Long-term (37 year) changes in coastal dune slack plant communities

•Questions: How did α-, β- and γ- plant diversity of coastal dune slack plant communities change over 37 years during a period of significant changes in conservation management practices? •Location: Ainsdale Sand Dunes National Nature Reserve, England. Methods We surveyed plant communities in dune slacks at Ainsdale Sand Dunes National Nature Reserve at two time points: in 1985 and in 2022. This period represents a time of significant change involving the introduction of conservation grazing in the context of declining natural rabbit populations and a changing environment. •Results: We show that over 37 years, α-diversity remained relatively stable, but γ-diversity increased, and β-diversity indicated shifts in community structure. Specifically, across the open dunes we observed a decline in positive dune slack indicator species (i.e., of conservation interest), an increase in Salix repens (frequency, cover and height) and a shift towards shade-tolerant and nitrogen-loving plants (as evidenced by Ellenberg values). •Conclusions: These findings suggest that despite the introduction of a conservation grazing programme, current grazing patterns (both wild and livestock) may not provide the level of disturbance required to maintain the open habitats and plant communities typical of healthy dune slacks.