快猫短视频

Dotted along the arid coasts of Peru and Chile are islands of green space called fog oases that provide local sources of clean air, water and medicinal plants. The fog islands are poorly understood by scientists, but a satellite survey suggests they can grow across an area of land more than four times larger than previously thought.

鈥淚鈥檓 sure the local people living there know about them, but it gives us that knowledge of where it is in the landscape,鈥� says at Royal Botanic Gardens, Kew, in the UK. 鈥淭he understanding of how changeable these areas are is incredibly exciting.鈥�

Fog oases are pockets of green space within the desert where plants, including so-called air plants (Tillandsia) that can grow outside of soil, have adapted to capture water from fog coming into the land from the sea. The fogs are driven primarily by the Humboldt current, an ocean current flowing north along the west coast of South America.

Moat and his colleagues have combined 20 years of satellite imagery data to provide the most accurate map of these ecosystems to date.

鈥淭he vegetation is quite ephemeral,鈥� says Moat. 鈥淚t pops up [and] disappears. Sometimes, they may not be seen for five or 10 years and then they鈥檒l pop back up again depending on if the conditions are exactly right for them, which makes it incredibly hard to map.鈥�

Continuous fog coverage has also been a barrier to mapping these ecosystems via satellite, and the remote location of many fog oases means they are difficult to reach for direct study.

The fog oases, known locally as lomas or oasis de niebla, were thought to cover just 4000 square kilometres, but the team found that they actually extend for 17,000 square kilometres.

The fog oases react quickly to changes in sea temperature, which could allow them to serve as an early warning system for climate phenomena like El Ni帽o. This also means that these delicate ecosystems are threatened by climate change.

Sign up to Wild Wild Life, a free monthly newsletter celebrating the diversity and science of animals, plants and Earth鈥檚 other weird and wonderful inhabitants