Dillwynia tenuifolia population, Baulkham Hills Shire Local Government Area - endangered population listing

The Scientific Committee, established by the Threatened Species Conservation Act, has made a Final Determination to list the population of the shrub Dillwynia tenuifolia Sieber ex DC. in the Baulkham Hills local government area 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. Dillwynia tenuifolia (family Fabaceae) is not currently listed as an endangered species in Part 1 of Schedule 1 and as a consequence populations of this species are eligible to be listed as endangered populations.

2. Dillwynia tenuifolia is a shrub found mainly from the Cumberland Plain in western Sydney. A description is given in Harden, G.J. (ed.) (2002)  Flora of NSW Vol. 2, 2nd edition. p. 545. UNSW Press, Sydney.

3. An isolated population of Dillwynia tenuifolia occurs near South Maroota in the Baulkham Hills Shire local government area on soils derived from Wianamatta shale. This population is disjunct from other known populations which are on soils derived from Tertiary alluvium and is near the limit of the species geographic range.

4. The population of Dillwynia tenuifolia in the Baulkham Hills Shire local government area is threatened with further land clearing, road maintenance, weed invasion and an inappropriate fire regime. It is estimated that over 90% of the habitat of the population has been lost in the past through land clearing. The population occupies a small area and has low plant numbers making it threatened by environmental and demographic stochasticity.

5. The population of Dillwynia tenuifolia in the Baulkham Hills Shire local government area is considered to be of conservation value as its habitat and associated vegetation are different to those of the core distribution of  Dillwynia tenuifolia.

6. In view of the above the Scientific Committee is of the opinion that the population of Dillwynia tenuifolia Sieber ex DC. in the Baulkham Hills local government area 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.

Associate Professor Paul Adam
Chairperson
Scientific Committee

Proposed Gazettal date: 07/11/03
Exhibition period: 07/11/03 - 19/12/03