A new vascular plant Red List for Great Britain.

This report presents a comprehensive revision of the Great Britain (GB) Red List for all native and archaeophyte vascular plants, utilising verified datasets published by the Botanical Society of Britain and Ireland (BSBI) covering three distribution atlas time periods (1930-1969; 1987-1999; 2000-2019). Assessments of threat were undertaken using the latest International Union for Conservation of Nature (IUCN) Guidelines and Criteria. Of 1720 taxa evaluated, 434 (25%) were assessed as Critically Endangered (55), Endangered (117) or Vulnerable (262). A further 22 taxa were assessed as Regionally Extinct, and 140 as Near Threatened. Factors associated with threat included rarity, the intensification of management, long-term neglect, development, eutrophication and pollution. Such factors have had a disproportionate impact on the flora of lowland regions. An elevated threat status for numerous historically widespread ‘positive indicator’ taxa of semi-improved terrestrial habitats, and those of wetland and aquatic habitats, was associated with the degradation or destruction, and increased fragmentation, of suitable habitat, with such taxa increasingly confined to protected refugia. For a small number of montane plants present at their absolute southern European range limits in GB, threat was also linked to the symptoms of climate change.