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Bryophytes are important elements of plant communities in most habitat types worldwide. However, due to their relatively small size and difficult identification, bryophyte data are missing in many plant community studies. The objective of the present study is to increase the knowledge about EU Habitat directive bryophyte species distribution and conservation in Latvia. We compiled data from the Natural Data Management System OZOLS database about four EU Habitat Directive bryophyte species: Buxbaumia viridis, Dicranum viride, Hamatocaulis vernicosus and H. lapponicus, all indicators of high–value habitats in Latvia. The most common EU Habitat Directive species in this group was Buxmaumia viridis, which showed a significantly higher occurrence in the Western taiga habitat. Most of Hamatocaulis lapponicus and H. vernicosus localities were registered in protected areas with a high and moderate degree of protection. Most of Buxbaumia viridis and Dicranum viride localities were registered outside of the protected areas with a low degree of protection. Our results showed that EU Habitat Directive bryophyte species conservation in the long–term in Latvia is unclear, especially for B. viridis and D. viride populations. In future studies, we recommend initiating large-scale protected bryophyte monitoring programs and population studies that could contribute to plant community and global climate change research. [ABSTRACT FROM AUTHOR]

The geographical distributions of the two cryptic species of the wetland moss Hamatocaulis vernicosus were mapped for western, central and northern Europe, based on identifications of the two by the nuclear ITS1 + 2 and the plastid rpl16 and trnL–trnF. The distributions of the two cryptic species overlap to a large extent. However, in the west and south-west only cryptic species 1 is present, whereas in the boreal north only cryptic species 2 occurs, which agrees with its distribution in Scandinavia. Despite these differences in distribution, no differences between the two cryptic species were revealed in habitat water chemistry, elevation distribution or climatic niches. The difference in distribution therefore suggests that cryptic species 1 could have survived the glacial period in southern Europe and cryptic species 2 in northern or eastern Europe. However, the studied molecular markers did not reveal geographical patterns suggesting origins in different glacial refugia. Although populations of both cryptic species have decreased in large portions of western Europe, a significantly negative Tajima's D may reflect the long-term expansion south of Scandinavia since the glacial bottleneck, potentially correlated with the expansion of earlier extensive agricultural management of wetlands. [ABSTRACT FROM AUTHOR]

To combat biodiversity loss, the European Union (EU) established a network of protected areas to be implemented by 2000, termed Natura 2000 (N2000). However, several N2000 sites remain unmapped, and various habitats remain undefined. Delayed implementation allows continued habitat degradation and biodiversity loss. Targeting biogenic reefs by blue mussels (Mytilus edulis and Mytilus trossulus), this study 1) compared blue mussel reef definitions across EU member states surrounding the North Sea and Baltic Sea, 2) scrutinized biological mechanisms underpinning the habitat definitions, and 3) provided suggestions for harmonized habitat definitions, respecting spatial and biological variation. By comparing official definitions of blue mussel reefs applied in Denmark, Sweden, The United Kingdom, and Germany, this study revealed A) decadal delay in implementation, B) reef definitions varying significantly regarding number of parameters used for identification (e.g., mussel seabed area (m2), and proportion seabed mussel coverage (%)) and the associated parameter limits (e.g., 2.500 m2, and 30%, respectively). Specifically, parameter limits for identification of reefs range between 1 and 10,000 m2 for mussel area and between 5% and 30% seabed mussel coverage. The study failed to identify biological mechanisms justifying this variation. Variable habitat definitions, unjustified by biological and spatial variation, may result in uneven protection levels across borders, potentially compromising connectivity of the N2000 network. To avoid this scenario, our study highlights the need for compatible biogenic reef definitions reflecting spatial and biological properties and suggests moving from protection of individual reefs to protection of areas where habitat forming blue mussels are regularly occurring. • First trans-national comparison of EU Habitat Directive habitat type definitions. • Evaluating the environmental bases for marine habitat type definitions. • Study reveals significant differences in habitat definition between countries. • Environmental bases unable to explain definition differences. • Reappraisal of marine habitat identification and protection is proposed. [ABSTRACT FROM AUTHOR]