Lake size and fish diversity determine resource use and trophic position of a top predator in high-latitude lakes
Eloranta, A., Kahilainen, K. K., Amundsen, P.-A., Knudsen, R., Harrod, C., & Jones, R. (2015). Lake size and fish diversity determine resource use and trophic position of a top predator in high-latitude lakes. Ecology and Evolution, 5(8), 1664–1675. https://doi.org/10.1002/ece3.1464
Published inEcology and Evolution
© 2015 The Authors. Ecology and Evolution published by John Wiley & Sons Ltd. This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.
Prey 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. ...
PublisherJohnWiley & Sons Ltd.
Dataset related to the publicationhttps://doi.org/10.5061/dryad.sc59f
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Additional information about fundingThe project was supported by the Finnish Ministry of Agriculture and Forestry, the European Regional Developmental Fund (project A30205), and the Norwegian Research council (project no. 186320/V40, 213610/F20 and 228714/E20), and by personal grants to APE from the Jenny and Antti Wihuri, the Ella and Georg Ehrnrooth and the Ellen and Artturi Nyyssönen Foundation, and to KKK from the Emil Aaltonen Foundation. ...
Except where otherwise noted, this item's license is described as © 2015 The Authors. Ecology and Evolution published by John Wiley & Sons Ltd. This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.