Forest elephants help shape Africa’s rainforests

The extinction of forest elephants could result in a reduction in forest biomass leading to a 7% decline in the carbon stocks of central African rainforests, reports a paper in Nature Geoscience. The research suggests that elephants have an important role in shaping the structure of African rainforests.

Forest elephants are found in west and central African forests. Previous research has shown that large herbivores can have important effects on ecosystems, but how elephants affect Africa’s rainforests remains largely unknown.

Fabio Berzaghi and colleagues analysed the effects of elephants on the structure, productivity and carbon storage of African rainforests. They quantify these effects based on field data and model simulations that incorporate elephant disturbance, which they define as the destruction of plants with a stem width of less than 30 cm. The authors find that the reduction of the number of stems in forests due to elephant disturbance leads to changes in the competition for light, water and space among trees. These changes favour the emergence of fewer and larger trees with a higher wood density, which increases the amount of carbon stored. They estimate that at a typical density of 0.5 to 1 animals per km2, elephant disturbance increases the forest biomass by up to 60 tonnes per hectare.