Plant Conservation Initiatives in the Auckland Regional Botanic Garden, New Zealand
Volume 3 Number 4 - June 2000
A significant proportion (20%) of New Zealand’s flora is considered to be under some degree of threat and approximately 86% of these threatened plants are endemic. The New Zealand Government signed the Convention on Biological Diversity in 1992 at the Earth Summit and reiterated their commitment to the conservation of biodiversity in the recently adopted publication The New Zealand Biodiversity Strategy - Our Chance to Turn the Tide – Whakakohukihukitia Te Tai Roroku Ki Te Tai Oranga (February 2000) wherein the NZ. Government has pledged to play our part in halting global biodiversity decline.
It is estimated that 170 regionally/nationally threatened plants occur naturally within the Auckland Conservancy of the Department of Conservation (DoC). Auckland Threatened Plant Strategy, November 1998)
The Auckland Regional Botanic Gardens (ARBG) held a Among the numerous proposals to come out of Development Plan Working Party held in July 1997 were four related to plant conservation:
- Rare and endangered New Zealand (NZ) native plants should be cultivated in a special collection (Science Project Team).
- Endangered indigenous plant species collection to be established. (Education Project Team).
- The Gardens should become a resource centre for regionally threatened plants with a Threatened Plant Survival Unit and research facilities (Auckland Regional Council (ARC) staff submission).
- Endangered plant species collection to be established (ARC staff submission).
The ARC was approached by Central Government to submit a conservation project proposal with the aim of securing the donation from the Government of $100,000. The ARBG put forward a proposal for a threatened plant garden and a seed-based genebank for conservation which was successful.
Threatened Native Plant Garden (TNPG)
The site for the garden has been designated and the plan designed to fulfil the objectives of the Threatened Native Plant Garden (see Box). The main aims are plant conservation, education, horticulture and science . At present 7,000 school children attend our education programmes every year. On-site development is scheduled for May 2000 and design implementation is planned to be completed by November at the earliest (see Design of Threatened Native Plant Garden).
The Garden will have an emphasis on regionally and nationally threatened plants occurring naturally in the Auckland Region (in accordance with the draft ARBG Plant Conservation, March 1998 which came out of the Working Party), plants from northern offshore islands (as the ARBG is the most northerly botanic garden in New Zealand) and ensure that genetic variation present in wild populations is represented in the Collection including the distinct ecotypic variants.
The thematic collections will show ecological associations representing coastal and inland ecosytems including diverse habitats such as lava fields, gumlands, sand dunes, salt marsh, freshwater swamps and rocky bluffs. A species list of threatened plants documented in the Auckland Threatened Plant Strategy and published in 1997 by the Department of Conservation has been rearranged into ecological habitats and each species will be assessed as to whether it should and could be grown in cultivation. A list of associated and currently non-threatened species has been prepared and key species have been identified, material of known provenance will be sourced and herbarium voucher specimens collected. The sourced material will be planted as ecological associates with the threatened plants.
Geographic areas will be represented where plants are particularly vulnerable as on isolated islands with small populations adapted to specialised ecological conditions eg. Kermadec Is, Outer Hauraki Gulf Is. and Three Kings group. An area of ‘weedy’ looking threatened plants will be displayed showing that these plants have been overlooked because they are similar in appearance to our all too familiar weeds.
It is envisaged that breeding populations will be established where possible. It must be emphasised that ideally plants should be conserved as evolving populations in the wild. However, this is not feasible for every species and where threatened plants are at risk of extinction then conserving them in cultivation and seed banks are the only alternatives. Botanic gardens are the ideal organisations for rescuing and conserving species and utilising them for research and advocacy purposes.
Plant material will be collected from cultivated sources where the purity of such germplasm can be assured so as to not deplete wild populations still further. Those of known wild origin, which can be linked to a herbarium voucher specimen, are of the most value because they are usually accompanied by ecological information. If the plant material cannot not to be sourced in cultivation then collecting from the wild in consultation with DoC would be the second option.
The overall design complements the TNPG objectives (see Box), is responsive to New Zealand and South Pacific cultural usages and styles, has a sense of enclosure and provides a variety of stimuli to inspire children’s imagination and learning. A covered structure and paved area where people can gather and perform cultural events will be a focal part of the Garden together with an inviting entrance symbolic of New Zealand and the South Pacific cultures.
Objectives of the Threatened Native Plant Garden
- create an awareness of Auckland’s threatened plants and the reasons why they are in decline and what can be done to reverse the decline;
- assist in the identification of threatened plants;
- increase knowledge of the propagation and cultivation techniques of threatened plants and to disseminate this knowledge;
- provide a backstop against extinction of threatened plants in the wild;
- provide plant material for research, displays and cultivation thereby reducing pressure on the wild populations;
- provide an aesthetically well-designed thematic display to entice the majority of visitors into the Garden and inspire and instruct people how to take responsibility/action for their environment;
- promote where appropriate the wider use of threatened plants in amenity horticulture;
- provide plant material for species recovery programmes and translocation programmes;
- provide a resource for conservation biology, systematic research, propagation/horticultural related research, research into pathogen controls;
- increase public appreciation and awareness of the ARBG’s role as a scientific and educational resource;
- provide herbarium voucher specimens to the Auckland War Memorial Museum Herbarium.
Conservation-Specific Seed Storage Facility
ARBG will develop a comprehensive seed based genebank collection for threatened plants of the region. The initial aim is to capture 75-80% of all genetic variation within each regionally threatened species, and to utilize appropriate protocols for the long-term storage of seed from those taxa.
Genebanking can be readily incorporated into an integrated strategy for plant conservation. Seedbanking allows access to biodiversity material for research and a backup to prevent the loss of genetic diversity or as a last resort the extinction of the species. However, we are very much aware that a seed-based genebank is an ongoing project that will require constant financial resources, maintenance and enthusiasm from staff. We envisage that this will be shared.
Conditions of Storage at ARBG
- long term: seed is dried then stored hermetically at –18° C with moisture contents of 5% +/-1%
- medium term: active collections are likely to be larger than base collections with a more rapid depletion of seed. Temperatures for storage are held at 0-10° C with relative humidities of 15% or less
- short term: cool local conditions
As with the collection of vegetative material from the wild for propagation purposes all seed accessions will be accompanied with a voucher specimen to ensure that the accession can be verified and reassessed in the event of taxonomic reviews. This necessitates that the voucher specimen be numerically linked to the accession number. This will ensure information is maintained on its identity, provenance and history.
Auckland Plant Collections Network – Plant Conservation Working Group
Our Gardens are increasingly becoming a recognised institution for plant conservation in the Auckland region and beyond. In February the Gardens were represented at the Wellington Plant Conservation Network and were asked to speak on the proposed Threatened Native Plant Garden (TNPG) and report on the Plant Conservation Working Group of the Auckland Plant Collections Network. The Network was initiated six years ago by the Botanic Gardens and involves staff from botanical, conservation, horticultural, and educational disciplines.
Acknowledgements: We are most grateful to members of the Auckland Plant Conservation Working Group, especially to Peter de Lange (DoC), Rebecca Stanley (DoC) and Dr. Rhys Gardner for their technical assistance with project.