Changing status of Calystegia soldanella (Sea Bindweed; Convolvulaceae) on the Sefton Coast, North Merseyside, UK

The results of a survey of the Red-listed Calystegia soldanella in summer 2024 on the Sefton Coast, north Merseyside, UK, were compared with those from a similar study in 2010. Fourteen years on, the six patches recorded in 2010 were still extant, all but one having increased in area. Two new patches were discovered and the total area occupied by the plant increased by 90%. With the exception of one patch on a concrete seawall, all were on calcareous sand-dunes, with a mean distance of 70 m from the shore. The number of associated vascular taxa increased from 33 in 2010 to 66 in 2024. Main plant communities changed from fixed-dune to dune grassland, the latter characterised by the appearance of much Arrhenatherum elatius, not found in 2010. Although C. soldanella appears to show resilience to habitat change, apparent threats to Sefton Coast populations include coastal erosion, a trend towards taller, coarser vegetation, together with scrub formation and loss of bare sand. Possible conservation measures are discussed.