Disentangling trophic relationships in a High Arctic tundra ecosystem through food web modeling

P Legagneux, Gilles Gauthier, D Berteaux, J Bety, M-C Cadieux, Frederic Bilodeau, E Bolduc, L McKinnon, A Tarroux, J-F Therrien, L Morissette

Research output: Contribution to journalArticle

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Abstract

Determining the manner in which food webs will respond to environmental changes is difficult because the relative importance of top-down vs. bottom-up forces in controlling ecosystems is still debated. This is especially true in the Arctic tundra where, despite relatively simple food webs, it is still unclear which forces dominate in this ecosystem. Our primary goal was to assess the extent to which a tundra food web was dominated by plant-herbivore or predator-prey interactions. Based on a 17-year (1993-2009) study of terrestrial wildlife on Bylot Island, Nunavut, Canada, we developed trophic mass balance models to address this question. Snow Geese were the dominant herbivores in this ecosystem, followed by two sympatric lemming species (brown and collared lemmings). Arctic foxes, weasels, and several species of birds of prey were the dominant predators. Results of our trophic models encompassing 19 functional groups showed that ,10% of the annual primary production was consumed by herbivores in most years despite the presence of a large Snow Goose colony, but that 20â¿¿100% of the annual herbivore production was consumed by predators. The impact of herbivores on vegetation has also weakened over time, probably due to an increase in primary production. The impact of predators was highest on lemmings, intermediate on passerines, and lowest on geese and shorebirds, but it varied with lemming abundance. Predation of collared lemmings exceeded production in most years and may explain why this species remained at low density. In contrast, the predation rate on brown lemmings varied with prey density and may have contributed to the high-amplitude, periodic fluctuations in the abundance of this species. Our analysis provided little evidence that herbivores are limited by primary production on Bylot Island. In contrast, we measured strong predator-prey interactions, which supports the hypothesis that this food web is primarily controlled by top-down forces. The presence of allochthonous resources subsidizing top predators and the absence of large herbivores may partly explain the predominant role of predation in this low-productivity ecosystem.
Original languageEnglish
Pages (from-to)1707-1716
Number of pages10
JournalEcology
Volume93
Issue number7
DOIs
Publication statusPublished - 2012
Externally publishedYes

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tundra
trophic relationships
food webs
food web
herbivore
herbivores
ecosystems
ecosystem
modeling
predator
Anser caerulescens
predators
primary production
primary productivity
predator-prey interaction
predation
predator-prey relationships
snow
Nunavut
Vulpes lagopus

Cite this

Legagneux, P., Gauthier, G., Berteaux, D., Bety, J., Cadieux, M-C., Bilodeau, F., ... Morissette, L. (2012). Disentangling trophic relationships in a High Arctic tundra ecosystem through food web modeling. Ecology, 93(7), 1707-1716. https://doi.org/10.1890/11-1973.1
Legagneux, P ; Gauthier, Gilles ; Berteaux, D ; Bety, J ; Cadieux, M-C ; Bilodeau, Frederic ; Bolduc, E ; McKinnon, L ; Tarroux, A ; Therrien, J-F ; Morissette, L. / Disentangling trophic relationships in a High Arctic tundra ecosystem through food web modeling. In: Ecology. 2012 ; Vol. 93, No. 7. pp. 1707-1716.
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Legagneux, P, Gauthier, G, Berteaux, D, Bety, J, Cadieux, M-C, Bilodeau, F, Bolduc, E, McKinnon, L, Tarroux, A, Therrien, J-F & Morissette, L 2012, 'Disentangling trophic relationships in a High Arctic tundra ecosystem through food web modeling', Ecology, vol. 93, no. 7, pp. 1707-1716. https://doi.org/10.1890/11-1973.1

Disentangling trophic relationships in a High Arctic tundra ecosystem through food web modeling. / Legagneux, P; Gauthier, Gilles; Berteaux, D; Bety, J; Cadieux, M-C; Bilodeau, Frederic; Bolduc, E; McKinnon, L; Tarroux, A; Therrien, J-F; Morissette, L.

In: Ecology, Vol. 93, No. 7, 2012, p. 1707-1716.

Research output: Contribution to journalArticle

TY - JOUR

T1 - Disentangling trophic relationships in a High Arctic tundra ecosystem through food web modeling

AU - Legagneux, P

AU - Gauthier, Gilles

AU - Berteaux, D

AU - Bety, J

AU - Cadieux, M-C

AU - Bilodeau, Frederic

AU - Bolduc, E

AU - McKinnon, L

AU - Tarroux, A

AU - Therrien, J-F

AU - Morissette, L

PY - 2012

Y1 - 2012

N2 - Determining the manner in which food webs will respond to environmental changes is difficult because the relative importance of top-down vs. bottom-up forces in controlling ecosystems is still debated. This is especially true in the Arctic tundra where, despite relatively simple food webs, it is still unclear which forces dominate in this ecosystem. Our primary goal was to assess the extent to which a tundra food web was dominated by plant-herbivore or predator-prey interactions. Based on a 17-year (1993-2009) study of terrestrial wildlife on Bylot Island, Nunavut, Canada, we developed trophic mass balance models to address this question. Snow Geese were the dominant herbivores in this ecosystem, followed by two sympatric lemming species (brown and collared lemmings). Arctic foxes, weasels, and several species of birds of prey were the dominant predators. Results of our trophic models encompassing 19 functional groups showed that ,10% of the annual primary production was consumed by herbivores in most years despite the presence of a large Snow Goose colony, but that 20â¿¿100% of the annual herbivore production was consumed by predators. The impact of herbivores on vegetation has also weakened over time, probably due to an increase in primary production. The impact of predators was highest on lemmings, intermediate on passerines, and lowest on geese and shorebirds, but it varied with lemming abundance. Predation of collared lemmings exceeded production in most years and may explain why this species remained at low density. In contrast, the predation rate on brown lemmings varied with prey density and may have contributed to the high-amplitude, periodic fluctuations in the abundance of this species. Our analysis provided little evidence that herbivores are limited by primary production on Bylot Island. In contrast, we measured strong predator-prey interactions, which supports the hypothesis that this food web is primarily controlled by top-down forces. The presence of allochthonous resources subsidizing top predators and the absence of large herbivores may partly explain the predominant role of predation in this low-productivity ecosystem.

AB - Determining the manner in which food webs will respond to environmental changes is difficult because the relative importance of top-down vs. bottom-up forces in controlling ecosystems is still debated. This is especially true in the Arctic tundra where, despite relatively simple food webs, it is still unclear which forces dominate in this ecosystem. Our primary goal was to assess the extent to which a tundra food web was dominated by plant-herbivore or predator-prey interactions. Based on a 17-year (1993-2009) study of terrestrial wildlife on Bylot Island, Nunavut, Canada, we developed trophic mass balance models to address this question. Snow Geese were the dominant herbivores in this ecosystem, followed by two sympatric lemming species (brown and collared lemmings). Arctic foxes, weasels, and several species of birds of prey were the dominant predators. Results of our trophic models encompassing 19 functional groups showed that ,10% of the annual primary production was consumed by herbivores in most years despite the presence of a large Snow Goose colony, but that 20â¿¿100% of the annual herbivore production was consumed by predators. The impact of herbivores on vegetation has also weakened over time, probably due to an increase in primary production. The impact of predators was highest on lemmings, intermediate on passerines, and lowest on geese and shorebirds, but it varied with lemming abundance. Predation of collared lemmings exceeded production in most years and may explain why this species remained at low density. In contrast, the predation rate on brown lemmings varied with prey density and may have contributed to the high-amplitude, periodic fluctuations in the abundance of this species. Our analysis provided little evidence that herbivores are limited by primary production on Bylot Island. In contrast, we measured strong predator-prey interactions, which supports the hypothesis that this food web is primarily controlled by top-down forces. The presence of allochthonous resources subsidizing top predators and the absence of large herbivores may partly explain the predominant role of predation in this low-productivity ecosystem.

KW - Bylot Island

KW - Canada

KW - Chen caerulescens atlantica

KW - climate change

KW - Ecopath

KW - lemmings

KW - mass balance trophic models

KW - predation

KW - Snow Geese

KW - top-down control.

U2 - 10.1890/11-1973.1

DO - 10.1890/11-1973.1

M3 - Article

VL - 93

SP - 1707

EP - 1716

JO - Ecology

JF - Ecology

SN - 0012-9658

IS - 7

ER -

Legagneux P, Gauthier G, Berteaux D, Bety J, Cadieux M-C, Bilodeau F et al. Disentangling trophic relationships in a High Arctic tundra ecosystem through food web modeling. Ecology. 2012;93(7):1707-1716. https://doi.org/10.1890/11-1973.1