Department Fish Ecology and Evolution

Progetto Fiumi

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.

Selected publications

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      authors => protected'Brodersen, J.; Hellmann, J.; Seehausen, O.' (57 chars)
      title => protected'Erhebung der Fischbiodiversität in Schweizer Fliessgewässern. "Progetto Fi
         umi" Schlussbericht' (95 chars)
      journal => protected'' (0 chars)
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      startpage => protected'356 p' (10 chars)
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      description => protected'<em>Die einzigartige Fischvielfalt in Fliessgewässer-Ökosystemen in und um
          die Schweiz</em><br />Aufgrund der geografischen Lage in vier der wichtigst
         en Wassereinzugsgebieten Europas und der grossen Vielfalt an Lebensräumen w
         eisen die aquatischen Ökosysteme der Schweiz eine aussergewöhnlich hohe Fi
         schvielfalt auf. Diese Vielfalt ist hauptsächlich durch zwei verschiedene P
         rozesse entstanden, einerseits durch die Zusammenführung bereits vorhandene
         r Vielfalt, und andererseits durch postglaziale Evolutionsprozesse. Der letz
         
         
         elen verschiedenen Ebenen zu finden. Neben der Artenvielfalt beherbergen die
          verschiedenen Flüsse und Bäche auch eine Vielfalt an diversen Fischgemein
         schaften, wobei sowohl die Unterschiede in der Artenzahl als auch in der Art
         enzusammensetzung zu unterschiedlichen Nahrungsnetzen und Ökosystemprozesse
         n zwischen den Flüssen führen. Viele Fischarten weisen auch ein hohes Mass
          an intraspezifischer Vielfalt auf, z. B. in Bezug auf Morphologie, Physiolo
         gie, Ökologie, Lebensgeschichte und Genom. Diese intraspezifische Vielfalt 
         ist insofern von Bedeutung, dass verschiedene Populationen möglicherweise a
         n unterschiedliche Lebensräume angepasst sind und eine hohe genetische Viel
         falt aufweisen. Letzteres ermöglicht es den einzelnen Individuen innerhalb 
         einer Population, verschiedene Nischen zu besetzen, und es ermöglicht den P
         opulationen, sich besser an veränderte Umweltbedingungen anzupassen. [...]<
         br /><br /><em>The unique fish diversity in riverine ecosystems in and aroun
         d Switzerland</em><br />As a consequence of its geographic location within f
         our of Europe’s major watersheds and a large amount of habitat diversity, 
         aquatic ecosystems in Switzerland harbor an exceptionally high amount of fis
         h diversity. This diversity has mainly been formed by two different processe
         s, i.e. assembly of prev...' (3027 chars)
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      authors => protected'Brodersen,&nbsp;J.; Seehausen,&nbsp;O.' (38 chars)
      title => protected'Why evolutionary biologists should get seriously involved in ecological moni
         toring and applied biodiversity assessment programs' (127 chars)
      journal => protected'Evolutionary Applications' (25 chars)
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      categories => protected'conservation; ecosystem monitoring; evolutionary biology; genotypes; managem
         ent; phenotypes' (91 chars)
      description => protected'While ecological monitoring and biodiversity assessment programs are widely 
         implemented and relatively well developed to survey and monitor the structur
         e and dynamics of populations and communities in many ecosystems, quantitati
         ve assessment and monitoring of genetic and phenotypic diversity that is imp
         ortant to understand evolutionary dynamics is only rarely integrated. As a c
         onsequence, monitoring programs often fail to detect changes in these key co
         mponents of biodiversity until after major loss of diversity has occurred. T
         he extensive efforts in ecological monitoring have generated large data sets
          of unique value to macro-scale and long-term ecological research, but the i
         nsights gained from such data sets could be multiplied by the inclusion of e
         volutionary biological approaches. We argue that the lack of process-based e
         volutionary thinking in ecological monitoring means a significant loss of op
         portunity for research and conservation. Assessment of genetic and phenotypi
         c variation within and between species needs to be fully integrated to safeg
         uard biodiversity and the ecological and evolutionary dynamics in natural ec
         osystems. We illustrate our case with examples from fishes and conclude with
          examples of ongoing monitoring programs and provide suggestions on how to i
         mprove future quantitative diversity surveys.' (1337 chars)
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      doi => protected'10.1111/eva.12215' (17 chars)
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      authors => protected'Dermond,&nbsp;P.; Thomas,&nbsp;S.&nbsp;M.; Brodersen,&nbsp;J.' (61 chars)
      title => protected'Environmental stability increases relative individual specialisation across 
         populations of an aquatic top predator' (114 chars)
      journal => protected'Oikos' (5 chars)
      year => protected2018 (integer)
      volume => protected127 (integer)
      issue => protected'2' (1 chars)
      startpage => protected'297' (3 chars)
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      description => protected'The concept of the niche has long been a central pillar in ecological theory
         , with a traditional focus on quantifying niches at the species or populatio
         n level. However, the importance of individual-level niche variation is incr
         easingly being recognised, with a strong focus on individual specialisation.
          While examples illustrating the contribution of the individual niche to who
         le population niche structure are accumulating rapidly, surprisingly little 
         is known about the conditions that shape the differences between these two p
         otentially divergent components. Though theory predicts that stability shoul
         d influence the extent of such intra-specific specialisation, we know of no 
         previous study that has investigated its role in individual specialisation, 
         and the differentiation between individual- and population niches. Here, we 
         studied the diet of individuals from multiple populations of an aquatic top-
         predator, <i>Salmo trutta</i>, inhabiting contrasting stable, groundwater fe
         d and unstable, surface water fed pre-alpine streams. Based on stomach conte
         nt analysis, we found that individuals living in stable environments display
         ed a higher degree of specialisation than those in unstable environments, wi
         th the between individual component of niche width being approximately twice
          as high in the former. We subsequently validated these results by evidence 
         gained from stable isotope analysis of muscle tissue. As such, we reveal tha
         t environmental stability can signifi cantly infl uence individual niches wi
         thin populations, leading to increased specialisation.' (1574 chars)
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Erhebung der Fischbiodiversität in Schweizer Fliessgewässern. "Progetto Fiumi" Schlussbericht

Die einzigartige Fischvielfalt in Fliessgewässer-Ökosystemen in und um die Schweiz
Aufgrund der geografischen Lage in vier der wichtigsten Wassereinzugsgebieten Europas und der grossen Vielfalt an Lebensräumen weisen die aquatischen Ökosysteme der Schweiz eine aussergewöhnlich hohe Fischvielfalt auf. Diese Vielfalt ist hauptsächlich durch zwei verschiedene Prozesse entstanden, einerseits durch die Zusammenführung bereits vorhandener Vielfalt, und andererseits durch postglaziale Evolutionsprozesse. Der letztgenannte Prozess hat zu einem hohen Grad an Endemismus vor allem in den grösseren Seen des Alpenraums geführt. Diese einzigartige Vielfalt ist auf vielen verschiedenen Ebenen zu finden. Neben der Artenvielfalt beherbergen die verschiedenen Flüsse und Bäche auch eine Vielfalt an diversen Fischgemeinschaften, wobei sowohl die Unterschiede in der Artenzahl als auch in der Artenzusammensetzung zu unterschiedlichen Nahrungsnetzen und Ökosystemprozessen zwischen den Flüssen führen. Viele Fischarten weisen auch ein hohes Mass an intraspezifischer Vielfalt auf, z. B. in Bezug auf Morphologie, Physiologie, Ökologie, Lebensgeschichte und Genom. Diese intraspezifische Vielfalt ist insofern von Bedeutung, dass verschiedene Populationen möglicherweise an unterschiedliche Lebensräume angepasst sind und eine hohe genetische Vielfalt aufweisen. Letzteres ermöglicht es den einzelnen Individuen innerhalb einer Population, verschiedene Nischen zu besetzen, und es ermöglicht den Populationen, sich besser an veränderte Umweltbedingungen anzupassen. [...]

The unique fish diversity in riverine ecosystems in and around Switzerland
As a consequence of its geographic location within four of Europe’s major watersheds and a large amount of habitat diversity, aquatic ecosystems in Switzerland harbor an exceptionally high amount of fish diversity. This diversity has mainly been formed by two different processes, i.e. assembly of previously existing diversity and postglacial evolutionary processes. The latter of these processes has led to a high degree of endemism in especially the larger lakes in the Alpine region. The unique diversity can be found on many different levels. Besides the diversity of species, the different rivers and streams also harbor a diversity of fish communities, where both the variation in the number of species and the composition of species result in different food webs and ecosystem processes between rivers. Many of the fish species also show a high degree of intraspecific diversity in e.g. morphology, physiology, ecology, life history and in their genome. This intraspecific diversity is important in terms of different populations potentially being adapted to different habitats and in terms of populations harboring a high genetic diversity. The latter makes the individual fish within a population able to occupy different niches and makes the populations better able to adapt to changing environmental conditions. [...]
Brodersen, J.; Hellmann, J.; Seehausen, O. (2023) Erhebung der Fischbiodiversität in Schweizer Fliessgewässern. "Progetto Fiumi" Schlussbericht, 356 p, doi:10.55408/eawag:30020, Institutional Repository

Why evolutionary biologists should get seriously involved in ecological monitoring and applied biodiversity assessment programs

While ecological monitoring and biodiversity assessment programs are widely implemented and relatively well developed to survey and monitor the structure and dynamics of populations and communities in many ecosystems, quantitative assessment and monitoring of genetic and phenotypic diversity that is important to understand evolutionary dynamics is only rarely integrated. As a consequence, monitoring programs often fail to detect changes in these key components of biodiversity until after major loss of diversity has occurred. The extensive efforts in ecological monitoring have generated large data sets of unique value to macro-scale and long-term ecological research, but the insights gained from such data sets could be multiplied by the inclusion of evolutionary biological approaches. We argue that the lack of process-based evolutionary thinking in ecological monitoring means a significant loss of opportunity for research and conservation. Assessment of genetic and phenotypic variation within and between species needs to be fully integrated to safeguard biodiversity and the ecological and evolutionary dynamics in natural ecosystems. We illustrate our case with examples from fishes and conclude with examples of ongoing monitoring programs and provide suggestions on how to improve future quantitative diversity surveys.
Brodersen, J.; Seehausen, O. (2014) Why evolutionary biologists should get seriously involved in ecological monitoring and applied biodiversity assessment programs, Evolutionary Applications, 7(9), 968-983, doi:10.1111/eva.12215, Institutional Repository

Environmental stability increases relative individual specialisation across populations of an aquatic top predator

The concept of the niche has long been a central pillar in ecological theory, with a traditional focus on quantifying niches at the species or population level. However, the importance of individual-level niche variation is increasingly being recognised, with a strong focus on individual specialisation. While examples illustrating the contribution of the individual niche to whole population niche structure are accumulating rapidly, surprisingly little is known about the conditions that shape the differences between these two potentially divergent components. Though theory predicts that stability should influence the extent of such intra-specific specialisation, we know of no previous study that has investigated its role in individual specialisation, and the differentiation between individual- and population niches. Here, we studied the diet of individuals from multiple populations of an aquatic top-predator, Salmo trutta, inhabiting contrasting stable, groundwater fed and unstable, surface water fed pre-alpine streams. Based on stomach content analysis, we found that individuals living in stable environments displayed a higher degree of specialisation than those in unstable environments, with the between individual component of niche width being approximately twice as high in the former. We subsequently validated these results by evidence gained from stable isotope analysis of muscle tissue. As such, we reveal that environmental stability can signifi cantly infl uence individual niches within populations, leading to increased specialisation.
Dermond, P.; Thomas, S. M.; Brodersen, J. (2018) Environmental stability increases relative individual specialisation across populations of an aquatic top predator, Oikos, 127(2), 297-305, doi:10.1111/oik.04578, Institutional Repository

Contact

Dr. Jakob Brodersen Tel. +41 58 765 2204 Send Mail

Funding and Duration

Funding:    BAFU

Duration:   2013 - 2015

News

Chubs (Squalius cephalus), also called European chub, on their spawning ground in the Trême, a tributary of the Saane, Canton Fribourg, Switzerland. (Photo: Michel Roggo)

March 28, 2023

Fish diversity documented in Switzerland’s rivers