Spreading fertiliser on natural grassland can damage ecosystems, according to new study by an international group of researchers, including scientists at Trinity College.

The research, published in the international journal Nature, assessed the effects of fertiliser placed on 41 sites across 5 continents that were monitored by the team.

The theory they were exploring was whether fertiliser spread by farmers, coupled with nitrogen in the atmosphere that is brought to the ground by rainfall, was having an effect on the grassland.

The research found that it was destabilising the natural eco-system.

It discovered that when fertiliser is added, the "ecological safety net", which balances output from the various organisms across diverse grassland, is upset and disappears.

It found this to be true across a wide range of eco-systems, from alpine areas of China to the Serengeti in Tanzania.

"We showed that the compensating effect of plant diversity occurs in 41 natural grasslands all over the world, but the link between grassland biodiversity and biomass production breaks down when fertiliser is added," said Yvonne Buckley, Professor of Zoology at Trinity College.

"Fertiliser creates more variation in biomass production from year to year, and the species all tend to respond in the same way, rather than compensating for each other."

It is the first time an international experiment of this size has been conducted using naturally occurring sites.

According to the research team, it is important that we understand how grassland provide the services they provide, because of our reliance on such ecosystems for livestock production and the storage of carbon dioxide in the atmosphere.

It was made possible by NutNet, a grass-roots campaign supported by scientists who volunteer their time and resources to help standardise how ecology research is carried out.

Professor Buckley said it is important that Irish grasslands are included in the experimental network and she plans to set up at least one site in Ireland during the coming summer.