The Minister deleted this species from the vulnerable category, effective from 14 December 2013

Advice to the Minister for the Environment 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 on:

Hydrocharis dubia (frogbit)

2. Summary of Species Details

Taxonomy Conventionally accepted as Hydrocharis dubia (Blume) CA Backer. State Listing Status Listed as vulnerable under the Queensland Nature Conservation (Wildlife) Regulation 2006. This species is not listed in New South Wales. Description A monoecious, perennial aquatic that is either free-floating or rooted to the swamp bottom. Floating stolons produce clusters of leaves, peduncles and roots at their nodes. Leaves are broadly ovate, 2−7 cm long by 2−7 cm wide. Male and female flowers are white to pale yellow, erect and aerial, 8−15 mm long, with 3 sepals and 3 white petals. Fruit are 5−10 mm long, 4−8 mm wide, elliptic to circular with many spiny seeds (Aston, 1973; Cook and Lüönd, 1982; Stephens and Dowling, 2002; Jacobs, 2009). Distribution Known from two general areas: south-east Queensland to Kempsey, New South Wales; and northern Queensland from Townsville to Fletcher River (Charters Towers) (BRI collection records, n.d.). The Toomba population in north Queensland occurs in the Toomba Nature Reserve (BRI collection records, n.d.). The disjunct northern population in Queensland appears to have been established between 1973 and 1977 (BRI collection records, n.d.) indicating an increase in the range of this species. One herbarium label suggests that this species is a European import (BRI collection records, n.d.); although this cannot be ruled out, there is no supporting evidence. Globally, this species is found in an area bounded by India, Kashmir, Japan and Papua New Guinea (Aston, 1973; Cook and Lüönd, 1982). Relevant Details of the age of sexual maturity, life expectancy and natural Biology/Ecology mortality of this species are unknown. This species is perennial, possibly annual under certain conditions such as seasonal drying out (Cook and Lüönd, 1982). Flowers and fruits spring to autumn (Stephens and Dowling, 2002). Flowers are aerial and monoecious and morphology suggests insect pollination (Cook and Lüönd, 1982; Cronk and Fennessy, 2001). Aerial fruit bends down and becomes submerged, maturing underwater (Cronk and Fennessy, 2001; Stephens and Dowling, 2002). Occurs in shallow ponds or slow moving streams and in

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roadside lagoons, in mud or shallow water to 30 cm deep (Stephens and Dowling, 2002). Threats Known No known current threats. Potential Potential threats include hydrological changes, grazing and weed invasion (TSSC, 2008).

3. Public Consultation Notice of the proposed amendment was made available for public comment for 30 business days. No comments were received.

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 No data

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 Insufficient data – This species’ extent of occurrence in Queensland is approximately 15 000 km2 (5000 km2 in AND Brisbane and Logan River catchments in south-east Queensland, and 10 000 km2 in the Burdekin River catchment, north Queensland). Extent of occurrence in New South Wales is not known (BRI collection records, n.d.; Jacobs, 2009). Area of occupancy is unknown. Geographic distribution No – There are 12 known locations and although locations are precarious disjunct, within catchments this species is not fragmented and connectivity is not limited (Queensland Herbarium, 2009). The species has not been surveyed in Australia, and is likely to be more widespread in the catchments where it has been found (Queensland Herbarium, 2009).

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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 No data individuals AND Continued rate of decline No data OR Total no. of mature No data individuals AND Continued decline likely No data AND Geographic distribution No – see Criterion 2 precarious

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 No data individuals

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. Recommendations Based on available information on this species’ geographic distribution, which is not limited, and there are no known current threats, the Committee notes that this species does not meet any of the required criteria for listing in any category. (i) 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: Hydrocharis dubia

Threatened Species Scientific Committee 2 December 2010

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References cited in the advice Aston HI (1973). Aquatic of Australia. Melbourne University Press, Melbourne. Backer CA (1925). Handboek voor de Flora van Java. 1: 64. Drukkerijen Ruygrok and Company, Netherlands. BRI collection records (no date). Queensland Herbarium specimens. Cronk JK and Fennessy MS (2001). Wetland Plants, Biology and Ecology. Lewis Publishers, Washington DC. Cook CDK and Lüönd R (1982). A revision of the Hydrocharis (). Aquatic Botany 14: 177−204. Jacobs SWL (2009). Hydrocharis dubia. PlantNET – The Plant Information Network System of Botanic Gardens Trust (version 2.0). Sydney, NSW. Viewed: 16 July 2010 Available on the Internet at: http://plantnet.rbgsyd.nsw.gov.au/ Queensland Herbarium (2009). Information provided in Hydrocharis dubia Species Information Sheet. Report provided to the Department of Environment, Water, Heritage and the Arts (DEWHA). Stephens KM and Dowling RM (2002). Wetland Plants of Queensland, A Field Guide. CSIRO Publishing, Collingwood. Threatened Species Scientific Committee (TSSC) (2008). Conservation Advice for Hydrocharis dubia (frogbit). Department of the Environment, Water, Heritage and the Arts. Viewed: 17 May 2010 Available on the Internet at: http://www.environment.gov.au/biodiversity/threatened/species/pubs/3650-conservation- advice.pdf

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