Protection and Biodiversity Conservation Act 1999 (EPBC Act)

1. Reason for Conservation Assessment by the Committee This advice follows assessment of new information provided through the Species Information Partnership with Western on: Stylidium merrallii (Merrall’s triggerplant)

2. Summary of Species Details Conventionally accepted as Stylidium merrallii (F.Muell.) T.Durand and B.D.Jackson State Listing Status Listed as Declared Rare Flora that is rare or likely to become extinct under the Western Australian Wildlife Conservation Act 1950. Managed as vulnerable by the Western Australian Government. Description A rhizomatous, rosette perennial with several slender, erect or spreading stems that may be up to 18 cm long, arising from the basal rosette. There are three types of leaves. One type is up to 2 cm long, crowded on the basal rosette, firm and flat with a white margin and possesses minute teeth. The second type is scattered along the stem, lacks a white margin and is also up to 2 cm in length. The third type is floral leaf, arranged along the length of the flowering stem. Flowers are pink (rarely white) with dark markings near the throat (Brown et al., 1998; DEC, 2009). Adventitious rosettes develop in the leaf axils late in the flowering period. On contact with the ground, the rosettes develop roots and new develop. This produces many young rosettes radiating out from the parent (Brown et al., 1998). Distribution Endemic to and known from six populations in the Kellerberrin–Mt Marshall area of the eastern wheatbelt region. Three populations occur within nature reserves. Seed collected from one population in 2003 is stored in the Department of Environment and Conservation’s Threatened Flora Seed Centre. The species is cultivated at Kings Park and Botanic Gardens, (DEC, 2009). Relevant Restricted to growing on sandy loam in drainage channels and Biology/Ecology seasonally inundated flats, on the aprons of granite rock outcrops (Brown et al., 1998). Flowering occurs from October to February, but is largely dependent on available soil moisture (Brown et al., 1998; DEC, 2009). Cultivated specimens flower into May (Kenneally and Lowrie, 1994). Details of the ages of sexual maturity, life expectancy and natural mortality of this species are unknown.

Stylidium merrallii (Merrall’s trigger plant) Listing Advice Page 1 of 4 The Minister deleted this species from the vulnerable category, effective from 6 March 2013.

Threats Known Road, track and drain maintenance activities are known threats for one population which occurs within a spoon drain where maintenance activities are likely to impact on the species. Past evidence suggests one population has been graded and an access track goes through the middle of another population. Plants of Merrall’s triggerplant first collected from one population were found to be infected with the rust fungus, Punninia stylidii. There have been no further records of the disease (DEC, 2009). Grazing was noted at one population but was suspected to be by native animals rather than stock; this population is now fenced from stock (DEC, 2009) Potential Potential threats to this species include recreational activities and weed invasion. Illegal campfires have been noted in close proximity to one population. Weed invasion is a potential threat to three populations. Weeds suppress early plant growth by competing for soil moisture, nutrients and light. They also exacerbate grazing pressure and increase the fire hazard due to the easy ignition of high fuel loads, which are produced annually by many weed species (DEC, 2009).

3. Public Consultation Notice of the proposed amendment was made available for public comment for 30 business days. Any comments received that are relevant to the survival of the species have been considered by the Committee.

4. How judged by the Committee in relation to the EPBC Act criteria and Regulations

Criterion 1: It has undergone, is suspected to have undergone or is likely to undergo in the immediate future a very severe, severe or substantial reduction in numbers Not eligible Criterion element Evidence Reduction in numbers Not substantial − The number of known plants has increased from 76 000 plants in 1994 to 103 000 plants in 2008 (DEC, 2009) due to an increase in the number of populations located. New populations were located in 2000 and 2005 and future surveys proposed (by DEC) at known populations where nearby drainage lines may provide further plants (DEC, 2009). Therefore the number of known individuals may increase if new populations are found.

Stylidium merrallii (Merrall’s trigger plant) Listing Advice Page 2 of 4 The Minister deleted this species from the vulnerable category, effective from 6 March 2013.

Criterion 2: Its geographic distribution is precarious for the survival of the species and is very restricted, restricted or limited Not eligible Criterion element Evidence Geographic distribution Limited − Extent of occurrence is 10 000 km2 and the area of occupancy is unknown (DEC, 2009). AND

Geographic distribution No − Whilst the species occurs within discontinuous habitat precarious over six populations and therefore has a fragmented distribution, current and potential threats are being managed by DEC and three of the populations are within conservation estates (DEC, 2009). The number of Merrall’s triggerplants has increased from approximately 76 000 plants in 1994 to approximately 103 000 plants in 2008 (DEC, 2009) due to the increased number of populations located.

Criterion 3: The estimated total number of mature individuals is very low, low or limited; and either (a) evidence suggests that the number will continue to decline at a very high, high or substantial rate; or (b) the number is likely to continue to decline and its geographic distribution is precarious for its survival Not eligible Criterion element Evidence Total no. of mature Not limited – In 2008 Merrall’s triggerplant had a population of individuals approximately 103 000 plants (DEC, 2009). Although the number of mature individuals was not recorded, given the large AND total population size, the Committee judges that they are not limited. Continued rate of decline No – see Criterion 1 OR Total no. of mature No – in 2008 Merrall’s triggerplant had a population of individuals approximately 103 000 plants (DEC, 2009). Although the number of mature individuals was not recorded, given the large AND total population size, the Committee judges that they are not limited. Continued decline likely No – see Criterion 1 AND Geographic distribution No – see Criterion 2 precarious

Stylidium merrallii (Merrall’s trigger plant) Listing Advice Page 3 of 4 The Minister deleted this species from the vulnerable category, effective from 6 March 2013.

Criterion 4: The estimated total number of mature individuals is extremely low, very low or low Not eligible Criterion element Evidence Total no. of mature Insufficient data − Whilst the number of mature individuals is individuals not known, in 2008 Merrall’s triggerplant had a population of approximately 103 000 plants (DEC, 2009). Therefore the number of mature individuals is unlikely to be low.

Criterion 5: Probability of extinction in the wild that is at least (a) 50% in the immediate future; or (b) 20% in the near future; or (c) 10% in the medium-term future Not eligible Criterion element Evidence Probability of extinction in No data the wild

5. Recommendation The Committee notes that this species is eligible for delisting due to the availability of more information on increased numbers of populations and individual plants and low significance of threats.

The Committee recommends that the list referred to in section 178 of the EPBC Act be amended by deleting from the list in the vulnerable category: Stylidium merrallii

Threatened Species Scientific Committee 26 August 2010

References cited in the advice Brown A, Thomson-Dans C and Marchant N (eds) (1998). Western Australia’s threatened flora, Department of Conservation and Land Management, Western Australia. Department of Environment and Conservation (DEC) (2009). Records held in DEC’s declared flora database and rare flora files. Western Australian Department of Environment and Conservation, Western Australia. Kenneally DV and Lowrie A (1994). Rediscovery of the presumed extinct trigger plant Stylidium merrallii () with an amended description of the species and its’ conservation status. Western Australian Naturalist. 19(4): 269−277.

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