Quick Dips

A Plea for Fungi

Some of New Zealand's estimated 20,000 species of fungi are in danger of becoming extinct, even before they are recognised.

"While media focus attention on a few iconic endangered organisms -- mostly warm and feathery -- a much more subtle loss of biodiversity is occurring almost unnoticed," says Dr Peter Buchanan, of Landcare Research.

He heads a PGSF-supported programme that aims to identify, describe and illustrate New Zealand fungal species. He says he is looking particularly at those that are important in nutrient cycling -- the breakdown of dead wood, leaves and other plant matter -- and those that are pathogens of plants.

Complicating the job is that only 25% (about 5,000) of New Zealand's fungal species have been recognised.

One endangered fungus is Ganoderma, which is related to overseas species of importance as a source of medicinal products. Buchanan says it is a wood-decay fungus forming large and conspicuous bracket-shaped fruit-bodies, and it used to be found on pukatea trees in Waikato.

"The fungus has not been seen since the early 1970s, despite searches by staff from the Department of Conservation, Forest Research, and Landcare Research."

Another species, Puccinia, is a microscopic rust fungus that lives only on the giant sow thistle, forming its spores in pustules on leaves. The giant sow thistle is found only on the Chatham Islands, and it is endangered, too. The rust fungus grows on only some of the plants, so is arguably more endangered than its host.

Buchanan's research programme manages the national collections of dried specimens (60,000) and living cultures (5,000) of fungi. The collections document where and when fungi have been collected, help in the identification of unknown fungi, and store plant disease records which are important for effective quarantine for New Zealand and several Pacific countries.

"Our work to document the biodiversity of New Zealand supports the Government's obligations as a signatory of the Earth Summit's Convention on Biological Diversity," Buchanan says. "The research is also important for biosecurity, to document what's in New Zealand and, just as important, what is not here -- the latter includes many species that could endanger plant health if they gained entry."

He says fungi are the main agents of decay of plant matter, but insects and bacteria also contribute. "So without fungi, fallen trees and leaves would simply accumulate on the ground. Nutrients would be locked up in this biomass instead of being recycled into the soil, and plant growth would thus suffer."

Buchanan says the world would indeed be "completely different and non-functional without fungi. In addition to decay fungi and those that assist the nutrition of most plants, other fungi highly beneficial to mankind include those we eat, the edible mushrooms and the yeasts used in wine, beer, cheese and bread-making, as well as those from which medicines are produced, such as penicillin and cyclosporine.

"New Zealand's fungi constitute a vast and largely untapped resource for biotechnological development and, as such, they are equally deserving of conservation as are our more charismatic species."