Abteilung Systemanalyse, Integrated Assessment und Modellierung

Räumliche Dynamik blau-grüner Räuber-Beute-Interaktionen

Interaktionen zwischen terrestrischen räuberischen Vögeln und aquatischen Fischbeutetieren auf verschiedenen räumlichen Ebenen und deren Auswirkungen auf Bewegung, Verhalten und Populationsdynamik

M2E69L201-200R399B417

In diesem Projekt werden die Wechselwirkungen zwischen terrestrischen, räuberischen Vögeln und ihren aquatischen Beutetieren, den Fischen, untersucht. Ziel ist es, den Einfluss abiotischer Variablen und biotischer Interaktionen auf die räumliche Dynamik fischfressender Vögel (wie Graureiher, Ardea cinerea) und der Fischarten, die sie erbeuten (z. B. Forellen), zu untersuchen. Fischfressende Vögel bewegen sich zwischen verschiedenen aquatischen Nahrungsnetzen, und bei einigen ihrer Beutetiere handelt es sich um Wanderfische (z. B. Forelle, Salmo trutta), die sich zwischen Flüssen und Seen bewegen und dabei einen Kompromiss zwischen Wachstumschancen und Prädationsrisiko eingehen. Wir interessieren uns dafür, wie die Fischdichte das Bewegungs- und Nahrungsverhalten von Raubvögeln beeinflusst und wie wiederum der Prädationsdruck durch Vögel das Wanderverhalten und die Populationsdynamik von Fischen beeinflusst. Dieses Projekt integriert also Bewegungs- und Verhaltensökologie mit Räuber-Beute-Interaktionen über die Grenzen von aquatischen und terrestrischen Ökosystemen hinweg.

Der Schwerpunkt liegt auf der Modellierung, wobei wir mehrjährige Datensätze kombinieren über die räumliche Verteilung und Grösse von Vogelkolonien sowie Kamerafallendaten über das Futtersuchverhalten von Vögeln, zusammen mit Datensätzen über den Fischbestand in Fliessgewässern, die Bewegung einzelner markierter Fische und aus Vogelkolonien geborgene Fischmarkierungen.

Interaktionen zwischen terrestrischen räuberischen Vögeln und aquatischen Fischbeutetieren auf verschiedenen räumlichen Ebenen und deren Auswirkungen auf Bewegung, Verhalten und Populationsdynamik

Team

Yannick Burkard Doktorand Tel. +41 58 765 5722 E-Mail senden
Dr. Helen Moor Tel. +41 58 765 6475 E-Mail senden
Dr. Jakob Brodersen Tel. +41 58 765 2204 E-Mail senden

Catherine Graham

Eidg. Forschungsanstalt für Wald , Schnee und Landschaft WSL

Publikationen

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      authors => protected'Lavender, E.; Hunziker, Y.; McLennan, D.; Dermond, P.; S
         talder, D.; Selz, O.; Brodersen, J.' (126 chars)
      title => protected'Sex‐ and length‐dependent variation in migratory propensity in brown tro
         ut' (78 chars)
      journal => protected'Ecology of Freshwater Fish' (26 chars)
      year => protected2023 (integer)
      volume => protected23 (integer)
      issue => protected'1' (1 chars)
      startpage => protected'e12745 (12 pp.)' (15 chars)
      otherpage => protected'' (0 chars)
      categories => protected'migration; passive telemetry; potamodromy; predation-growth trade-off; Salmo
          trutta; sdY gene' (93 chars)
      description => protected'In partially migratory species, individuals either migrate at some point(s) 
         in life or reside within their natal habitat throughout life. For salmonid f
         ish, migration creates opportunities for feeding and growth, but it is also 
         associated with increased mortality risk. Such trade-offs likely differ betw
         een the sexes, since reproductive output is more closely tied to body size i
         n females than males. However, testing hypotheses on sex-specific migratory 
         behaviour in would-be first-time migratory salmonids is difficult, since sex
         es are generally morphologically indistinguishable prior to maturation. Prev
         ious studies have evaluated the influence of sex on migration based on disse
         ction of migratory juveniles or the sex ratio of returning adults. However, 
         both approaches are potentially biased by differential survival during migra
         tion. Here, we utilise advances in minimally invasive genetic sex-determinat
         ion methods for salmonids to investigate sex-specific, spring out-migration 
         propensity in potamodromous brown trout (<em>Salmo trutta</em>) in a pre-Alp
         ine, central European lake. We show that there are marked differences in mig
         ratory behaviour between males and females, with small (~10 cm) females be
         ing approximately twice as likely to migrate out of their natal river in spr
         ing compared to similarly sized males, which generally migrate for the first
          time at larger sizes (in similar proportions to larger females). This study
          highlights how novel genetic sex-determination techniques can provide insig
         ht into the sex- and size-specific life-history trade-offs that shape migrat
         ion propensity. Moving forward, these techniques should become useful tools 
         for ecologists and fisheries managers.' (1710 chars)
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      doi => protected'10.1111/eff.12745' (17 chars)
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Sex‐ and length‐dependent variation in migratory propensity in brown trout

In partially migratory species, individuals either migrate at some point(s) in life or reside within their natal habitat throughout life. For salmonid fish, migration creates opportunities for feeding and growth, but it is also associated with increased mortality risk. Such trade-offs likely differ between the sexes, since reproductive output is more closely tied to body size in females than males. However, testing hypotheses on sex-specific migratory behaviour in would-be first-time migratory salmonids is difficult, since sexes are generally morphologically indistinguishable prior to maturation. Previous studies have evaluated the influence of sex on migration based on dissection of migratory juveniles or the sex ratio of returning adults. However, both approaches are potentially biased by differential survival during migration. Here, we utilise advances in minimally invasive genetic sex-determination methods for salmonids to investigate sex-specific, spring out-migration propensity in potamodromous brown trout (Salmo trutta) in a pre-Alpine, central European lake. We show that there are marked differences in migratory behaviour between males and females, with small (~10 cm) females being approximately twice as likely to migrate out of their natal river in spring compared to similarly sized males, which generally migrate for the first time at larger sizes (in similar proportions to larger females). This study highlights how novel genetic sex-determination techniques can provide insight into the sex- and size-specific life-history trade-offs that shape migration propensity. Moving forward, these techniques should become useful tools for ecologists and fisheries managers.
Lavender, E.; Hunziker, Y.; McLennan, D.; Dermond, P.; Stalder, D.; Selz, O.; Brodersen, J. (2023) Sex‐ and length‐dependent variation in migratory propensity in brown trout, Ecology of Freshwater Fish, 23(1), e12745 (12 pp.), doi:10.1111/eff.12745, Institutional Repository
   

Kontakt

Dr. Helen Moor Tel. +41 58 765 6475 E-Mail senden