Fairy Circles in the Namib

BBC News – Termites ‘engineer fairy circles’.

At 2 to 10m across, these previously unexplained formations were attributed to ‘fairies.’  Now we know the truth – they are created by termites to conserve water in the desert.

[the] invertebrates (Psammotermes allocerus) first clear a patch of ground by eating the roots of short-lived, annual grasses.

This bare, sandy earth then becomes an effective rain trap – with no vegetation, water cannot be lost through transpiration (the evaporation of water from plants).

Instead, it collects, oasis-like, just below the surface where it can sustain the termites and a supply of perennial grasses at the margins of the circles. These are available to eat even in the driest seasons.

Of course this permits and encourages even wider benefits  – lizards, geckos, moles, and other animals up the food chain rely on the termites.

…their occurrence hugs the isohyet of 100mm mean annual precipitation.

“It’s very pronounced; they’re really adapted to that amount of annual precipitation,” he told BBC News. “If the climate changed [to wetter conditions], this belt of occurrence would shift to a more arid part of the desert. If the climate got drier in general, they would shift towards the east, inland.”

These engineers allow the desert to increase productivity, much like the beavers in mountain environs.

The Hamburg scientist argues that the termites’ behaviour surpasses the accomplishments of that other great ecosystem engineer – the beaver.

“We all admire the beaver for the way it can turn a linear river into a lake with a dam, but the termites turning the desert into a pattern of oases that allow permanent life even in drought periods for hundreds of years – that’s much more fascinating,” he told BBC News.

How will climate change affect these animals and the ecosystem that relies on them?

 

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