Aponogeton queenslandicus (an aquatic plant) - endangered species listing

The Scientific Committee, established by the Threatened Species Conservation Act, has made a Final Determination to list the aquatic plant Aponogeton queenslandicus H. Bruggen as an ENDANGERED species on Part 1 of Schedule 1 of the Threatened Species Conservation Act. Listing of endangered species is provided for by Part 2 of the Act.

NSW Scientific Committee - final determination

The Scientific Committee has found that:

1. Aponogeton queenslandicus (Aponogetonaceae) was first described in 1969.

2. The following description is taken from Hellquist and Jacobs (1998), Aponogetonaceae of Australia, with description of six new taxa. Telopea 8(1) 7-19. "Rooted, submerged and floating, perennial aquatic. Tubers 1-5 cm long, 1.8-2.6 cm wide, extremely strigose. Leaves submersed and floating; submersed blades uncommon, elliptic to lanceolate, green, 10-13(-70) cm long, 2.9-4.5 cm wide; margins flat; base obtuse, attenuate, or truncate; apex obtuse; 7-9 veined; 0-1 row of lacunae on each side of midvein; petiole to 15 cm long. Floating leaves ovate or elliptic, 2.8-14(-27) cm long, 0.6-4.3 cm wide; light green to green, base mostly cordate, rarely truncate or cuneate; apex obtuse, mucronulate, acuminate, rarely emarginate; 7-9 veined; petiole to 66 cm long. Peduncle to 30(-73) cm long; 1.8-2.5 mm wide at base often only slightly broadening or to 2-4.5 mm wide at base of inflorescence. Spathe to 1.5 cm long, caducous. Inflorescence yellow, emergent or floating, single, usually tightly-flowered; rachis 15-27(-45) mm wide. Flowers turned in all directions. Perianth segments 2, spathulate, 1-veined, 1.4-2 mm long, 0.5-1 mm wide. Stamens 6, up to 3 mm long, slightly broader at base. Carpels (2-)3(-4). Infructescence dense. Fruit 2.5-4.5 mm long, 2.3-3 mm wide, with a terminal, often curved, beak. Seeds narrowly elliptic, 4-13 per fruit, 1.7-3 mm long, 0.6-1 mm wide, with a double testa; outer testa loose, transparent and reticulate, inner testa brown and close fitting; plumule absent."

3. The species occurs in Queensland, the Northern Territory and in far western NSW. In NSW it is currently only known from a single small wetland in Nocoleche Nature Reserve. Despite searches in and around Nocoleche Nature Reserve, no other locations have been found.

4. In Nocoleche, Aponogeton queenslandicus occurs in an ephemeral swamp of lignum (Muehlenbeckia florulenta) with fringing Eucalyptus ochrophloia (yapunyah) and E. largiflorens (blackbox) trees, on the edge of the Paroo River floodplain. The substrate is heavy grey clay.

5. Threats to the species involve changes to the flooding regime of the Paroo River and associated floodplain, including changes to the flood size, frequency and duration. Reduced flooding (extent and duration) will alienate habitat and affect plant recruitment. Increased salinity levels caused by floodplain clearing and irrigation are also a potential threat. Due to the small population size and extent the species is susceptible to catastrophic events and localised extinction.

6. In view of 3, 4 & 5 above the Scientific Committee is of the opinion that the species is likely to become extinct in nature in NSW unless the circumstances and factors threatening its survival or evolutionary development cease to operate.

Proposed Gazettal date: 24/11/00