Botanist Newsletter

Issue No. 27, August to October 1999

Ecological Heritage Sites

The following sites were visited as part of the monitoring required by the Resource Management Act:

• EHS 15.06 (Corner of Wilmers Rd and Springs Rd) is a native grassland site owned by the CCC. At the time of our visit, the grass was long and the site not grazed. Since the smaller native species present benefit from moderate grazing (e.g. Muehlenbeckia axillaris, Leucopogon fraseri), the Property Unit has arranged a grazing lease. This is on a month by month basis so that grazing effects can be monitored, and the intensity of grazing can be adjusted if required.
• EHS 28.07 (Mt Pleasant) is one of the grassland/shrubland sites on the Port Hills. It is a mixture of Crown land managed by the CCC (Mt Pleasant Reserve) and private property.
• EHS 6.44 (South of School Rd) is another grassland site, but this one is owned by CRC and leased for farming. The site has a very high percentage cover of native herbs, mosses, lichens and grasses. There are also some native shrubs that are suffering from grazing (prostrate kowhai, Olearia virgata, matagouri, Carmichaelia australis). Some of these plants would benefit from being fenced off .

Bottle Lake

An assessment of this site, which is now a wetland within Windsor Golf Course, was carried out in September. Information on plants, birds, insects, fish and water quality has been compiled (Water Services Unit (1999) Bottle Lake Wildlife. Preliminary Assessment).

The site was a lake until early this century, but there has been considerable modification of the general area due to farming, sand drift control, wartime preparations, and latterly drainage for recreation. In addition, natural infilling due to sand drift and successional processes has resulted in the original lake bed being raised. This has been accompanied by woody plants covering the ‘lake’ with a thicket of swampy woodland.

The site is dominated by grey willow and alder, with a substantial understorey of blackberry, elderberry, cabbage tree, native and exotic ferns, and mosses. The margins of the area have a greater array of native wetland species including sedges, rushes, and forbs. In terms of current botanical status and potential, this site provides a valuable part of the overall complex of reserves and wildlife habitat in the eastern City.

Related Info: Bottle Lake Forest Management Plan

Aerial Photographs

The availability of aerial photographs as a layer in the councils GIS has resulted in an increased demand for maps. The aerials provide visual context for a number of uses. For example, a combination of aerials and the land parcel layer is facilitating the capture of management information for the Port Hills Reserves.

The Parks and Leisure Units have recently had an additional set of aerial photographs taken of about 120 parks. They cover most of the major and regional parks and sports fields. These are available as printed copies only (i.e. they are not set up to be used in the GIS), but they are recent and they are very clear. For further information regarding which areas are covered contact Ian Jackson (x 8796).

Horseshoe Lake

A weed list has been compiled for this site and the species have been listed in order of priority for control. Horseshoe Lake has sizeable areas of high quality wetland but there are also significant weeds present, including "surveillance" and "containment control" pests. Maintaining the existing natural areas within Christchurch often requires significant input into weed control, especially for wetland sites.

Bexley Wetland Local residents have formed a trust to look after Bexley Wetland. Their objectives include developing the wetlands educational, scientific and recreational aspects, restoring and preserving the native flora and fauna, and fostering community interest and involvement in the site. Bexley Wetland was one of the sites discussed at the recent Habitat Restoration Event organised by WEA.

For further information contact Mia Colberts Ph. 3822 987 or Hap Hill Ph. 3888 871

Reading List

A list or reading material related to Ecological Heritage Sites is now available. The pamphlet will be available to the public and is referred to in the upcoming EHS pamphlet.

Plant Identification

The number of plants sent in for identification has been low over the winter period but is starting to pick up again. Works Ops staff working along the waterways are noticing a wider range of native plants. These include water milfoil (Myriophyllum propinquum) and mudwort (Limosella lineata).

Planting Lists

Water Services is compiling a list of exotic species that are suitable for planting along streamside margins in Christchurch. Species on the list will be both aesthetic and non-weedy. Planting species with weed potential is a particular issue for waterway margins because they are more vulnerable to weed invasions than most other environments. This is due to their disturbed nature and because they act as efficient corridors to spread species.

Related Information: Bexley Wetland Newsletter