Overall, 22.5% of European bryophyte species assessed in this study are considered threatened in Europe, with two species classified as Extinct and six assessed as Regionally Extinct (RE). A further 9.6% (173 species) are considered Near Threatened and 63.5% (1,140 species) are assessed as Least Concern. For 93 species (5.3%), there was insufficient information available to be able to evaluate their risk of extinction and thus they were classified as Data Deficient (DD). When more data become available, some of these species might also prove to be threatened.
Based on other European Red List assessments, 59% of freshwater molluscs, 40% of freshwater fishes, 28% of grasshoppers, crickets and bush-crickets, 23% of amphibians, 20% of reptiles, 20% of ferns and lycopods, 17% of mammals, 16% of dragonflies, 13% of birds, 9% of butterflies and bees, 8% of aquatic plants and 2% of medicinal plants are threatened at the European level. Additional European Red Lists assessing a selection of species showed that 22% of terrestrial molluscs, 16% of crop wild relatives and 18% of saproxylic beetles are also threatened. The findings of this work suggest that bryophytes are the fifth most threatened group of plants assessed so far.
Looking at the population trends of European bryophytes, 17.1% (307 species) of species are thought to be in decline, including 52.8% of threatened species (162 species). The majority of species (59.3%; 1,062 species) are considered to be stable, including 8.3% of threatened species (88 species), and 1.9% (34 species) are increasing, all of which are LC. However, 21.7% of species (389 species) have unknown population trends, with 129 threatened species (33.2%). 94 of the 191 species (49.2%) that are endemic to Europe (i.e., they are found nowhere else in the world) are threatened (Critically Endangered, Endangered or Vulnerable), highlighting the responsibility that European countries have to protect the global populations of these species.
The areas with the highest species richness include central Europe, namely mountainous areas in the Alps, and to some degree in Scandinavia, Scotland, Wales, Pyrenees, and Eastern Europe, including the Carpathians. Species richness gradually declines towards the south and the east of Europe. It is clear that mountainous areas score most highly in terms of species richness. Similarly, there are a high number of threatened species in the Alps, especially in the eastern Alps, followed by other mountainous areas, notably the Carpathians, the eastern Pyrenees and the Scandinavian mountains. This emphasises the importance of mountain habitats for threatened bryophytes and their conservation. The occurrence of Data Deficient (DD) species is often high in mountainous areas, which could be attributed to the fact that they are the most species-rich areas, but could also be because they are usually more remote and difficult to survey than the lowlands. There are also more DD species in relatively under-recorded parts of Europe, such as Romania, than there are in well-recorded areas, such as Britain and Ireland.
The main threats identified were natural system modifications (i.e., dam construction, increases in fire frequency/intensity, and water management/use), climate change (mainly increasing frequency of droughts and temperature extremes), agriculture (including pollution from agricultural effluents) and aquaculture.