Southland's threatened plants

Forest and Bird, Issue 293, 1 August 1999, Page 10

Southland's threatened plants

A garden of threatened plants has been established, near Invercargill in Southland, by Forest and Bird members Chris and Brian Rance. They report on progress:

he main purpose of the garden is to teach people how to identify some of New Zealand’s rarest plants, and to understand the reasons for their decline. Work on the Southland Threatened Plant Garden began in 1994, with a successful application to Forest and Bird’s threatened plants programme when it was sponsored by Yates. Initially, the project focussed on increasing knowledge of the growing requirements and propagation techniques for some of Southland’s threatened plants — plants such as the endangered Gunnera hamiltoni, an endemic, groundhugging coastal herb, and the endangered Olearia hectorii, the deciduous tree daisy. We thought if the propagation work were successful, then the plants produced could be used for restoration, thereby boosting or protecting vulnerable wild populations. The possibility of creating a display garden for advocacy purposes was, at that stage, well into the future. Looking back, we have learnt an awful lot about threatened plants in Southland over those years. When the work on Gunnera hamiltonti commenced, there were only four known populations of this endemic plant in the world, each of a single sex, with the sex of each population unconfirmed. After pieces of plants from each site were taken into cultivation and studied, the mainland population flowered and was found to be female, while the Stewart Island population is male. Therefore each single-sex population is vulnerable and could only reproduce vegetatively. Further experimentation with hand-pollinating the plants in cultivation, resulted in the firstever recorded fertile seed, and later, seedlings of this species. There are now six wild populations known, with one discovered as recently as July 1998, although the sex of this population remains unknown. The deciduous tree daisy,

Olearia hectorit, was known from only 10 sites in Southland at the beginning of this work. Many sites were a single tree, or trees in paddocks surrounded by grass swards. No seedlings had ever been observed and many plants were on private land, and not necessarily protected from further development. This is the plight of many endangered species — while individual plants may be protected, their habitat is not. In order to produce back-up populations, propagation techniques needed to be found. Initially, cuttings of the tree daisy were difficult to strike, but this is now achieved readily, while the plant is still almost impossible to propagate from seed. To date, over 50 plants have been restored to protected areas in the wild, and more will be planted out by the Department of Conservation in the coming season. Similar work

has taken place with Olearia fragrantissima, Olearia ‘Pomahaka (an un-named species), Melicytus flexuosus, Teucridium parvifolium, and Euphorbia glauca, the shore spurge. Unfortunately many of the species referred to do not have common names — they are too uncommon for that! Success with propagating many of Southland’s rare plants, and the knowledge we gained about growing requirements, meant we could with confidence embark on the creation of the display garden. This was begun in October 1996 with the preparation of beds, paths and edging. The Southland branch of Forest and Bird helped with the work.. During that and the following year, four other display areas were created the Chatham Islands, Southern Islands, Southland Coast, and New Zealand General displays. In total there are more

than 70 garden specimens. Since its establishment, the display garden has been used for training field staff of the Department of Conservation in the identification of plants in the wild; and also by university botany students. Among features of the display areas are Cook’s scurvy grass — not a grass at all but a herbaceous plant related to cabbage — and now almost extinct on mainland New Zealand. Chionochloa spiralis and Hebe ‘akahe’ are found only in limestone areas of ‘takahe country’ in the Murchison Mountains of Fiordland. There are also fascinating divaricating shrubland plants such as Melicytus flexuosus and the fragrant tree daisy Olearia fragrantissima. Golden pingao — the native sandbinder — is still used by Maori for weaving. Special subantarctic island plants, known as ‘megaherbs’ which have evolved largely in isolation are on display along with the spectacular Chatham Island forget-me-nots and speargrasses. On our interpretation leaflet we call the garden ‘A Modern Noah’s Ark, because many plants contained within it form a back-up population in case wild populations are lost. Gardens such as this, like island sanctuaries for endangered birds, are hopefully only a temporary measure until threats in the wild can be removed — that may be a long shot but we must strive for it. Otherwise New Zealand will lose its uniqueness. A land of exotic forests and pasture, without our unique native flora, would be a very sad outcome for New Zealand. — Chris and Brian Rance. The Southland Threatened Plant Garden is open to the public by prior arrangement — phone Chris and Brian Rance, evenings (03) 213-1161.