National recovery plan for the Nightcap Oak (Eidothea hardeniana)
Threatened Species Unit, Western
New South Wales Department of Environment and Conservation, 2004
ISBN: 0 7313 6781 2
5. Previous Recovery Actions
- 5.1 Surveys and monitoring
- 5.2 Memorandum of Understanding
- 5.3 Management plans
- 5.4 Genetic studies
- 5.5 Ex-situ conservation
Extensive targeted surveys of potential habitat were undertaken in 2001 (Kooyman 2001). These surveys indicate that the Nightcap Oak is restricted to a limited area.
A large number of systematic surveys have also been undertaken on public land in north-east NSW (Brown et al. 2000, State Forests of NSW 1995, NPWS 1994; 1995; 1999a; 1999b). None of these surveys detected the Nightcap Oak. This reinforces the view that the species has a limited distribution.
A Memorandum of Understanding (MOU) between the former National Parks and Wildlife Service (NPWS) and the former Royal Botanic Gardens, regarding the Nightcap Oak was drafted. With these two agencies now part of the one Department, DEC, it is likely that a Service Agreement between the two divisions will supersede the MOU.
There are three management plans relevant to the Nightcap Oak. Issues related to the management of the Nightcap Oak in these plans are outlined below.
Parks and Reserves of the Tweed Caldera Draft Plan of Management
This plan states that actions in the Plan of Management will be superseded by any specific actions in a Recovery Plan for a species.
Nightcap National Park Fire Management Plan (in prep)
No prescribed burning is planned for Nightcap National Park. However, with the addition of substantial areas of eucalypt forest from State Forest to Service Estate, there is the possibility that the Fire Management Plan will propose some strategic burning for asset and property protection, as well as to protect sensitive vegetation types.
The Nightcap Oak
Pest Management Plan for Nightcap National Park
No areas of the Nightcap Oak habitat are priority areas for treatment in the Pest Management Plan (NSW NPWS 2001).
A comprehensive analysis of genetic variation in the Nightcap Oak including all known specimens and using specifically developed DNA markers (microsatellites), is being carried out by the BGT in Sydney after having been initiated at Southern Cross University at Lismore. Preliminary results based on three microsatellite loci (positions of a gene) suggest that allelic diversity and heterozygosity are surprisingly high for such a restricted species. There are no apparent signs of inbreeding across generations, with the levels of gene diversity within seedlings corresponding to those found in adult plants. This suggests that the Nightcap Oak is a preferential outcrosser (ie. breeding occurs as a result of mating between two unrelated / distinct individuals), and completion of the genetic study should confirm this. Outcrossing can be a perilous mechanism for a threatened species, as the loss of even a relatively small amount of diversity could significantly diminish its reproductive potential. The completion of in-depth DNA-based studies will provide more information on the recent evolutionary history of this species, and the possible effect of recent environmental changes.
Seeds and cuttings of the Nightcap Oak have been propagated at the Royal Botanic Gardens Mt Annan (RBGMA) (Offord and Azzopardi 2002). In addition, seed has been propagated at the North Coast Regional Botanic Gardens (NCRBG) at Coffs Harbour, and by Mr Barry Walker, Nimbin.
Seed germination success has varied from 0% to 71%, while germination periods varied from four to five months. Conversely, cuttings have proved to be far less successful where only one of ten cuttings has struck. Both the RBGMA and the NCRBG have the Nightcap Oak specimens as part of the living collection.
As indicated in Section 3.5 of this plan, it is anticipated that the seed viability period for this (and similar) species is likely to be short. It would, however, be of research value to test this assumption on seed storage behaviour for this species under a range of storage conditions at the BGT seedbank, when adequate seed is available.