Détail de la référence

Article

Lycaena helle (Denis & Schiffermüller, 1775) dans le Massif central (France) : une analyse écogéographique (Lepidoptera : Lycaenidae)

Auteurs : Bachelard (Philippe) et Descimon (Henri)


Année de publication : 1999
Publication : Linneana Belgica
Volume : 17
Fascicule : 1
Pagination : 23-41


Résumé :

The violet Copper, Lycaena helle, is considered as endangered in France and Europe; it is protected by the Berne convention and the French law. It has a discontinuous distribution of the "glacial relict" type. In France, it is known from the Ardennes, the Vosges, the Jura, the Massif central and the eastern Pyrenees. It is linked to a wetland plant, Polygonum bistorta. In the Massif central, this species colonizes, often in dense populations, the region located between the northern border of the Sancy massif and the southern tip of the Cezallier massif. A small group of colonies is still present in the Madeleine mountains. The other regions of the Massif central are not colonized at present time, although some display apparently suitable habitats. An introduction practised in the Morvan in 1973 gave rise to a population which expanded slowly, overcoming with difficulty watersheds and forested areas. L. helle needs a mosaic of open spaces and woodland which provide habitats both sunny and sheltered from wind, in the presence of dense colonies of its foodplant. Sufficient elevation, a cold, moist climate and no mediterranean influences seem to be prerequisites to the presence of the species. A "suitability index", contrived from the observation of the habitats, appeared to fit satisfactorily with the presence of L. helle in the various regions of the Massif central. Grazing is obviously noxious to this Copper butterfly. The decrease in grazing pressure which is presently observed in some regions of the Massif central is transiently favourable to the spread of the species in wet grassland but, in the long term, land abandonment gives rise to the invasion of open spaces by forest, which obliterates the butterfly habitats. The features of this evolution give to L. helle a value of indicator species in land management