The extent of heathland decline is well documented in countries of the north and west of Europe, not so in southern European countries. In this paper, temporal changes produced in wet heathlands of Erica ciliaris and Erica tetralix in the last 26 years in NW Spain were analysed. Thirteen wet heathlands that had been studied in 1980 were again sampled in 2006. Plant species composition, cover, diversity, surface area occupied and soil pH were analysed in each sampling site. The results obtained showed changes in the management of almost all the sampling sites and in their surrounding area, with an increase in non-traditional practices (afforestation, repeated burning) with respect to 1980, resulting in a general decrease in the surface area occupied by these communities. A decrease of the woody cover and, as a result, an increase in the herbaceous cover was observed. Species richness did not show significant changes, but the identity of the species changed, with 73·9 per cent of the exclusive species of these communities declining or disappearing in favour of non-exclusive species. The pH values remained within the normal ranges for these communities, although a slight decrease was recorded. It was concluded that traditional management (cutting, grazing, sporadic burning) favoured the conservation of these ecosystems, with non-severe effects on the vegetation, and this should be noted by conservation planners. Management of the surrounding area should also be controlled to enhance preservation of these landscapes. Copyright © 2012 John Wiley & Sons, Ltd.