Charles Darwin's Terraforming Experiment

Ascension Island, a British overseas territory in the south Atlantic, was originally a nearly-lifeless, uninhabited rock. It had no freshwater except for rainfall which quickly evaporated. But in an experiment, Charles Darwin and his friend Joseph Hooker introduced non-native plants that they hoped would encourage water retention. The result is that today Ascension Island has lush, vibrant forests.

Egged on by Darwin, in 1847 Hooker advised the Royal Navy to set in motion an elaborate plan. With the help of Kew Gardens – where Hooker’s father was director – shipments of trees were to be sent to Ascension.

The idea was breathtakingly simple. The trees would capture sea mist and moisture from passing clouds, collect rain, reduce evaporation and create rich, loamy soils.

So, beginning in 1850 and continuing year after year, ships started to come. Each deposited a motley assortment of plants from botanical gardens in Europe, South Africa and Argentina.

Soon, on the highest peak at 859m (2,817ft), great changes were afoot. By the late 1870s, eucalyptus, Norfolk Island pine, bamboo, and banana had all run riot.

Dr Dave Wilkinson is an ecologist at Liverpool John Moores University, who has written extensively about Ascension Island's strange ecosystem. He first visited Ascension in 2003.

"I remember thinking, this is really weird," he told the BBC. "There were all kinds of plants that don't belong together in nature, growing side by side. I only later found out about Darwin, Hooker and everything that had happened," he said.

Dr Wilkinson describes the vegetation of "Green Mountain" - as the highest peak is now known - as a "cloud forest". The trees capture sea mist, creating a damp oasis amid the aridity. Such ecosystems normally develop over million of years through a slow process of co-evolution. By contrast, the Green Mountain cloud forest was cobbled together by the Royal Navy in a matter of decades.

Dr Wilkinson exclaimed: "This is really exciting! What it tells us is that we can build a fully functioning ecosystem through a series of chance accidents or trial and error."