快猫短视频

Rolling on the ground seems to be essential to life 鈥� at least in Africa鈥檚 Namib desert, where zebras bathe in dust, creating pits in the landscape that promote biodiversity.

The Namib desert is a vast stretch of dunes and mountains along the coasts of Angola, Namibia and South Africa. It is the world鈥檚 oldest desert and one of the driest.

Despite this extreme aridity, many animals and plants have adapted to survive, including the Hartmann鈥檚 mountain zebra (Equus zebra hartmannae). Herds live on the mountainous desert edge, migrating with rainfall. The zebras often roll in the dusty ground to groom and get rid of parasites. As part of this process, they hoof out large stones and displace the soil, making comfortable spots in which they rest and leave dung.

These pits can reach up to 30 centimetres deep and can last for years. at the Technical University of Munich, Germany, wondered if there were ecological benefits to this accidental landscaping. Over five consecutive rainy seasons, Wagner and his team calculated vegetation cover from drone images in more than 650 rolling pits, tracking the greening and wilting of the landscape following rains. They sampled soil and plant composition in 16 of the pits, using surrounding grassland as controls.

The researchers found rolling pits were mostly composed of finer soil and sand, instead of gravel. This allows rainwater to filter into the soil roughly twice as deeply as in nearby grassland, collecting like a pond and keeping the soil moist for longer. Levels of nitrogen and phosphates were higher too, probably because of the dung. The rolling pits were greener for longer, and were dominated by forbs 鈥� flowering plants 鈥� in place of perennial grasses. More plant-eating arthropods like short-horned grasshoppers and butterflies appeared, too.

Local farmers often see zebras as a problem, says team member Kenneth Uiseb at the . 鈥淭his project highlights the importance of zebras in ecosystem engineering, and the potential benefits they bring to the landscape.鈥�

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