Dorrigo Daisy-bush is a single or multi-stemmed semi-herbaceous short-lived shrub which grows 1-2.5 m high and has alternate, crowded leaves which are more or less attached to the stem. The leaves are soft and slender, linear, 20-90 mm long, 1-5 mm wide, with a blunt but pointed tip. The margins are revolute and entire or occasionally with a few small scattered teeth. Both surfaces are hairless with indistinct lateral venation. Inflorescences are terminal in simple corymbs ranging from 19-25 mm in diameter. Ray florets number 30-48, are white in colour and often tinged with violet. The yellow disc florets number 39-50. Achenes are silky and the pappus has 36-50 bristles in one series. The peduncle reaches 52 mm long.
Dorrigo Daisy-bush |
Status: Endangered on the EPBC Act list
Government evidence of impact of climate change:
Australian Government, Conservation Advice, Olearia flocktoniae
Bushfires are predicted to increase in both frequency and intensity as a result of climate change and the species future response is uncertain.
Such changes in climate may cause Trend increasing widespread plant mortality in forest ecosystems; as Extent across the entire many plants are vulnerable to drought stress and range hydraulic failure (Allen et al. 2010 Choat et al. 2012).
Adult life stages are threatened by disturbance; mechanical damage; chemical and fire exposure and pollination disturbance from feral bees.
A high Trend increasing frequency fire regime ( four years) is likely to reduce Extent across the entire the population size of this species as it would not range allow time for recruits to grow and release sufficient seed.
Analysis by the Wildlife and Threatened Species Bushfire Recovery Expert Panel; based on intersecting the modelled distribution of the Dorrigo Daisy bush and the National Indicative Aggregated Fire Extent Dataset; indicates that approximately 32 of the Dorrigo Daisy bush range was within the extent of the 2019 2020 bushfire (Gallagher 2020).
Accordingly; they can invade Consequence moderate and establish in native vegetation; particularly Trend static following disturbance (D Antonio Vitousek 1992) Extent across part of its Invasions of introduced grass species can affect range ecosystems by altering system level rates of resource supply (e.g. nitrogen fixing grasses); as well as alter trophic structures; fuel loads and fire intensity and grazing disturbance patterns at ecosystem levels (D Antonio Vitousek 1992) Pioneer environments are quickly colonised by grasses and shrub species; potentially preventing the emergence of Dorrigo Daisy bush seedlings (Gross et al. 1998).