Climate change threatens world's iconic ecosystems

London: Without better local management, world's most iconic ecosystems are at risk of collapse under climate change, warn researchers.

Protecting places of global environmental importance such as the Great Barrier Reef and the Amazon rainforest from climate change will require reducing pressures like over-fishing, fertiliser pollution and land clearing, they said.

Writing in the journal Science, an international team of researchers warned that localised issues, such as declining water quality from nutrient pollution or deforestation can exacerbate the effects of climatic extremes such as heat waves and droughts.

"We show that managing local pressures can expand the safe operating space" for these ecosystems, they wrote.

"Poor local management makes an ecosystem less tolerant to climate change and erodes its capacity to keep functioning effectively," said the study's lead author Marten Scheffer from the Wageningen University, the Netherlands.

The authors examined three Unesco World Heritage Sites -- Spain's Donana wetlands, the Amazon rainforest and the Great Barrier Reef.

While many ecosystems are important to their local people, these ecosystems have a global importance too, hence their designation as World Heritage Sites. For instance, the Amazon rainforest is a globally important climate regulator.

Like coral reefs, rainforests and wetlands around the world, these sites are all under increasing pressure from both climate change and local threats.

For example, the Donana wetlands in southern Spain are Europe's most important wintering site for waterfowl, hosting over half a million birds and home to numerous unique invertebrate and plant species.

A warming climate could encourage more severe blooms, causing losses of native plants and animals, say the researchers.

"Local managers could lessen this risk and therefore boost the wetlands' climate resilience by reducing nutrient runoff," said co-author Andy Green from the Donana Biological Station.

He added that nutrient control measures could include reducing fertiliser use, improving water treatment plants and closing illegal wells that are decreasing inputs of clean water to the wetlands.

"Local management options are well understood and not too expensive," said Scheffer.