Botanist Newsletter

Issue No. 24, January to March 1999

Monitoring of Ecological Heritage Sites

Site visits were made to EHS 14.07 (Travis Swamp) and EHS 3.13 (Groynes). Site visit reports are available to CCC staff in the Natural Areas Database (L:\Botany\NaturalAreas97.mdb). Several dry lowland grassland sites in the McLeans area were also assessed (EHS 1.29 and EHS 6.40).

Of particular note at these two sites was the detrimental effect that grazing is having on some of the bushes (native broom, Olearia, prostrate kowhai and matagouri). There are no seedlings below the kowhai trees either. While light grazing benefits the grassland (by controlling weeds) the long-term effect on regeneration of the trees and shrubs mean they may need additional management.

McLeans Invertebrate Report

A report on the invertebrate fauna of the McLeans grassland area was recently completed (Macfarlane RP, Patrick BH, Vink CJ (1999) McLeans Island Invertebrate Inventory and Analysis). It will soon be available from the Public Library or copies can be obtained from the Parks Unit, CCC.

229 terrestrial insect species are recorded in the area and around 80% of these are endemic to New Zealand. There are 4-9 undescribed insect species (including a 3 cm long nocturnal weta) and 2-3 undescribed spiders present.

Brooklands Lagoon

The weed plan for Brooklands Lagoon is progressing. One proposal is to introduce biological control agents to the area to help achieve sustainable and cost-effective weed control in the long-term. Biological control would be used in addition to other weed control methods.

Botanical Databases

The documentation for each of the botanical databases has been updated. The two main botanical databases currently available on the CCC network are:

Natural Areas,Detailed species records for more than 650 sites within Christchurch. It also contains site-related information such as soils, contact details of owners and managers, related publications. (L:\Botany\NaturalAreas97.mdb)

Weeds, Records weeds along Christchurch waterways as well as information on the action to be taken at each site and a schedule of work. (L:\Botany\WSU|Weeds97.mdb)

Vegetation History at Styx Mill Reserve

Landcare staff recently took a peat core at Styx Mill Reserve. This will enable them to determine what plant species have been present in the area in the past. The depth of peat is relatively shallow at the site, despite its swampy nature. The underlying substrate is river gravel.

Weeds

The new, improved, "Christchurch Waterway Maintenance Plant Guide" is now complete. This has pictures and descriptions of approximately 50 different species. Most of them are weeds, but there are some similar looking plants included for comparison where identification can be difficult; e.g. with the umbrella sedges. Many of the field staff now have copies of the guide. Additional copies are available to loan from the Parks Unit.

Weed Reporting

Works Operations field staff are regularly reporting problem weed sites and these reports are being collated in the Weeds Database. Once a month the information is summarised.
In addition, a sheet on "Plants of the Month" is being distributed regularly to field staff. This draws staff attention to species that are particularly visible at that time, e.g. because they are flowering. Improved weed identification will enhance our waterways and reduce long-term maintenance.

Bexley Wetland

Work has begun on a moat between the wetland at Bexley and the adjacent subdivision. Coastcare staff are supervising this and have saved some of the salt marsh vegetation being removed, so that it can be re-planted nearby.

New Zealand Biodiversity Strategy

A presentation of the draft strategy was recently held at Lincoln. The sub-title of the document is "Our Chance to Turn the Tide". This alludes to the fact that biodiversity in New Zealand is declining and will continue to do so unless we act. The "do nothing" option does not maintain the status quo in terms of species numbers, but rather it will result in further species loss.

A copy is available on the internet at http://www.biodiv.govt.nz. Comments are due by Friday 16 April 1999

Rare plants

A recent inspection with DoC of the rare daisy Leptinella nana, that grows on the Port Hills, found that the plant was looking relatively healthy despite the dry summer. One of the main threats at the site is from rock climbers who disturb the ground where the plants are growing.

Wetlands Information

The Water Services Unit is recording details on all of the wetlands within Christchurch, including potential ones. This will assist various activities including planning, budgeting and monitoring.

A map layer of wetlands provided to the CRC will assist them in monitoring wetlands in Canterbury. One of the indicators in the Canterbury Regional Policy Statement is to monitor the "trends in quality and extent of wetlands" (Section 8.5).

Waterwise Gardens

Water Services are producing a pamphlet to enable people that are interested to plant species with a low water requirement, thereby conserving water.