Eucalyptus camaldulensis in the Hunter Catchment - endangered population listing

The Scientific Committee, established by the Threatened Species Conservation Act, has made a Final Determination to list a population of Eucalyptus camaldulensis Dehnh. in the Hunter Catchment as an ENDANGERED POPULATION in Part 2 of Schedule 1 of the Act. Listing of endangered populations is provided for by Part 2 of the Act.

NSW Scientific Committee - final determination

The Scientific Committee has found that:

1. Eucalyptus camaldulensis Dehnh., River red gum, is the most widespread eucalypt in Australia, found in all mainland states and territories (Hill 2002, Brooker and Kleinig 1999).

2. In NSW, Eucalyptus camaldulensis occurs along the western flowing rivers but  is known from only one coastal catchment, the Hunter. The western-most individuals in the Hunter are at Bylong, south of Merriwa, and the most easterly at Hinton, on the bank of the Hunter River, in the Port Stephens local government area. The closest known population in a western catchment is at Mudgee, some 50 km from Bylong. It has been recorded in the local government areas of Lithgow, Maitland, Mid-Western Regional, Muswellbrook, Port Stephens, Singleton and Upper Hunter.

3. Prior to European settlement, it is likely that Eucalyptus camaldulensis formed extensive stands of woodland and open woodland on the major floodplains of the Hunter and Goulburn rivers, especially in areas where water impoundment occurs after flood (T Peake pers. comm.). Since settlement, most of the floodplains have been cleared of woody vegetation. Flood mitigation works now prevent most minor floods from inundating floodplains. These flow changes, coupled with the clearing of native vegetation, have greatly reduced the extent of habitat favourable to  Eucalyptus camaldulensis in the Hunter catchment.

4. Prior to European settlement, between 10,000 and 20,000 ha of habitat suitable for Eucalyptus camaldulensis occurred in the Hunter catchment. Today, there are only 19 known stands, occupying at most  c. 100 ha, the largest remnant being 15 - 20 ha in extent. The total number of individuals is estimated to be between 600 - 1000 mature or semi mature trees. Smaller remnants contain only one to several trees. Most of the occurrences are on private land and there are no known occurrences in conservation reserves (T Peake pers. comm.).

5. Eucalyptus camaldulensis may occur with  Eucalyptus tereticornis,  Eucalyptus melliodora,  Casuarina cunninghamiana subsp.  cunninghamiana and  Angophora floribunda.

6. Regeneration of trees is not occurring in most remnants because of changes in hydrology, cropping and grazing of the understorey or weed infestation by species including Galenia pubescens, Pennisetum clandestinum (Kikuyu) and  Ricinus communis (Castor oil plant) .

7. Tree dieback, from a variety of causes, has resulted in tree mortality and loss of vigour in a large proportion of trees.

8. Planting of Eucalyptus camaldulensis from non-local provenance introduces a potential threat to the genetic integrity of the Hunter catchment population (Hill 2003).

9. As a result of the decline in size of the population, its fragmentation, and current lack of regeneration, the Eucalyptus  camaldulensis Dehnh. in the Hunter Catchment is in danger of extinction. The population is disjunct and at the limit of range of  Eucalyptus camaldulensis, may be genetically distinct, and is of conservation significance as the community dominant in distinct riparian and floodplain vegetation types.

10. In view of the above the Scientific Committee is of the opinion that the population of Eucalyptus camaldulensis in the Hunter Catchment is eligible to be listed as an endangered population because it is facing a high risk of becoming extinct in nature in New South Wales and it is of conservation value at the State or regional level for the following reasons: it is disjunct or near the limit of its geographic range and it is otherwise of significant conservation value.

Dr Lesley Hughes
Chairperson
Scientific Committee

Proposed Gazettal date: 29/4/05
Exhibition period: 29/4/05 - 24/6/05

Reference: 

Brooker MIH, Kleinig DA (1999) Genetic pollution: concepts, concerns and transgenic crops. In 'Gene flow and agriculture: relevance for transgenic crops. British Crop Protection Council Symposium Proceedings No. 72'. Keele, UK. (Ed. PJW Lutman) pp. 67-72. (British Crop Protection Council: Farnham)

Hill K (2002) Eucalyptus. In 'Flora of New South Wales. Volume 2 (revised edition)'. (Ed. GJ Harden) pp. 96-164. (University of New South Wales Press: Sydney)

Hill L (2003) 'The Impact of the Proposal to Plant Eucalypt Hybrids at 'Derowen,' near Wollar'. Prepared for the Department of Infrastructure, Planning and Natural Resources