European Researchers' Night in Faverges-Seythenex

Lakes are traps for particles that sediment over time. These particles may come from the lake itself, its watershed or the atmosphere. For those who know how to read this archive, a wealth of information about past environments, climates or human activities can be extracted.

Two obvious landscape features are vegetation cover and topography. Since the retreat of the glaciers at the beginning of the Holocene, some 11500 years ago, vegetation has changed considerably in response to climate change and the development of human societies and activities. During this period, erosion was the main process that shaped the topography. It has also changed considerably under the influence of the same factors and the evolution of vegetation cover.

How can the history of vegetation and erosion be traced by studying lake sediments? What do we know of this history in the Northern French Alps today?

Both researchers at the CNRS EDYTEM laboratory, they are studying past environments, in particular landscapes since the end of the last ice age. To do this, they take lake or peatland sediments and analyze them, each with their own method. Charline uses sedimentology/geochemistry to understand sedimentation processes and erosion dynamics, and also analyzes the DNA of plants and animals present in the sediments. Erwan analyzes changes in vegetation through the identification of pollen grains or other plant remains. Their approaches are highly complementary. Their preferred fields are the Alps, but Erwan also works in the Caucasus.

Faverges lies at the foot of mountain ranges with highly distinctive landscapes, due in particular to the omnipresence of highly soluble limestone rocks that chemical erosion sculpts on the surface and tars at depth. These phenomena give rise to arid lapiaz landscapes on the surface and subterranean landscapes visible to speleologists in the thousands of caverns dug by water seeping into the rock. The academics and the evolution of the karst landscape involve several time scales: the long time of geology (that of tens of millennia and millions of years) and human time (that of centuries and decades). Although changes in the karst landscape are often imperceptible, if you look closely enough, you'll already notice that the landscape of our limestone mountains in the Bauges is changing rapidly over several generations, under the combined effect of human activity and climate change. Using the Massif des Bauges as an example, this lecture will provide the keys to understanding and respecting the different facets, visible and invisible, of these endearing and mysterious landscapes, which are less static than they appear.

Fabien Hobléa is a geographer and teacher-researcher in geomorphology and speleo-karstology at the EDYTEM laboratory atUniversité Savoie Mont Blanc. He has studied caves in the Savoie region (Bauges, Chartreuse...) and has been caving with the Savoie Speleo-club since 1984. He has taken part in a number of geographical and speleological exploration expeditions to remote karsts in warm regions (Papua New Guinea, Mexico, Indonesia) and colder regions (Siberia, Chilean Patagonia). He is a long-standing member of the scientific councils of the Chartreuse High Plateaux Regional Nature Park and Nature Reserve, the Bauges Massif Regional Nature Park and UNESCO World Geopark, and the Chablais Geopark, all of which contain glaciers that are being studied to measure the effects of global warming.

The use of mountain slopes for tourism, through leisure, wellness and touring activities, is leading to changes in the landscape. Not only the number of visitors, but also the development of tourist sites are helping to shape a mountain landscape that has never been seen before, even though it is sold as "authentic". Thus, the typical mountain panorama perceived by tourists is the result of decades of tourism, which has resulted in the invisibility of part of the mountain heritage that predates the major development of the slopes.

Yoann Collange has been a doctoral student in heritage geography since 2020, following bi-disciplinary studies in history and geography. His thesis studies the place occupied today by archaeological heritage, particularly rock carvings, in the French and Italian Alpine high valleys. These engraved rocks, which are perceived differently from one valley to the next, sometimes play a central role in local tourism policies. At other times, they are unevenly known by the local population, and are not the subject of any political discourse or associative interest.

In France, there are still many "communal" and "sectional" assets in the form of ancestral collective or shared properties. Social institutions that manage natural resources prudently by the populations themselves, these collective properties are making a resurgence after having been undervalued by a national law focused on individual and exclusive private property since the French Revolution and the advent of the Civil Code in 1804. AtUniversité Savoie Mont Blanc, a team of legal experts, sociologists and historians have been working together since 2018 with the local populations involved on several sites both abroad and in France (particularly south of Lake Annecy, where several remarkable examples of common land ownership have shaped the landscape). 

Co-directed by Jean-François Joye, jurist, with Olivier Chavanon, sociologist (Centre de recherche en Droit Antoine Favre and Pôle "Enquête" de l'Université Savoie Mont Blanc), this scientific project focuses on the contribution of the land commons to local territories, with a view to sober resource management and social cohesion in the 21st century.