Biodiversity puzzle
Isolated, natural spaces cannot function sustainably. Together, they combine in the form of ecological networks, made up of several interlocking continua with their own physical and biological characteristics: continuum of wooded environments, dry environments, wetlands, etc. On the Grand Site, the diversity of landscape entities and environments is a real asset, but it is threatened.
Environments to protect
In France, as in the rest of the world, the biodiversity is now in danger.
The phenomenon of fragmentation of natural environments, a consequence of human activities in the territories, has been identified for around ten years as one of the primary causes of species disappearance.
This awareness leads to reconsidering the management of natural environments from the perspective of ecological networks. No longer focusing on the protection of sites or species taken individually, it is now a question of developing an approach to management global of these environments.
And on the Grand Site?
Starting from the exceptional environments of limestone lawns, it is possible to characterize the ecological continuum of the Grand Site as follows :
- 5 reservoirs of biodiversity cover 120 ah and correspond to the site Natura 2000 “Calcicolous lawns of the Mâconnais”: Mont Sard, Roche de Vergisson, Rock of Solutre, Mont de Pouilly and Mont de Leynes. Within these entities, lawn habitats are in a generally satisfactory state of conservation. However, in certain areas, such as slopes with steep slopes surrounding rocks, these environments are intertwined with shrub thickets, favoring their fragmentation.
- 35 relay sites cover 44 ha. Scattered throughout the territory, these sites are characterized by very fragmentary lawn habitats, mosaic, with shrubby thickets.
Biodiversity reservoirs and relay sites thus only occupy 2% of the surface area of the territory. This figure reflects the fragility of this ecological network whose main compartments are fragmented and isolated within a very impermeable landscape matrix (vine).
Only one connection area functional was identified in the Solutré valley, east of Grange du Bois. Dominated by bocage meadows, associated with a few fragments of lawns, this sector ensures a ecological continuity between Mont de Pouilly and Roche de Solutré.
Different potential connection areas, the functionality of which remains to be confirmed, have been highlighted. In the western part of the territory, these zones are made up of:
- the bocage meadows of the Arlois valley creating a probable connection between Mont de Leynes and Mont de Pouilly;
- bocage meadows and forest edges to the east and north of the Torvon massif forming a probable connection between the Roche de Solutré, the Roche de Vergisson and Mont Sard.
Risks to contain
On the eastern part of the territory, between Les Roches and the Petite Grosne valley, the connection zones are organized in a more complex way around different relay sites, some bocage meadows and forest edges. This sector, largely dominated by vineyards, presents numerous break zones in the lawn continuum. The phenomenon is observed in particular around Mont de Pouilly, with the absence of a relay site and the omnipresence of the vineyard. In this sector, the absence of plant cover natural or semi-natural, such as grassy strips, relict lawns around vineyards, makes the environments impervious to the dispersion and movement of species associated with lawn habitats.
Network functionality lime lawns is therefore very altered on the territory of the Monts du Mâconnais, in particular on the perimeter of the Great Site from France Solutré Pouilly Vergisson. Beyond the reservoirs of biodiversity, sectors with strong ecological issues require particular attention to limit discontinuities and areas of rupture in the continuum: the Solutré valley (Grange du Bois), the Arlois valley, the foothills of the Torvon Massif and the relay sites around the Roche de Solutré and the Roche de Vergisson.