Olearia hectorii (Hectors tree daisy)
IntroductionOlearia hectorii, also known as Hectors tree daisy, is one of the most threatened members of New Zealand’s small-leaved tree daisy family.
Olearia hectorii is one of a very small group of New Zealand trees that are deciduous. Most of our trees and shrubs are evergreen.
Olearia hectorii is found only in the South Island and the total population thought to be around 4,500 individuals. Very few of these occur on protected or conservation land, but on private property.
Landowners, therefore, have an important role to play in the future of the species, both in being able to recognise the species and take an interest in its welfare and survival.
Its threat ranking is 'Nationally Endangered', mainly due to loss of habitat. This is especially the case in areas where older Hectors tree daisy specimens still exist, but are unable to regenerate. This is usually because of a lack of bare ground around them where seeds can germinate and emerge without competition from weeds or pasture plants.
Olearia hectorii or Hectors tree daisy is deciduous, up to 9.5m tall, with deeply furrowed, cork-like bark on the trunk and older branches.
Young branches and branchlets are smooth-barked and bronze-red with four ribs that produce a squarish cross-section.
Leaves are arranged in clusters of opposite pairs. They're a pale moss-green colour and roughly oval in shape. Flowers are in clusters of two to six, any time between October to early December, and can begin before the new leaves appear.
Having largish leaves means that within the Olearia group, O. hectorii only has similarities with Olearia fragrantissima. In winter its leafless state, form and bark are similar to elderberry. It is also often associated with lowland ribbonwood and kowhai.
Olearia hectorii primarily occupies wet, cold valley floors and hill slopes, often where mountain and hill-country streams disgorge onto the plains.
It also occurs as a riparian and forest margin species in some lowland areas, appearing to favour open sites that either are or were canopy gaps in primary forest margins and streamsides.
It relies on natural disturbance - flooding, sedimentation and erosion - to provide seeding sites. It can live for up to 150 years and it supports at least 22 moth species.
Olearia hectorii is restricted to the eastern South Island, after North Island populations were renamed Olearia gardneri.
O. hectorii's distribution is disjunct or discontinuous, occuring in Marlborough, then South Canterbury and throughout Otago and Southland.
Historical records show it previously occured in the gaps of its South Island distribution including eastern and southern Nelson and Northern Marlborough.
Total population size is approximately 4,500 individuals, from approximately 90 sites. The largest population occurs in Marlborough's Clarence catchment, where approximately 2,000 plants are known.
Two other relatively large populations consist of 600 plants in the Matukituki Valley and 300 plants in Southland's Upper Waikaia Valley.
Regeneration and recruitment are more-or-less absent in Canterbury, Otago and Southland, but does occur to some extent in Marlborough.
Threats include habitat loss and fragmentation, animal browsing, weed invasion, lack of seedling recruitment and loss of mature trees that could be a seed source.
Another threat is modified habitat where there is little natural disturbance, such as landslips. Land slides and flooding create open ground for germination and replacement seedlings.
Equally threatening for Hectors tree daisy is that the great majority of existing populations are of old, non reproducing trees. This means there is little replacement. In other words, as old trees die, Olearia hectorii will disappear from the landscape.
DOC has a recovery plan covering the eight rare, small-leaved tree daisies that Olearia hectorii belongs to. The recovery plan aims to secure viable populations of each tree daisy at sites that best represent its distribution and ecology. Achieving this requires controlling threats, providing physical and legal protection, improving the habitat, and enhancing populations at selected locations.
These protective steps are especially important for Olearia hectorii, as very few specimens are found on conservation land, most are on private property. The Small-leaved Tree Daisy Recovery Plan has several objectives.
- Make key stakeholders aware of the demise of our rare, small-leaved tree daisies, and gain their support for actions that will restore the species.
- Gain the support of relevant Iwi and involve them in the recovery of our rare small-leaved tree daisies.
- Determine sites that are representative of the original distribution and ecological variability of each species.
- Ensure that priority sites of rare small-leaved tree daisies are both secure and maintained.
- Develop management and research programmes that improve knowledge of tree daisy ecology and the range of threats to each species' survival.
You can help
- Learn to recognise the plant.
- Tell DOC staff if you discover populations of Olearia hectorii or even if you just suspect that you may have seen it.
- Explore ways to protect populations of Hectors tree daisy through covenanting, fencing, weed control and supplementary planting.
- Use locally sourced Olearia hectorii plants in gardens, shelterbelts, riparian and river works planting and other revegetation projects.
The aim of the factsheets is to encourage public awareness of these distinctive New Zealand species, to help people recognise the plants and take an interest in their welfare.
There are eight rare olearia species included in the Small-leaved Tree Daisy National Recovery Plan, of which the conservation status ranges from nationally critical to sparse.
Take a look at the individual species factsheets for photographs, descriptions, habitat requirements and distributions for each species which are distributed from the Central North Island to Stewart Island/Rakiura in the south.
If you discover populations of small-leaved Olearia or even if you suspect you may have seen it, tell DOC staff.
- Olearia adenocarpa (PDF, 158K)
- Olearia fimbriata (PDF, 140K)
- Olearia fragrantissima (PDF, 161K)
- Olearia gardneri (PDF, 151K)
- Olearia hectorii (PDF, 175K)
- Olearia lineata (PDF, 222K
- Olearia polita (PDF, 172K)
For more information, contact:
Olearia Recovery Group