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A high diversity of Apicomplexa was recently found in tropical soils presumably reflecting the diversity of their invertebrate hosts, but such patterns have not been explored in colder regions. We analysed the diversity of Apicomplexa and their potential metazoan hosts in litter and mosses collected in 11 different alpine habitats using an eDNA metabarcoding approach. The abundance and diversity of Apicomplexa phylotypes and of their potential invertebrate hosts were positively correlated. This confirms that eDNA metabarcoding is a useful tool to explore the unknown biodiversity of free-living eukaryotes, as well as potential host-parasite interactions. Future studies should aim at describing this diversity using a combination of morphological and molecular approaches.

Research in warm-climate biomes has shown that invasion by symbiotic dinitrogen (N2)-fixing plants can transform ecosystems in ways analogous to the transformations observed as a consequence of anthropogenic, atmospheric nitrogen (N) deposition: declines in biodiversity, soil acidification, and alterations to carbon and nutrient cycling, including increased N losses through nitrate leaching and emissions of the powerful greenhouse gas nitrous oxide (N2O). Here, we used literature review and case study approaches to assess the evidence for similar transformations in cold-climate ecosystems of the boreal, subarctic and upper montane-temperate life zones. Our assessment focuses on the plant genera Lupinus and Alnus, which have become invasive largely as a consequence of deliberate introductions and/or reduced land management. These cold biomes are commonly located in remote areas with low anthropogenic N inputs, and the environmental impacts of N2-fixer invasion appear to be as severe as those from anthropogenic N deposition in highly N polluted areas. Hence, inputs of N from N2 fixation can affect ecosystems as dramatically or even more strongly than N inputs from atmospheric deposition, and biomes in cold climates represent no exception with regard to the risk of being invaded by N2-fixing species. In particular, the cold biomes studied here show both a strong potential to be transformed by N2-fixing plants and a rapid subsequent saturation in the ecosystem's capacity to retain N. Therefore, analogous to increases in N deposition, N2-fixing plant invasions must be deemed significant threats to biodiversity and to environmental quality.

Reduction in land use and complete land abandonment are widespread in mountainous regions and are mainly driven by socio-economic factors. Following land-use decline, shrubs and trees expand rapidly into montane and subalpine grassland and alter ecosystem properties at a large scale. In particular, the N2-fixing shrub Alnus viridis is currently spreading at a breath-taking speed and thereby reduces biodiversity, leads to substantial reactive nitrogen enrichment and suppresses species succession towards coniferous forests across large areas in the Alps. In addition, this shrub vegetation neither protects against avalanches nor does it secure slopes from erosion. The expanding, monotonous A. viridis shrubland is impenetrable for hikers and diminishes scenic beauty and touristic value of the landscape. Actions and management adaptations are needed to halt the expansion of A. viridis. Goats and the traditional sheep breed Engadine sheep proved to be very effective in preventing and reverting shrub expansion because of their specific browsing behaviour.

Schmetterlinge bilden mit über 150 000 Arten eine der grössten Insektenordnungen der Welt. In der Schweiz kommen rund 3700 Arten vor, davon sind 182 Arten echte Tagfalter. Wir konnten auf der Furka in kurzer Zeit 27 Tagfalterarten (15%) und 77 nachtaktive Arten feststellen. Zudem wurden 22 Kleinschmetterlingsarten beobachtet.

Die Gewässer zwischen Gletschereis und Bergbächen sind zwar meist eisig kalt, die Lebensbedingungen sind aber für Gewässerbewohner gleichförmiger als für Landorganismen. Während der vier Feldtage fanden wir rund 90 Kleintierarten und 215 Arten von Kieselalgen. Diese widerspiegeln die kleinräumige Vielfalt der unterschiedlichen Gewässertypen. Bei den artenreichen Köcherfliegen wurde die Larve einer Art gefunden, die bisher nur als erwachsenes Tier bekannt war. Bei den Kieselalgen gelangen zwei Erstnachweise für die Schweiz.