New ecological and distributional data on Lewinskya shawii in France and its conservation in anthropogenic environments

Abstract

Hugonnot, V. 2019. New ecological and distributional data on Lewinskya shawii in France and its conservation in anthropogenic environments – Herzogia 33: 188 –206.Lewinskya shawii is a southern and Central European and Mediterranean species occurring disjunctly in western North America. It has large populations in the Massif Central and Auvergne region, France, where numerous new localities are herein reported. Its national distribution in France is therefore updated. The ecology of the species was studied by analysing recent releves performed on a variety of phorophytes, mostly ash (Fraxinus excelsior) and beech (Fagus sylvatica). Lewinskya shawii occurs in urban and non-urban habitats, but to a large extent on well-illuminated trees in the open countryside, where it can be associated with rich epiphytic assemblages. Such trees are mostly pollards with Orthotricha growing abundantly on the trunk. In Auvergne, the anthropogenic environment is considered to be favourable to epiphytic Orthotricha s.l. It is suggested that light is a key factor for epiphytic assemblages in urban environments. Preliminary recommendations for the conservation of Lewinskya shawii and associated Red-Listed bryophytes in the small towns of Auvergne are given. Traditional management activities are considered capable of maintaining highly diverse epiphytic assemblages.