From Desolate Chunk of Rock to Darwin's Tropical Paradise: The Story of Ascension Island
Ascension Island's Old Water Catchment Area. "Green Mountain 2," by Lord Harris. Licensed under CC BY-SA 3.0 via Wikimedia Commons.
By Stewart Mittnacht, Science Writer
July 1836: A young Charles Darwin, nearing the end of his long voyage around the world, makes landfall on Ascension Island. One of the most remote islands on Earth, Ascension lies in the heart of the South Atlantic, more than 900 miles from the coast of South America. The island’s extreme isolation, geologic youth, and three centuries of environmental mismanagement—courtesy of the wild goats intentionally released on the island by Portuguese navigators—have left the island barren of soil and nearly void of plant life, with the exception of a few hardy fern and moss species. It is a hunk of lava rock upon which an impoverished ecology barely survives. Darwin felt that the British Empire could do better. Conspiring with his friend and confidant Sir Joseph Dalton Hooker, the two men set into motion a plan to improve the island.
An adventurer-scientist, Hooker helped to develop modern geographical biology, and his work proved critical in helping to popularize the theory of natural selection. When Hooker turned his attention to Ascension Island, his vast botanical knowledge would ultimately change the entire fate of the lonely rock.
“Within the first 20 years of planting, Ascension had already begun its transformation, boasting more than 40 new species of plants that had successfully adapted to the island’s conditions.”
Hooker reasoned that the ecological crisis on Ascension was derived from a singular problem: a lack of water retention. The island had adequate rainfall to support a more diverse ecosystem, but without loam, any moisture simply ran off the rocky surface and back out to sea. Trees, if planted, would provide three essential benefits to the island: they would assist in moisture capture; break down the lava rock with their root systems; and provide leaf litter, from which thicker soil might eventually develop. Hooker and Darwin developed a roadmap of potential species that might acclimate to the island, in some cases simply picking species that grew in a similar range of latitude, in other cases intentionally selecting mutually sympathetic species that would support one another. Within the first 20 years of planting, Ascension had already begun its transformation, boasting more than 40 new species of plants that had successfully adapted to the island's conditions.
Almost two centuries later, Ascension Island is host to an extremely diverse and self-sustaining ecosystem, arguably the first proven attempt at ecological engineering. Thanks to bioaccumulation, a thick layer of topsoil coats the island’s highest peak, now known as Green Mountain. Rain does not simply pour back out to sea but is retained by the island’s forests, providing a sustained and clean source of fresh water for the island’s human population. Native species are also rebounding; many of the formerly endangered endemic ferns have multiplied and prospered by adapting to a new niche. They now thrive as arboreal species, safe from goats on high tree branches.
Here at Blueprint Earth, our prime goal is to demonstrate that human genius, ingenuity, and science is a part of nature. We believe that with our minds and knowledge we might one day restore what has been broken, or even build a new ecology where none currently exists. Ascension Island is a rare proof of concept that demonstrates the enormous potential of who we are and what we can do.