The fat-headed ant prevents lions from hunting zebras

Sometimes small ants have a big impact on the ecosystem. This was written by an international team of biologists last week Sciences. An invasion of an exotic ant species has set off a ripple effect at a wildlife park in Kenya. The result is that the trees have disappeared and that lions now mainly eat buffalo.

A similar effect has previously been seen in Yellowstone Park in the United States. There, the reintroduction of wolves has caused rivers to resume their natural courses. Suddenly deer no longer dared to appear in the open valleys, allowing the forests to grow there again, causing the soil to change, and so on. A movie about it (“How wolves change rivers”) It went viral in 2014. It sparked a lot of discussion: Was it true? Yes, as ecologists have claimed, the process has been oversimplified at best. The reintroduction of wolves was the reality OperatorThe changing course of the river was indeed the result, but there were many more intermediate connections than just deer and their grazing.

complicated

Such chain reactions have not been explored in detail, American, Kenyan, Canadian, British and Argentinian biologists now write. Sciences. But it is very relevant. Because in order to effectively protect nature reserves and their species, we need to know more about their interrelationships. These are often complex and still partly misunderstood.

Take, for example, Kenya's Ol Pejeta Nature Reserve. This consists of savannah with acacia trees. Acacia ants live closely with native acacia ants. These ants eat acacia nectar and live in the thickness of its thorns. In return, the ants protect the acacia plants from grazing elephants. It is not yet clear exactly how this works. But previous research has shown Elephants hardly eat acacia plants when acacia ants live in them, and literally graze on them in their absence.

But in the past 20 years, a strange species of ant has taken over the area. It's about the full, shiny head from Asia. This has rapidly driven the acacia ants out of large parts of Kenya. Invasive ants not only compete with acacia ants for food, but also kill them and eat their eggs and larvae.

Alert and speed riders

And shiny heads do nothing for acacia trees. This allows the elephants to do their work: in recent years they have destroyed five to seven times as many acacia trees as there are acacia ants. This is how the trees in the Ol Pejeta area disappeared from the landscape. The lions couldn't find cover there anymore. This makes hunting zebras in particular more difficult: zebras are alert and fast runners, and can now escape more easily.

Lions can also eat other animals, such as African buffalo. They are less quick and alert, so no cover is needed to attack them. But buffalo are much more dangerous and difficult to kill. This is why lions prefer to eat zebras. But now, in the new open landscape, they have no other choice. Since 2003, the share of buffalo in their diet has increased from zero to 42 percent, and the share of zebra has decreased from 67 to 42 percent.

Biologists have not yet studied how this will have other effects. But in any case, the imbalance in basic environmental relationships, in their view, deserves greater attention in various parts of the world.

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