Here we report details of the European research initiative “Soil Crust International” (SCIN) focusing on the biodiversity of biological soil crusts (BSC, composed of bacteria, algae, lichens, and bryophytes) and on functional aspects in their specific environment. Known as the so-called “colored soil lichen community” (Bunte Erdflechtengesellschaft), these BSCs occur all over Europe, extending into subtropical and arid regions. Our goal is to study the uniqueness of these BSCs on the regional scale and investigate how this community can cope with large macroclimatic differences. One of the major aims of this project is to develop biodiversity conservation and sustainable management strategies for European BSCs. To achieve this, we established a latitudinal transect from the Great Alvar of Öland, Sweden in the north over Gössenheim, Central Germany and Hochtor in the Hohe Tauern National Park, Austria down to the badlands of Tabernas, Spain in the south. The transect stretches over 20° latitude and 2,300 m in altitude, including natural (Hochtor, Tabernas) and semi-natural sites that require maintenance such as by grazing activities (Öland, Gössenheim). At all four sites BSC coverage exceeded 30 % of the referring landscape, with the alpine site (Hochtor) reaching the highest cyanobacterial cover and the two semi-natural sites (Öland, Gössenheim) the highest bryophyte cover. Although BSCs of the four European sites share a common set of bacteria, algae (including cyanobacteria) lichens and bryophytes, first results indicate not only climate specific additions of species, but also genetic/phenotypic uniqueness of species between the four sites. While macroclimatic conditions are rather different, microclimatic conditions and partly soil properties seem fairly homogeneous between the four sites, with the exception of water availability. Continuous activity monitoring of photosystem II revealed the BSCs of the Spanish site as the least active in terms of photosynthetic active periods.Electronic supplementary materialThe online version of this article (doi:10.1007/s10531-014-0645-2) contains supplementary material, which is available to authorized users.

The main function of the epidermis is to protect us against a multitude of hostile attacks from the environment. Its main cell type, the keratinocytes have a sophisticated system of different proteins and lipids available to form the cornified envelope, which is responsible for the barrier function of the skin. During ageing, dramatic changes are taking place. Some proteins of the SPRR-, S100- and LCE3-family are massively up-regulated, whereas others like loricrin, filaggrin and the LCE1&2 protein families are significantly down-regulated. The latter ones are known to be under control of calcium and/or 'calcium response elements'. We were able to show that the calcium peak specific for the stratum granulosum, which is the site where loricrin and the LCE1&2 families are synthesized, is reduced during ageing. The resulting cornified envelope in old skin has an extensively changed composition on the molecular level compared to young skin. This knowledge is of critical importance to understand chronic wound formation and ulcers in old age.

Overyielding in mixed‐species forests has been demonstrated in a vast body of literature, and the focus of functional biodiversity research is now shifting towards a mechanistic understanding of these observations. We explored diversity–productivity relationships at two sites of a large‐scale tree diversity experiment, with harsh (Ged) and benign (Zed) environmental conditions for plantation establishment. Additive partitioning methodologies were adopted to detect phenomenological patterns in the productivity data, and the trait structure of mixed communities was used to advance insights into compositional effects. After 6 years of plantation development, biomass productivity was significantly higher in mixtures compared to the monocultures of component species. We observed that processes operated through direct tree–tree interactions, as the diversity signal disappeared where trees in mixed stands were surrounded by conspecific neighbours only. This result is particularly relevant for mixed‐species plantation systems, as trees are commonly planted in monospecific patches to simplify management.Partitioning unveiled strong selection effects at both plantation sites. However, at the harsh Ged‐site this was caused by competitive dominance of species with fast young growth, whereas at the benign Zed‐site, species with slow young growth improved their performances but not at the expense of others (i.e. trait‐dependent complementarity). Species tolerance to shading is an influential trait for predicting biodiversity effects, with community‐weighted means in shade tolerance mediating dominance effects (Ged) and functional diversity in shade tolerance mediating (trait‐dependent) complementarity effects (Zed). Synthesis. This study highlights that biodiversity effects in young tree plantations could be explained by the functional composition of mixed communities, with a key role for species levels of shade tolerance. As contrasting results between plantation sites were observed, future research should target the context‐dependency of diversity–productivity relationships.