A new IUCN Red List of the bryophytes of Britain, 2023

ABSTRACT

Introduction

Britain supports one of the richest bryophyte floras in Europe. Following previous assessments in 2001 and 2011, the aim of this study was to provide a new IUCN Red List of the bryophytes of Britain.

Methods

Following IUCN guidance, all species known to have occurred in Britain since ad 1500 (n = 1097) were assessed based on a comprehensive review and synthesis of available information. Various new measures are provided here for all species, such as the number of subpopulations, area of occupancy, and extent of occurrence, in addition to national population estimates for 181 species. Results are compared with the previous Red List assessment of 2011.

Key results and conclusions

Species were categorised as Regionally Extinct (RE, n = 4), Not Applicable (NA, n = 23), Data Deficient (DD, n = 45), Critically Endangered (CR, n = 59), Endangered (EN, n = 52), Vulnerable (VU, n = 80), Near Threatened (n = 39) or Least Concern (n = 795). Excluding those in DD, NA or RE, 19% (n = 191) of bryophyte species in Britain are threatened with extinction (i.e. are in CR, EN or VU). Of the 59 species in the highest extinction risk category (CR), it is possible that 20 (34%) are already extinct. Of the 143 species included in the previous assessment in a threatened category (CR, EN or VU), 85 (69%) have been transferred to a new category, mainly because of new information on the status of the species.

KEYWORDS:

• Extinction risk
• hornworts
• liverworts
• mosses
• threatened species

Acknowledgements

Many thanks to Nick Hodgetts for many helpful contributions and useful advice, and for being an important part of the project during the early stages. Thanks also to Mark Hill for very kindly carrying out the Frescalo analysis. Many other people provided generous help and unpublished information, in particular including Tom Blockeel (Sheffield, UK), Sam Bosanquet (Natural Resources Wales), Heinjo During (Driebergen, The Netherlands), Bryan Edwards (Dorset Environmental Records Centre), David Genney (NatureScot), Steven Heathcoat (Goole, UK), Sean O’Leary (Wallingford, UK), Tom Ottley (Goginan, UK), Oliver Pescott (Biological Records Centre Wallingford), Gordon Rothero (Dunoon, UK), Henk Siebel (Natuurmonumenten), Matt Sutton (Wyndrush Wild Ecology) and Stewart Taylor (Nethybridge, UK). Thanks also to Jonathan Cox (Natural England) for managing the study contract, and to Andy Brown (Natural England) and Anthony Maddock (Joint Nature Conservation Committee) for helpful comments.

Disclosure statement

No potential conflicts of interest were reported by the author.

Additional information

Funding

Funding for this work was provided by Natural England.

Notes on contributors

Des A. Callaghan

Des A. Callaghan is a consultant bryologist operating under Bryophyte Surveys Ltd, working throughout Britain and further afield. His research is focused on threatened species, taxonomy and conservation ecology.