Bryophytes of a disused China-clay mine: Echassières site in Allier (France) – conservation of an elusive bryoflora

Abstract

Bryophytes of China-clay works have received very little attention in France to date. Repeated bryological surveys were undertaken in a 5-ha disused China-clay mine at Echassières in Allier (central France). The intensive field surveys were conducted on six occasions, in June and August 2018, April and June 2019 and March and September 2020. Sixty-one species (among which 19 liverworts) have been recorded, of which 17 (33% of the total) are considered to be noteworthy species. A remarkable richness of specialized taxa is concentrated within this small area, which acts as a refuge for a rich heterogeneous assemblage of oligotrophic, temperate northern species that is of particularly high conservation value. The bryoflora appears very restricted, across both space and time, hence causing difficulties in surveying and raising special conservation issues. Brachydontium trichodes, Discelium nudum, Endogemma caespiticia and Odontoschisma francisci are amongst the most notable species. The uniqueness and the conservation of the bryophytes are discussed in a larger context, along with a synthesis on bryophytes of China-clay. Management is certainly unavoidable for its preservation and could involve surface-stripping of the substrate to expose new bare areas. The timing of management actions seems to be particularly relevant and should not be based on tracheophyte succession, since pioneer vascular plants flourish in too closed microhabitats, leaving few spaces for bryophytes.

Keywords:

• China-clay
• Discelium nudum
• Endogemma caespiticia
• bryological surveys
• conservation
• stripping

Acknowledgements

Tom Blockeel offered many valuable suggestions to improve this text and is very much thanked for his invaluable help. Four reviewers made interesting remarks that were very appreciated.

Disclosure statement

No potential conflict of interest was reported by the author.