Abstract The Picos de Europa are a range of predominantly Carboniferous Limestone and Sandstone mountains mainly in the Cantabrian region of northern Spain. The highest peaks are precipitous and reach 2600m. There are complex gradients between Lusitanian, Alpine and Mediterranean environmental zones, as well as variable soil types. In combination with the long history of traditional agricultural management, a wide range of diverse habitats and species is present. The herb-rich hay meadows have long been recognised as having a high nature conservation value but, as elsewhere in European mountains, such grasslands are threatened by changing agricultural practices. Accordingly, in 1993, 92 quadrats were recorded using a restricted list of indicator species from stratified random samples. The authors repeated the sample in 2009. Changed land use had only occurred in approximately 3% of meadows, however, farmyard manure was no longer used, probably because of shortage of labour. Statistical analysis of the vegetation data showed a range of significant changes consistent with the increased use of slurry, as well as re-seeding of some fields. The grass swards had not only become denser, with fewer species present, but there was also a loss of sensitive indicators especially of calcareous conditions and open vegetation. By contrast, competitors had increased and the vegetation had become simpler, with the balance of vegetation types shifting to more nutrient rich conditions. These changes have mainly occurred in the more fertile meadows used for silage. The core of about 35% of herb-rich meadows, mainly cut for hay, has remained relatively stable but the results show that they are at risk if the current trend continues. If management practices that form the core of traditional agriculture are not maintained, one of the most important resources of herb-rich meadows in Europe will be lost.