The Erve Valley was the first site in Mayenne to commit to the Natura 2000 initiative (network of European natural sites), which demonstrates the clear ecological value of an area. Having become a special conservation area in 2012, this system aims in particular to preserve biological diversity and enhance this natural heritage through the establishment of
management tools (Natura 2000 contracts and agro-environmental measures).
A concentrate of biodiversity
Wildlife
Home to a wonderful variety of animal species, the site is recognized as being of regional interest for the preservation of bats. It is a major site in the department since 17 of the 18 species present in Mayenne have already been recorded there! It also allows you to discover a good number of reptiles and amphibians, insects (such as the Ecaille chinée butterfly or the Agrion de mercure dragonfly), as well as a beautiful diversity of birds.
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Bats
The Saulges caves offer bats large, dark spaces suitable for hanging. The stable temperature and humidity are favorable to species such as the Lesser Horseshoe Bat. The Margot Cave is home to large numbers of hibernating bats (Bechstein's Bat, Greater Horseshoe Bat), and Rochefort is very popular with the Greater Mouse-eared Bat. The Barbastelle Bat only uses the caves during the harshest winters and is content with the cracks near the entrance.
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The Chabot
This small, yellowish fish with brown spots does not exceed 15 cm in length. Its club-shaped head takes up a third of its length, is split by a wide mouth and is followed by two large fan-shaped pectoral fins. Its tiny scales give it a very smooth appearance.
It lives at the bottom of rivers and accompanies wild trout. Little known and rarely fished, the Chabot bears witness, by its presence, to the fish farming value of the Erve and its tributaries.
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The insects
- Agrion of Mercury is a species of dragonfly recognizable by the alternation of blue segments and black patterns.
- The mottled tortoiseshell lives in tall grasses and thistles. The forewings of this curious butterfly are black with yellow stripes, its hindwings are red with large black spots.
- The Great Capricorn is the largest species in its family (Cerambycidae) in France. The larva feeds on dying wood, in which it digs galleries that the adults later use to spend the winter.
And natural habitats
The flora
Saulges is a limestone region open to the Paris Basin and presents an exceptional botanical continuity. The vegetation of a place goes through a succession of evolutionary states that are called vegetation series. Three vegetation series are present within the perimeter of the Natura 2000 site of the Evre Valley: the Atlantic series of the Black Alder, the Atlantic series of the English Oak and Elm bocage and the Late-Mediterranean series of the Downy Oak.
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The Atlantic series of the Black Alder
- Black Alder is a tree found along the edges of watercourses or ponds, in the most humid areas.
- Batrachion fluitantis is a plant community that includes floating or submerged aquatic species requiring a fast current.
- Alnetea glutinosae is a vegetation also present on the major bed of watercourses, on marshy ground, on the edge of springs or seeps.
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The Bocage Atlantic series
This series is the least site-specific because the limestone soils of the Erve valley are less favorable to it.
- Blackthorn, Rosehip, Fragon, Lantana Viburnum and BoxwoodThese species are found in hedgerows and in the driest areas.
- Low-lying, sparse hay meadowsIt is a formation of poor land, intermediate between lawns and meadows, and sometimes by amendments, by grazing or even by mowing remains left on site.
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The Downy Oak Series
- Mosses, lichens et stonecropsThis low vegetation grows on rocky slabs
- Dry grassy lawn on calcareous soils. Its appearance is that of a sparse meadow. It grows in poor and thin soils
- The vegetation of the Common JuniperThis plant grouping comes from the previous formation (dry grass lawn), and is dependent on the abandonment or a reduction of grazing.
- Stable boxwood formations on rocky slopes
