Botanist Newsletter
Issue No. 34, May to August 2002
Contents
Mt Pleasant Bush (EHS 29.04)
A valuable remnant of forest on the Port Hills has recently sparked interest in Telecom, who owns the site. As well as fencing the site (as required under the City Plan) they are planning to fell the pines that visually dominate the site and carry out some weed control.
The site is one of the few remnants of forest remaining on the northern side of the Port Hills, and even includes a matai tree. It is also home to a threatened species - the small-flowered mistletoe (Ileostylus micranthus).
Figure 1. Ecological Heritage Site 29.04 - a remnant of native bush on Telecom-owned land
Grazing of CCC Reserves on the Port Hills
Various interested parties have been consulted on the grazing plan for council reserves on the Port Hills. The report has been updated based on the comments received and will go to the councils' Park, Gardens and Waterways committee in September.
The grazing report also provoked comments on a number of other Port Hills related issues, which will be dealt with in a different forum.
Ecological Heritage Site Monitoring
Monitoring of Ecological Heritage Sites has included EHS 1.33 (Conservators Rd). This site includes a council reserve. Management of the reserve is to be primarily by the councils rangers and several visits have been made with them, as well as to record the trees and shrubs present.
Chilean mayten
Chilean mayten (Maytenus boaria) is a tree that the council has previously grown for horticultural purposes. It is a native of Chile and a member of the Celastraceae.
Until recently, it was only thought to be present, in Canterbury at least, as male plants. However female plants are now present as well and plants are establishing from seed. Joe Cartman at the City Council nursery has noticed this species has begun spreading.
The plants sucker vigorously and eventually form extensive colonies of stems at some distance from the parent tree. Female plants produce small fruits with red oily flesh and one to two seeds inside (which birds disperse).
Figure 2. Foliage of Chilean mayten
Chilean mayten is proving difficult to control. So far plants have proved quite resistant to herbicide. Some of the plants in the council nursery were drilled and the holes filled with 60% Roundup solution. This only killed about half the treated stems. In contrast, this method has a 100% kill of hawthorn, spindleberry, sycamore and Eucalypts elsewhere in the same shelterbelt.
We are particularly concerned at the potential weediness of this species as it appears able to colonise areas that are relatively undisturbed and densely shaded. It is bird-dispersed, tall, long-lived and difficult to control. Also of concern is that it looks similar to a lot of native plants with its small evergreen leaves, so it "blends in" very well and plants are difficult to spot.
As always, it is difficult to decide to do something when there are apparently small numbers of plants, in an initial stage of establishment. Nevertheless, now is the most cost-effective time to undertake control measures.
A brief report has been written that aims to raise awareness of this species and to promote increased surveillance and/or control.
Figure 3. Foliage and fruit of Chilean mayten
CCC Weed Team
A Christchurch City Council "weed team" has been set up to improve information sharing and to collaborate on some strategic projects. The team includes a range of staff that link back into other teams, including rangers and maintenance staff. This should improve communication between staff and enable us to share information more easily. Liaison will also occur between this team and the existing "weed liaison team" comprised of Department of Conservation, Environment Canterbury and Christchurch City Council staff.
Weed Strategy
A Parks & Waterways "weed strategy" is underway. This will enable the Unit to co-ordinate and prioritise weed control expenditure and effort, to achieve the maximum effect.
Essentially the strategy is a summary of the various plans we have in place, and what still remains to be done. The work has been grouped into 'weed-led' and 'site-led' projects, similar to the Department of Conservation approach.
We are trying a system where we initially sort the proposed work using several criteria:
- Any obligations under the Regional Pest Management Strategy (and therefore under the Biosecurity Act)
- The priority we give to protecting that habitat at that particular site
- The DoC 'weediness' score
- Whether the species is listed as an unwanted organism This generates an ordered list of species and sites.
The list is then examined to see if any inconsistencies are apparent. For example, a new weed may not rate highly because it does not yet have a weediness score or any pest status, but it may be worth making it the subject of a weed-led programme to pursue eradication.
Semi-automating most of the sorting in this way provides a transparent way of deciding what to work on each year with the allocated resources. It also breaks the work down into achievable pieces.
Information on costs is being collected. This will provide a basis for seeking any additional funding that may be required.
Reports
Recent reports produced include:
Cartman J, McCombs K (2002) Maytenus boaria - a new weed? CCCECO 02/06
Rare plants
There is an ongoing project to collect good quality images of the plants within Christchurch City boundary, including rare and threatened species. In February some images were taken of Myosotis australis var. lytteltonensis
Figure 4. Myosotis australis var. lytteltonensis
Otukaikino survey
A survey of botanical values in the Otukaikino project area is underway. The survey is covering the most north-western part of the city, essentially between McLeans Island Road and the stopbank for the Waimakariri River.
Coming up soon
Biodiversity Workshops
A team of staff and Councillors is currently working on developing a Biodiversity Strategy to identify and prioritise actions and methods that can be implemented in Christchurch to achieve national goals for biodiversity. A series of public workshops are to be held, to help with the development of the strategy.
- Mon 21st October, 5-7 pm @ Fendalton Service Centre, Cnr. Jeffreys and Clyde Rds, Fendalton
- Tues 22nd October, 7-9 pm @ Sockburn Service Centre, 149 Main South Rd, Sockburn
- Wed 23rd October, 10-noon @ Horticultural Society, South Hagley Park, 57 Riccarton Ave
- Tues 29th October, 7- 9 pm @ New Brighton Working Mens Club, 202 Marine Parade, New Brighton
- Thurs 31st October, 5-7 pm @ Linwood Service Centre, 180 Smith St, Linwood
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