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Over the last 3,800 years, agro-pastoral activities have accelerated alpine soil erosion at a pace four to 10 times faster than their natural formation. The history of this erosion has just been revealed for the first time by a research team led by a CNRS scientist.

The team has shown that high-altitude soil was degraded first, under the combined effect of pastoralism and forest clearing to facilitate the movement of herds. Medium- and low-altitude soil was then eroded with the development of agriculture and new techniques such as the use of plows, from the late Roman period to the contemporary period.

The study has also revealed that the acceleration of soil erosion in mountain environments by human activities did not begin everywhere in the world in synchronous fashion.

This research, which was in the journal Proceedings of the National Academy of Sciences, reinforces the conclusion of a by the authors.

In a global context of soil degradation affecting soil fertility, biodiversity, and water and carbon cycles, the authors are calling for the implementation of global protection measures.

These conclusions were obtained by comparing the isotope signature of lithium in sediments from Lake Bourget with those sampled from the rocks and soil of today. The samples were taken from the largest catchment area in the French Alps.

The data obtained was then compared to that from other regions in the world. The DNA content in the sediments was also studied to identify the mammals and plants present during each period.