Ecological Heritage Sites
This resource looks at the environmental, development and planning issues surrounding Ecological Heritage Sites (EHS) in Christchurch. It examines why the sites are highly valued by the people of Christchurch, what pressures are coming to bear on them, and what some of the relevant policy issues are.
Other sources of information are listed at the end of this fact sheet.
What are Ecological Heritage Sites?
Ecological Heritage Sites are areas of remnant indigenous vegetation with high ecological value.
All are within the Christchurch City boundary and were identified in 1993 when the Council employed specialists to carry out a survey of natural areas in the City. Five hundred sites were assessed and evaluated on various criteria including the number of native species, representativeness, unusualness, naturalness and the area covered by the site. Each site was assigned a rank and the top 49 sites are now identified as Ecological Heritage Sites in the Christchurch City Plan.
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Types of Ecological Heritage Sites
The sites are grouped into four broad categories, according to vegetation types:
1. Coastal dunes
The one site under this category covers the area from the Waimakariri River Mouth to South Brighton Spit. The main vegetation type is coastal dune grassland. This site includes many types of grasses, shrubs, herbaceous plants, rushes and sedges.
2. Native shrubland/forest
Most of the remaining forest sites within Christchurch are on the Port Hills. They include Jollies Bush, Dry Bush (Bowenvale Valley) and Hoon Hay Scenic Reserve. Forest plants found at these sites include totara, kahikatea, mahoe, lacebark and lancewood.
Riccarton Bush is the only surviving remnant of lowland swamp forest on the plains and is notable especially for its kahikatea.
3. Grassland/shrubland
Over half the Ecological Heritage Sites are a mixture of grassland and/or shrubland.
On the Port Hills, sites are often dominated by silver tussock and on dry plains grassland sites danthonia grass is more common (although silver tussock would once have been quite common on the plains as well).
Many other grasses, ferns and herbaceous plants also occur at these sites. Shrubs such as NZ broom and matagouri are another important component of many of these sites.
4. Wetlands & Riparian areas
Extensive low- lying areas of Christchurch were originally wetlands, and riparian (riverbank) areas were once much wider.
Ecological Heritage Sites in this category include Travis Wetland, Horseshoe Lake Reserve and riparian areas at the Groynes. Plants seen at these sites include sedges, rushes, raupo and flax.
Saltwater wetland sites include the Styx River mouth, Brooklands Lagoon and the Avon-Heathcote Estuary.
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The value of Ecological Heritage Sites in Christchurch
1. Ecological Heritage
Ecological Heritage Sites have been chosen to be representative of the range of landform/soil/plant associations that occur within Christchurch.
Sites are remnants of vegetation types that were once widespread.
Some sites have plants that only naturally occur on the Port Hills and Banks Peninsula. One example is Heliohebe lavaudiana, this small shrub has small round leaves and abundant white flowers.
2. Threatened Plants
Many sites provide an important habitat for locally and regionally threatened plant species. For example, Pleurosorus rutifolius is a rare fern found on the Port Hills.
The survival of this fern relies on the continuation of conservation measures.
3. Fauna – Native Insects and Birds
Many native insects and birds rely on Ecological Heritage Sites for habitat. Birds found at the sites include pukeko, pied oystercatcher, pied stilt, fantail and bellbirds. The Port Hills are the only place in Christchurch where the jewelled gecko can be found and is the area with the most concentrated population of common geckos.
Copper butterflies are one of the numerous indigenous insects that can be found on the Port Hills. A study of the dry grasslands of McLeans Island found 229 insect species of which over 150 occur only in New Zealand.
4. Education & Research
All sites provide an educational and scientific resource of benefit to the city’s schools and tertiary institutions. Sites on the Port Hills, at Travis Wetland and the Avon-Heathcote Estuary are already popular spots to visit for students of all ages. Clubs and societies also use many of the sites for activities such as bird or lizard watching.
5. Green Corridors
Christchurch has a network of open space, which plays an important role in linking these sites. These links provide “green corridors” which enable the movement of animals and plants between sites.
6. Ngai Tahu
Many sites are also important to Maori. For example, when land was first sold to European settlers, Maori requested Travis Wetland, an ancient Pa site, be reserved. Travis Wetland was also used as a canoe-landing site and for food storage. Similarly, the Avon-Heathcote Estuary was an important place for food gathering, a source of weaving material and a sacred site.
Certain areas on the Port Hills were important for burial and other areas contain important trees.
Related Information: Ti Kouka Whenua
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Threats to Ecological Heritage Sites
1. Weeds
One threat to Ecological Heritage Sites is how to protect them from weed invasion. Weeds are already a problem at many sites. For example, boneseed is spreading on the coast and on parts of the Port Hills, and grey willow is a particular problem on wetland sites. Other problem weeds include Spanish heath, gorse, wilding pines and old mans beard.
2. Pests & Predators
Family pets (especially cats), will disturb birds and often kill them. This is especially a problem for sites closely surrounded by residential areas, such as Riccarton Bush, Travis Wetland and Horseshoe Lake Reserve.
Possums, goats, rabbits, and stoats can also cause significant damage to plants and birds. These animals are prolific in some areas, especially on the Port Hills.
Planning issues for Ecological Heritage Sites
1. Urban Development
The majority of sites are owned either by the Christchurch City Council (CCC), Environment Canterbury (ECAN) or the Department of Conservation (DOC). About one third of the sites are in private ownership while others have been leased, usually for pastoral farming. Some conflicts have arisen with landowners who wish to develop land for agricultural or residential purposes. Development of this type can cause irreversible changes because they effectively displace the native vegetation.
It can be difficult to find the right balance between development and protection.
2. Recreation
Many Christchurch residents make frequent visits to Ecological Heritage Sites, especially the better-known sites on the Port Hills, around the Avon-Heathcote Estuary and Travis Wetland. A balance is required between allowing public access and the need to protect plants from damage and birds from being disturbed.
This problem has been addressed at Riccarton Bush by building a boardwalk, thereby protecting tree roots and seedlings from damage.
At other sites, tracks have been located to minimise disturbance to birds.
3. Public & Private Ownership
Before visiting any privately owned or leased sites, permission must be gained from the owner or leasee.
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Policy Framework
1. Agenda 21
At the Global Earth Summit held in Rio de Janeiro in 1992, New Zealand signed a document known as Agenda 21. Agenda 21 focuses on a number of issues, including the need to conserve global biodiversity, which concerns the variety and variability of genes, species, populations and ecosystems. As part of our contribution to global conservation, New Zealand has a moral obligation to maintain and enhance plants and animals unique to this country.
2. Resource Management Act 1991 (RMA)
The RMA requires that the City Council provides for the protection of significant areas of indigenous vegetation and significant habitats of indigenous fauna in its planning documents (the Christchurch City Plan).
The recognition of Ecological Heritage Sites in the City Plan helps to meet this requirement, and also carry out the Councils functions under the RMA, regarding the maintenance of indigenous biological diversity.
3. Biodiversity Strategy
Currently, some 1000 indigenous animal, plant and fungi species are under threat in New Zealand. The Department of Conservation and the Ministry for the Environment have developed a national biodiversity strategy that discusses strategies to preserve the many different and unique plant and animal species we have in New Zealand. Some of the strategy’s goals include improving the condition of protected land areas and the prospects for threatened species, managing the marine environment so that biodiversity is maintained and sustaining biodiversity on private land and in freshwater environments.
In order to contribute to the national biodiversity strategy at a local level the Christchurch City Council has developed a draft biodiversity strategy for Christchurch.
Other Sources of Information
There are many publications available with information relevant to Ecological Heritage Sites, including:
- The State of New Zealand’s Environment 1997, GP Publications.
- Natural Areas of Christchurch: Evaluation and Recommendation for Management as Heritage. 1993 (available from the Canterbury Public Library).
- Indigenous ecosystems of Otautahi Christchurch, Sets 1- 4. Lucas Associates (available from Christchurch City Libraries).
- The Christchurch City Plan, Policy 2.4.1, Volume 2 & Part 4, Volume 3, Christchurch City Council.
- Riccarton Bush, Putaringamotu: natural history and management, Edited by Brian Molloy.
- The Estuary, Where Our Rivers Meet the Sea, Edited by S J Owen.
Relevant information such as committee reports and newspaper articles can be sourced from the Aotearoa New Zealand Centre at the Central City Library, Gloucester Street – 941 7923 and the Christchurch Environment Centre), 64 Kilmore Street – 379 2257.
Librarians at the Central City Library are available to assist with research projects, as are staff at the Christchurch Environment Centre.
Other sources of information include:
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