Distribution and ecology of Equisetum variegatum (Variegated Horsetail) (Equisetaceae) on the Sefton Coast sand-dunes, north Merseyside, UK

Abstract

A 2022 survey of Equisetum variegatum Schleich. Ex F. Weber & D. Mohr (Equisetaceae) (Variegated Horsetail) on the Sefton Coast sand-dunes, north Merseyside, found the plant in 19 of 28 known sites for the species. Most extant localities were in relatively young, calcareous dune-slacks and scrapes with short vegetation close to the shore, having ground-water-gley or peaty-gley soils with a high pH. Quadrats in vegetation supporting E. variegatum had a total of 78 vascular taxa, 20 of them being regionally or nationally notable and 10 Red-listed. There were only four non-native species. TABLEFIT analysis found that five UK National Vegetation Classification (NVC) dune-slack communities were represented, the most frequent being SD15: Salix repens-Calliergon cuspidatum dune-slack, followed by SD16: Salix repens-Holcus lanatus dune-slack. However, statistical fits to recognised NVC vegetation types were often poor. Loss of E. variegatum from nine sites was considered to be due to overgrowth by coarse vegetation and scrub, while 11 sites appeared to be imminently threatened by scrub development. Management practices that could assist conservation of E. variegatum and other notable plants in the Sefton dunes are discussed.