In the savanna, an elephant leaves significant traces for more than eight years after its death.
It is well known that elephants profoundly alter African landscapes. They move branches, feed on trees and dig to find water. But their influence does not end with their lives. Researchers have discovered that vegetation and soils continue to change for years at the site where an elephant died.
Pixabay illustration
The study took place in Kruger National Park, South Africa. Researchers found several sites where elephants had died, some very recently and others long ago. They collected soil samples and observed the plants and animals that visit these places.
At first, vegetation almost completely disappears from a small area. Then, little by little, organic matter from the animal enriches the soil. Analyses reveal amounts of nitrogen sometimes up to 3,000 times higher than in the surrounding ground.
Soil with such high nutrient levels does not immediately become more fertile for plants. On the contrary, certain substances accumulate to levels that slow regrowth. Highly active microbes benefit from these conditions, but only a few species dominate, reducing their diversity.
Elephant bones in the savanna of Kruger National Park, South Africa. Years after the animal's death, decomposition can still alter the soil and vegetation.
Photo: researchers from the University of California, Santa Barbara, published by UCSB News (2021).
Over the months and years, grasses become established and grow in this enriched soil. They contain high levels of nutrients and attract grazing animals, which return to feed in the area.
This activity helps prolong the phenomenon. By coming to feed, herbivores also bring organic matter to the soil. Yet the plants are not necessarily more diverse: some species that grow very quickly occupy almost all the space.
The most surprising aspect is how long this effect lasts. Eight years after an elephant's disappearance, differences remain visible in the composition of the soil, the vegetation and the presence of herbivores. The team does not yet know exactly when the site returns to its original state.
These observations show that a large animal continues to contribute to the balance of its environment long after the end of its life. They also invite us to view the ecological role of elephants differently, including when traces of their presence are no longer visible as such to the naked eye.