Zannichellia palustris (a submerged aquatic plant) - endangered species listing

The Scientific Committee, established by the Threatened Species Conservation Act, has made a Final Determination to list the submerged aquatic plant Zannichellia palustris L. (Zannichelliaceae) as an ENDANGERED SPECIES on Schedule 1 Part 1 of the Act. Listing of endangered species is provided for by Division 2 Part 2 of the Act.

NSW Scientific Committee - final determination

The Scientific Committee has found that:

1. Zannichellia palustris L. is a submerged monoecious weakly rhizomatous aquatic annual or perennial plant. [Described on p.29 - 30 of Harden, G. (ed.) 1993 Flora of New South Wales Vol.4 NSW University Press, Sydney.]

2. Zannichellia palustris has a cosmopolitan distribution, but in Australia is known only from the Murray River estuary in South Australia and the lower Hunter region in NSW. It is considered to be indigenous in NSW and is recognized as rare nationally [Briggs, J.D. and Leigh, J.H. 1995 Rare or Threatened Australian Plants CSIRO Collingwood - in which it is given a coding 3R+.]

3. Zannichellia palustris occurs in fresh to brackish, still to slowly moving waters.

4. Recent collections of Zannichellia palustris in NSW are from Ironbark Creek and tributaries at Shortland and Wallsend, in Black Creek at Cessnock and in ponds on Kooragang Island. It has also been recorded from near Belmont.

5. NSW populations of Zannichellia palustris behave as annuals, and die back completely each summer. The individual patches of  Zannichellia palustris range from about 5m2 to 100m2 , but vary from year to year.

6. None of the known sites of Zannichellia palustris in NSW are formally protected, and none are managed in any way for the conservation of the species.

7. All the known sites are in areas where considerable changes have, and are continuing, to take place in their catchments. These changes in catchment land use may result in changes in hydrological conditions and water quality, which may affect the ability of the species to persist in areas where it is known to occur.

8. In view of 4, 5, 6 & 7 above the Scientific Committee is of the opinion that Zannichellia palustris L. (Zannichelliaceae) 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: 12/6/98
Exhibition period: 12/6/98 to 17/7/98