Planting with native ferns can save devastated land

Research into indigenous New Zealand species is cutting the time it takes to rehabilitate devastated land with native plantings by a decade or more, says a company developing the plants.

Rural Supply Technologies, of Palmerston North, says it has already gathered knowledge about the establishment of native seeds and is now investigating revegetating with New Zealand ferns.

The research into ferns will "enable us to rehabilitate any site thrown at us", says managing director Robert Coulson.

Government finance of $48,000 had been invested through Technology New Zealand for research by two masters students at Massey University, Allison Mackay and Matthew Denton-Giles, with close involvement from Landcare Research.

Dr Craig Ross, a senior environmental scientist with Landcare and one of the research supervisors, said a layer of fern cover would help to stabilise banks without requiring mowing.

The project, overseen by Dr John Clemens, of Massey University, was breaking exciting new ground.

"We are dealing with spores for the first time, not seeds, and going right back to the basics of fern reproduction to learn what is the best micro-environment to get ferns established," he said.

"This knowledge doesn't exist anywhere else in New Zealand or the world."

Dr Ross said that generally New Zealand lagged well behind Australia in its knowledge about seeding habits of indigenous plants.

"There is plenty of information on identifying our native plants and their general ecology, but scientific knowledge about the behaviour of native seed is poor," he said.

"We just haven't done the work here to find out, for example, when is the best time to collect seed, how and why native seeds lie dormant and how seeds should be stored."

New Zealand would benefit from scientific collaboration and knowledge-sharing with Australia.

"The Australians have found that a specific compound in smoke enhances the germination of a lot of their native species and other plants, including lettuce. This technique could well speed up germination of our natives as well," Dr Ross said.

The technologies for native plants developed by Rural Supply are already being used on heavily disturbed sites such as those that have been mined or roadsides and hillsides where there have been massive slips.

Mr Coulson said the company was not creating superspecies, but speeding up the establishment of native seeds and fern spores.

"There are many sites where grasses and clover are not appropriate. In those places native plants would do the best job of returning the biological system to full health.

"They're also more picturesque."

The native seed was generally gathered by hand from plants at or near the damaged site, and the company had developed hydroseeding equipment which sprayed the seed with a fibre mulch, fertiliser, and a "tackifier" that stuck the seed to steep slopes.

The mixture was the consistency of porridge and the mulch cover created a moist, nutrient-rich thermal blanket that protected the seed as it established.

The two-year project to research native ferns has begun with a laboratory screening programme to determine which ferns can be established quickly at harsh sites where container-grown plants would not survive and conventional seeding was likely to fail.

- NZPA