The mass extinction of big animals in the Amazon region 12,000 years ago is behind loss of soil nutrients, Oxford scientists say, warning of further damage if gigantic creatures like elephants disappear.
Thousands of years after human hunters wiped out big land animals like giant ground sloths, the ecosystems they lived in are still feeling the effects, researchers said.
Researchers demonstrated that large animals have acted as carriers of key nutrients to plants and animals over thousands of years and on continental scales.
The study explains that vital nutrients are contained in the dung and bodies of big animals.
As they eat and move more than small animals, they have a particularly important role in transporting nutrients into areas where the soil is otherwise infertile.
Researchers used a new mathematical model to calculate the effect of mass extinctions of big animals around 12,000 years ago, focusing on a case study of the Amazon forest.
They estimate that extinctions back then reduced the dispersal of phosphorus in the Amazon by 98 per cent, with far-reaching environmental consequences that remain to this day.
The model also enabled them to forecast the likely environmental effects of the extinction of large animals currently under threat in Africa and Asian forests.
Up until 12,000 years ago, much of the world looked like an African savannah.