National recovery plan for Boronia granitica (Granite Boronia)
NSW National Parks and Wildlife Service, July 2002
ISBN 0 731 36889 4
9 Previous actions undertaken
No practical management efforts aimed directly at recovery or protection of Boronia granitica have been instigated on private lands. The establishment of Kings Plains NP and Severn River NR and their additions, as examples of intact land systems on the predominantly agricultural north-western slopes, have made a significant contribution to the conservation of the species on public land.
After surveying the vegetation of the Torrington SRA the Division of Botany, University of New England, has been further contracted by the NPWS to carry out initial research into components of the fire ecology of Torrington's threatened flora. Preliminary results are reported in this plan.
As part of the Comprehensive Regional Assessment of forests, the NPWS modelled a select group of 'critically threatened' species, including B. granitica, and convened an expert workshop to derive provisional population viability analyses (PVAs). The preliminary 'biophysical envelope' model developed for B. granitica appeared too broad for an effective distribution predictive tool (Summary outcomes of the CRA Threatened Flora Expert Workshops, July 1998).
The underlying reasons for the natural rarity of Boronia granitica are poorly understood but may include poor dispersal ability, fire sensitivity and competitive exclusion from more favourable habitats. The fire-shadow and 'refuges' model discussed by Gill and Bradstock (1995) predicts that areas such as boulder outcrops would support more 'seeder' species than the surrounds. This fire refugial aspect of outcrops is likely to be just one of several factors confining many shrubs to rocky outcrops. Other interacting factors may include physiological tolerance of shallow soils and the absence of trees (Clarke et al. 1998).
Given the estimated size of B. granitica populations in the Severn River, Kings Plains, Torrington and Howell areas and the reservation status of the first two areas there appears no absolute constraints to the long term viability of the species. Options to reduce the likelihood of population decline include feral animal control and careful fire management. The success of the latter is likely to be assisted by an improved understanding of the species' fire ecology gained from research initiatives.
The overall objective of this recovery plan is to protect known populations of Boronia granitica from decline induced by non-natural agents and to ensure that these populations remain viable in the wild in the long term.
Specific objectives of this recovery plan are to:
- improve the long-term viability of reserved populations;
- improve the viability of known non-reserved populations;
- determine if further populations exist on granite outcrops elsewhere on the New England Tablelands;
- increase our understanding of the ecology of B. granitica; and
- identify and ameliorate threatening processes.
Recovery criteria are:
- cessation of feral goat browsing at the Parlour Mountain location and reduction of goat (and stock) interference at Howell;
- reduction in feral goat populations in NPWS estate to a minimum;
- an improved understanding of the biology and ecology of B. granitica is sufficient to enable management for long-term viability of the species in NSW;
- reserved populations do not suffer any reduction due to human induced causes;
- populations that are not reserved are protected by appropriate measures;
- evidence of seedling establishment and recruitment at all or most population areas; and
- site monitoring to indicate population stability (given natural fluctuations).