The rivers of Switzerland harbor a unique biodiversity due to its biogeographic location, which includes four of Europe’s major river drainage systems. Yet, as we are only learning about this rich diversity of genotypes, phenotypes and species, it is already being lost at an alarming rate due to anthropogenic impact on the fluvial ecosystems. To achieve effective conservation with finite resources, a large-scale assessment of the present fish biodiversity of rivers across the country is needed. With this project, we aim to assess biodiversity of fish in Swiss fluvial ecosystems at all levels from genes to communities.
In Progetto Fiumi, we have been sampling fish and lower trophic levels (e.g. invertebrates and periphyton) in hundreds of streams across Switzerland from small mountain streams to large lowland rivers. From each individual fish, we extracted data on weight, length and habitat, took pictures for morphological- and color analyses, took fin clips for genetics and tissue samples for isotope analyses. Finally, we preserved fish individually to enable laboratory studies of e.g. stomach content and detailed morphology. Additionally to our database, we have thereby established a reference collection of Swiss river fish from the years 2013-2018.
In the future, the data and the samples will support researchers and practitioners in understanding the underlying mechanisms of natural and anthropogenic influence of river fish biodiversity and ecological functioning. For example, the analyses of collected genetic material will help us to understand the current structure and spatial distribution of diffident significant evolutionary units, cryptic species and distinct populations. This will in turn create a baseline database to put future samples, e.g. from monitoring programs, into perspective.