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dc.contributor.authorEloranta, Antti
dc.contributor.authorKahilainen, Kimmo K.
dc.contributor.authorAmundsen, Per-Arne
dc.contributor.authorKnudsen, Rune
dc.contributor.authorHarrod, Chris
dc.contributor.authorJones, Roger I.
dc.date.accessioned2015-04-16T13:22:55Z
dc.date.available2015-04-16T13:22:55Z
dc.date.issued2015-03-23
dc.description.abstractPrey preference of top predators and energy flow across habitat boundaries are of fundamental importance for structure and function of aquatic and terrestrial ecosystems, as they may have strong effects on production, species diversity, and food-web stability. In lakes, littoral and pelagic food-web compartments are typically coupled and controlled by generalist fish top predators. However, the extent and determinants of such coupling remains a topical area of ecological research and is largely unknown in oligotrophic high-latitude lakes. We analyzed food-web structure and resource use by a generalist top predator, the Arctic charr Salvelinus alpinus (L.), in 17 oligotrophic subarctic lakes covering a marked gradient in size (0.5–1084 km2) and fish species richness (2–13 species). We expected top predators to shift from littoral to pelagic energy sources with increasing lake size, as the availability of pelagic prey resources and the competition for littoral prey are both likely to be higher in large lakes with multispecies fish communities. We also expected top predators to occupy a higher trophic position in lakes with greater fish species richness due to potential substitution of intermediate consumers (prey fish) and increased piscivory by top predators. Based on stable carbon and nitrogen isotope analyses, the mean reliance of Arctic charr on littoral energy sources showed a significant negative relationship with lake surface area, whereas the mean trophic position of Arctic charr, reflecting the lake food-chain length, increased with fish species richness. These results were supported by stomach contents data demonstrating a shift of Arctic charr from an invertebrate-dominated diet to piscivory on pelagic fish. Our study highlights that, because they determine the main energy source (littoral vs. pelagic) and the trophic position of generalist top predators, ecosystem size and fish diversity are particularly important factors influencing function and structure of food webs in high-latitude lakes. Benthic, energy mobilization, food-chain length, habitat coupling, lake morphometry, predation, resource competition, stable isotope analysis, trophic nicheen_US
dc.identifier.citationEcology and Evolution (early view)en_US
dc.identifier.cristinIDFRIDAID 1234832
dc.identifier.doi10.1002/ece3.1464
dc.identifier.issn2045-7758
dc.identifier.urihttps://hdl.handle.net/10037/7614
dc.identifier.urnURN:NBN:no-uit_munin_7204
dc.language.isoengen_US
dc.rights.accessRightsopenAccess
dc.subjectVDP::Matematikk og Naturvitenskap: 400::Zoologiske og botaniske fag: 480::Marinbiologi: 497en_US
dc.subjectVDP::Mathematics and natural science: 400::Zoology and botany: 480::Marine biology: 497en_US
dc.titleLake size and fish diversity determine resource use and trophic position of a top predator in high-latitude lakesen_US
dc.typeJournal articleen_US
dc.typeTidsskriftartikkelen_US
dc.typePeer revieweden_US


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