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Effects of changes in isotopic baselines on the evaluation of food web structure using isotopic functional indices

Belle, Simon and Cabana, Gilbert (2020). Effects of changes in isotopic baselines on the evaluation of food web structure using isotopic functional indices. PeerJ. 8 , e9999
[Research article]

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Background. This study aimed to assess whether ecological inferences from isotopic functional indices (IFIs) are impacted by changes in isotopic baselines in aquatic food webs. We used sudden CO2-outgassing and associated shifts in DIC- delta C-13 brought by waterfalls as an excellent natural experimental set-up to quantify impacts of changes in algal isotopic baselines on ecological inferences from IFIs.Methods. Carbon (delta C-13) and nitrogen (delta N-15) stable isotopic ratios of invertebrate communities sharing similar structure were measured at above- and below-waterfall sampling sites from five rivers and streams in Southern Quebec (Canada). For each sampled invertebrate community, the six Laymans IFIs were then calculated in the delta-space (delta C-13 vs. delta N-15).Results. As expected, isotopic functional richness indices, measuring the overall extent of community trophic space, were strongly sensitive to changes in isotopic baselines unlike other IFIs. Indeed, other IFIs were calculated based on the distribution of species within delta-space and were not strongly impacted by changes in the vertical or horizontal distribution of specimens in the delta-space. Our results highlighted that IFIs exhibited different sensitivities to changes in isotopic baselines, leading to potential misinterpretations of IFIs in river studies where isotopic baselines generally show high temporal and spatial variabilities. The identification of isotopic baselines and their associated variability, and the use of independent trophic tracers to identify the actual energy pathways through food webs must be a prerequisite to IFIs-based studies to strengthen the reliability of ecological inferences of food web structural properties.

Authors/Creators:Belle, Simon and Cabana, Gilbert
Title:Effects of changes in isotopic baselines on the evaluation of food web structure using isotopic functional indices
Series Name/Journal:PeerJ
Year of publishing :2020
Article number:e9999
Number of Pages:16
Publisher:PEERJ INC
Publication Type:Research article
Article category:Scientific peer reviewed
Version:Published version
Copyright:Creative Commons: Attribution 4.0
Full Text Status:Public
Subjects:(A) Swedish standard research categories 2011 > 1 Natural sciences > 106 Biological Sciences (Medical to be 3 and Agricultural to be 4) > Ecology
Keywords:Aquatic food webs, Trophic structure, Stable isotopes, Waterfalls
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Additional ID:
Type of IDID
Web of Science (WoS)000582413000007
ID Code:18716
Faculty:NJ - Fakulteten för naturresurser och jordbruksvetenskap
Department:(NL, NJ) > Dept. of Aquatic Sciences and Assessment
Deposited By: SLUpub Connector
Deposited On:19 Nov 2020 16:43
Metadata Last Modified:15 Jan 2021 19:18

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