These summary statistics and analyses are based on the European freshwater and terrestrial mollusc dataset published in November 2011.
Overall, about 44% of freshwater molluscs and 20% of the selected terrestrial snails are threatened in Europe, while at the EU 27 level, a slightly higher percentage is observed with 50% of freshwater molluscs and 21% of the selected terrestrial snails facing extinction. A further 9% of freshwater and 15% of the selected terrestrial molluscs are considered Near Threatened. By comparison, of the other groups that been comprehensively assessed in Europe, 37% of freshwater fishes, 23% of amphibians, 19% of reptiles, 15% of mammals and dragonflies, 13% of birds, 9% of butterflies and 7% of aquatic plants are threatened. Additional European Red Lists assessing a selection from species groups have shown that 12% of the crop wild relatives and 11% of the saproxylic beetles are also threatened.
There is a lack of good population trend data and a vast majority of the species have unknown population trends (83% for the freshwater molluscs and more than half (53%) for the terrestrial snails), while, in both cases, less than one percent show an increasing trend.
The main centres of diversity, endemism and threats are found in the Mediterranean, from the Iberian Peninsula to the Balkans, around the Alpine Arc and in various island groups, highlighting the richness, but also the vulnerability of these areas. The Ancient Lakes in the Balkans, the Macaronesian (Azores, Madeira, Canary Islands) and Mediterranean islands deserve a special mention in that regard. For freshwater molluscs the major threats are pollution due to agricultural intensification and urbanisation, and the over-utilisation of water. For terrestrial molluscs the major threats are urbanisation, agriculture and recreational activities.