Botanist Newsletter
Issue No. 30, June 2000 to January 2001
Contents
Christchurch Naturally
A book about biodiversity in Christchurch has been completed by the CCC and is now available from many bookstores, City Council Service Centres and libraries ($24.95 each).
The book is well illustrated with many photographs and drawings and it provides information on the city’s Coast, Wet Plains, Dry Plains, Port Hills and Urban Christchurch. It includes ecosystem diagrams, list of sites to visit within each ecosystem, and an environmental contacts list.
Figure 1. Christchurch Naturally book, now available ($24.95).
Ecological Heritage Sites Pamphlet
This pamphlet is now completed (Figure 2) and available; a copy is attached.
If you would like more copies please contact Jenny Ridgen (jenny.ridgen@ccc.govt.nz or Ph. 9418 407).
School Resource Kit
A school resource kit has been developed for Ecological Heritage Sites that explains:
- What Ecological Heritage Sites are.
- The four main types of site (coastal dunes, native shrubland/forest, grassland/shrubland, wetlands and riparian areas).
- The value of Ecological Heritage Sites in Christchurch.
- Planning issues.
- Policy framework.
- Other sources of information.
These are available to schools, at cost (20c each). Please contact susan.meaclem@ccc.govt.nz (or Ph. 9418953) if you are interested in obtaining copies.
Figure 2. Part of one side of the Ecological Heritage Sites pamhlet, now available (free!).
Egeria
Following consultation with a number of different organisations, the council has decided to aim for a high level of control for the weed egeria. The high level of control is required to reduce the spread of egeria to other sites, but eradication is not considered to be a realistic option.
A range of different control methods have been tested, including mechanical harvesting, suction dredging, bottom lining and hand weeding. None of these were capable of achieving a high level of control, although they may all be useful as additional methods to keep egeria under control.
It was therefore decided to trial the use of the herbicide diquat, which is used successfully to control egeria in the North Island.
A trial application was made on January 15th (Figure 3). This was authorised by a Resource Consent and required closure of the river for 24 hours (Figure 4).
Information and training have been provided to rangers and City Care staff who are participating in the control and education. They also have the potential to find further sites.
Further information on egeria and what the CCC is doing to control it is available on the Councils web site www.ccc.govt.nz/guides/egeria/
Figure 3. Boat outfitted for diquat application.
Figure 4. 24 hour closure of the waterway following diquat application.
EHS Monitoring
Monitoring of Ecological Heritage Sites is an ongoing requirement of the Resource Management Act. Sites recently visited include:
- EHS 1.33 (Conservators Rd, north-east).
This site has a number of kowhai trees and matagouri bushes. It is also one of the few remaining sites on the plains with silver tussock.
- EHS 21.15 (Scott Estate, true right).
This site is predominantly forested and it includes some impressive totara and ngaio trees.
Figure 5. Ngaio (Myoporum laetum) at Hoon Hay Valley.
Weeds
Of particular note recently has been the amount of fatsia (Fatsia japonica), which is starting to spread along the river banks and is also quite prolific within Horseshoe Lake Reserve.
Several other species are also being targeted for control including African feather grass (a progressive control plant pest) and purple loosestrife.
Control of cord grass (Spartina anglica) is continuing at Calders Green Reserve. This species is a surveillance plant pest in Canterbury but we are keen to eradicate it if possible from the relatively few locations where it occurs within the city boundary.
Figure 6. Cape daisy (Arctotheca calendula) is a weed of lawn, sportsfields, and the Port Hills.
Weed Research
A detailed search of weeds along the Avon riverbank between Banks Ave and Wainoni Rd generated a large number of locations and at least 17 different species. Weed control is an ongoing area of work and control effort needs to be targeted as much as possible.
Some preliminary research into control methods for weeds has begun. The types of issues being considered are:
- How can we reduce the loss of non-target species? It is particularly difficult to achieve control of weeds when they are closely mixed with native species.
- How can we minimise herbicide use?
As well as finding alternatives to herbicide, it may be possible to minimise their use, through looking at which herbicides are used, rates of application, use of surfactants and timing of herbicide application.
- What are the most cost-effective methods?
- What methods can be used on some of the newer / less well studied species? (e.g. grey willow (Salix cinerea), purple loosestrife (Lythrum salicaria), boneseed (Chrysanthemoides monilifera), cape daisy (Arctotheca calendula, Figure 6), Spanish heath (Erica lusitanica), yellow flag (Iris pseudacorus), convolvulus (Calystegia silvatica), blackberry (Rubus fruticosus) and male fern (Dryopteris filix-mas).
- Can our planting designs be modified to reduce subsequent weed maintenance costs? e.g. using shade to reduce weed establishment.
If you are aware of any particularly good references or sources of information, we would love to hear from you.
Grazing
The generic grazing licence that the Council will be using for the Port Hills is now completed and we will begin the process of finding suitable licensees for each reserve. A valuation of the licence for Scarborough Hill Reserve will serve as a ‘test case’ to determine how the process will work.
After a few more corrections have been made, the Vegetation Management Strategy for the Port Hills Reserves will be circulated to interested members of the public for their input.
Monitoring of Grassland on the Port Hills. Permanent transects have been established within the grassland areas of Council reserves on the Port Hills. Baseline botanical information has been recorded for 57 plots. This will enable us to determine whether grazing levels are appropriate and to monitor any changes in the composition of the grasslands.
Native Gardens Award
This award has been instigated, in collaboration with the Canterbury Horticultural Society, for outstanding gardens representing and displaying New Zealand native plants and habitats in Christchurch (Fig. 7).
The aim is to recognise both private and community owned gardens that demonstrate a notable contribution to Christchurch’s natural heritage and biodiversity. These gardens will also contribute to the quality of the wider landscape and the City’s international reputation for diverse gardens.
New Zealand Ecological Society Conference. This was held in Hamilton in November 2000. Attached for CCC staff is a summary of some of the sessions attended.
Figure 7. Heliohebe lavaudiana, which is endemic to Banks Ecological Region.
Rock Climbing
There has been some ongoing liaison by Council rangers with some of the rock climbers that use the Port Hills. There is concern that their activities can be quite damaging to rock flora. The rocky bluffs are where many of the rarer species on the Port Hills occur, so it is particularly important to look after them. However damage could be minimised if the climbers were aware of potential problems and what to look out for.
One of the newer reserves the council has purchased comprises the bluffs on the true right of Heathcote Valley. The reserve is also an Ecological Heritage Site. This is proving a very popular site and has precipitated action on this issue.
Information and pictures of particular species has been provided. Several talks have been given by rangers to groups of climbers and signs for individual plants are being worked on.
Photographs
Photographs of some of the notable species on the Port Hills were taken over the spring/summer period. These include
Pygmy button daisy (Leptinella nana, Figure 10) – This plant is endangered and is a Category A species in the DoC system (i.e. highest priority for conservation action).
Blanket fern (Pleurosorus rutifolius, Figure 9) – Rare in the Banks Ecological Region
Heliohebe lavaudiana (Figure 8) – Endemic to Banks Ecological Region (i.e. Port Hills and Banks Peninsula).
These photographs are available for publications and educational material.
Photographs were also taken for use in the Travis Wetland display, including photographs of rushes, sedges and weeds.
Figure 8. Blanket fern, which is rare in Banks Ecological Region.
Figure 9. Pygmy button daisy, one of our threatened species.
Titoki Database
This is the Waterways & Wetlands Project database. A significant amount of work has been done on increasing the accuracy of the information contained within the database and this is now being reflected in an increased amount of use. |
