Welcome to the first stage of the 2016 Tour de France and Les Eaux du Tour!
We start out this year in the coastal department of Manche, in the shadow of Mont Saint-Michel. This tidal island is home to a famous monastery and a Ramsar Wetland of International Importance.
The tidal range at Mont Saint-Michel is around 10 meters on average (Lefeuvre et al. 2000). At low tide over 200 square kilometers of tidal flats around the monastery are exposed. In the past, pilgrims would have to walk across the flats to reach the island. Now, a causeway connects the Mont to the mainland, and it was on this causeway that the Tour began this morning.
Fringing the mainland are salt marshes, the grassy plains visible in the image above. These marshes are naturally dominated by Spartina anglica (cordgrass) and Salicornia spp. (samphire or glasswort) in the low marsh, grading into Halimione portulcoides (sea purslane) and Elytrigia atherica (sea couch) at higher elevations. However, these marshes are also heavily grazed by sheep.
The impact of grazing changes the community composition of the marshes to Puccinellia maritima (Guillon 1984). A local culinary specialty, a favorite the Tour announcers every time we ride past Mont Saint-Michel, is agneau de pré-salé, lamb grazed on the marshes.
From Mont Saint-Michel, we continue up the west coast of the Cotentin peninsula. We pass the shellfish port of Granville and the estuary of the Sienne at Havre de Regneville. We turn inland for a while, crossing over the peninsula. Just after the race passes Doville, it very briefly speeds over a set of marshes and bogs that are part of La réserve naturelle nationale des marais de la Sangsurière et de l’Adriennerie which itself is part of a regional natural park and Ramsar site protecting the many wetlands of the Cotentin peninsula. These bogs are home to, among many other species, the southern damselfly (Coenagrion mercuriale).
And of course, we get a thrilling sprint win by Mark Cavendish by Utah Beach! We’ll talk a little more about the hydrodynamics of the English Channel during the stage from Saint-Lô to Cherbourg tomorrow. Stay tuned!
- Lefeuvre, Jean-Claude, Virginie Bouchard, Eric Feunteun, Sonia Grare, Pascal Laffaille, and Alain Radureau. “European salt marshes diversity and functioning: the case study of the Mont Saint-Michel bay, France.” Wetlands Ecology and Management 8, no. 2-3 (2000): 147-161.
- Guillon, Louis-Marie. “Les schorres de la baie du Mont Saint-Michel. Unités de végétation et facteurs du milieu.” (1984).