Role of predation in biological communities in naturally eutrophic sub-Arctic Lake Myvatn, Iceland

Effects of fish predation on consumers tend to be particularly strong in oligotrophic Arctic and sub-Arctic lakes. However, it remains unclear whether the fish influence the trophic structure and dynamics of naturally eutrophic lakes in these cold environments with simple food web structures. To stu...

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Bibliographic Details
Published in:Hydrobiologia
Main Authors: Canedo-Argueles, Miguel, Sgarzi, Serena, Arranz, Ignasi, Quintana, Xavier D., Ersoy, Zeynep, Landkildehus, Frank, Lauridsen, Torben L., Jeppesen, Erik, Brucet, Sandra
Format: Article in Journal/Newspaper
Language:English
Published: 2017
Subjects:
Arctic lakes
Trophic cascade
Predator control
Resource control
Anabaena
Fish predation
Climate change
SALVELINUS-ALPINUS
RIVER LAXA
BODY-SIZE
FISH
PHYTOPLANKTON
ZOOPLANKTON
PLANKTON
WATERS
FOOD
FLUCTUATIONS
Arctic
Arctic Lake
Laxa
Vatn
Iceland
Phytoplankton
Salvelinus alpinus
Zooplankton
Online Access:https://pure.au.dk/portal/en/publications/78a68a5f-6ec1-47f4-b0b2-b390f5250a4d
https://doi.org/10.1007/s10750-016-3031-0
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Summary:Effects of fish predation on consumers tend to be particularly strong in oligotrophic Arctic and sub-Arctic lakes. However, it remains unclear whether the fish influence the trophic structure and dynamics of naturally eutrophic lakes in these cold environments with simple food web structures. To study this, we conducted a 3-month in situ-controlled experiment in sub-Arctic Lake MA 1/2 vatn, Iceland. We used the planktivorous fish three-spined sticklebacks (Gasterosteus aculeatus) as the main top predator. The cladocerans Eurycercus lamellatus and Acroperus harpae were significantly associated with fishless enclosures, whereas the rotifers Polyarthra sp. and Filinia terminalis were significantly associated with the fish enclosures. Fish predation led to a significant increase in phytoplankton biomass and a reduction in the zooplankton:phytoplankton biomass ratio, the mean zooplankton length and cladoceran mean biomass. Fish effects might have been stronger if a bloom of Anabaena in August had not overridden potential cascading effects. We argue that both top-down and bottom-up forces are important for structuring the communities in the lake. Our results suggest that Arctic and sub-Arctic lakes may undergo important changes in trophic dynamics if they get warmer and more nutrient rich as expected with the global climate change.

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