Two decades of dune slack restoration in North Wales: Diversity,
Community and Habitat Specialists
Abstract
Humid dunes slacks are a highly threatened habitat, listed as vulnerable
in the EU habitat red list. Accelerated successional processes in dune
systems have resulted in the loss and degradation of ideal conditions
for specialist dune slack species, hence the need for conservation
management. This study investigated the restoration of a dune slack in
North Wales, UK, where soil removal was undertaken to reinstate
nutrient-poor open damp conditions. It assessed the outcomes of the
management for dune slack communities over the 18 years since
restoration. It also assessed the differences between restored and
unrestored areas of dune slacks. Since the restoration was carried out
in winter 2004/05 surveys of fixed quadrats were undertaken most years
until 2022 with an additional survey in 2022 of the adjacent un-restored
parts of the dune slacks. Species diversity and plant community
composition changes over time were assessed using multivariate analysis
and indicator species analysis. Comparisons between the restored and
unrestored areas of the dune slacks were also made. Ellenberg Indicator
Values (EIVs) were examined to identify potential environmental drivers
of post management successional changes. After 18 years a species rich
and diverse dune slack community exists. This is absent from the
unrestored area. The establishment of species occurred rapidly in the
first three years, followed by continued but slower increases in species
richness and diversity. This is due to the addition of new species
without losses of established species. EIVs show no significant
difference over time suggesting the restored areas are still at an early
stage of succession. Distinct stages of community change since
restoration are characterised by different indicator species. Plants are
likely to be largely recruited from an existing seed bank. Restoration
by turf removal may be suitable for other low nutrient, species rich
habitats dependent upon fluctuating groundwater levels.