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Monteux S, Blume-Werry G, Gavazov K, Kirchhoff L, Krab EJ, Lett S, Pedersen EP, Väisänen M. Controlling biases in targeted plant removal experiments. THE NEW PHYTOLOGIST 2024; 242:1835-1845. [PMID: 38044568 DOI: 10.1111/nph.19386] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/30/2023] [Accepted: 10/19/2023] [Indexed: 12/05/2023]
Abstract
Targeted removal experiments are a powerful tool to assess the effects of plant species or (functional) groups on ecosystem functions. However, removing plant biomass in itself can bias the observed responses. This bias is commonly addressed by waiting until ecosystem recovery, but this is inherently based on unverified proxies or anecdotal evidence. Statistical control methods are efficient, but restricted in scope by underlying assumptions. We propose accounting for such biases within the experimental design, using a gradient of biomass removal controls. We demonstrate the relevance of this design by presenting (1) conceptual examples of suspected biases and (2) how to observe and control for these biases. Using data from a mycorrhizal association-based removal experiment, we show that ignoring biomass removal biases (including by assuming ecosystem recovery) can lead to incorrect, or even contrary conclusions (e.g. false positive and false negative). Our gradient design can prevent such incorrect interpretations, regardless of whether aboveground biomass has fully recovered. Our approach provides more objective and quantitative insights, independently assessed for each variable, than using a proxy to assume ecosystem recovery. Our approach circumvents the strict statistical assumptions of, for example, ANCOVA and thus offers greater flexibility in data analysis.
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Affiliation(s)
- Sylvain Monteux
- Department of Environmental Science, Stockholm University, SE-10691, Stockholm, Sweden
- Bolin Centre for Climate Research, Stockholm University, SE-10691, Stockholm, Sweden
- UiT The Arctic University Museum of Norway, NO-9006, Tromsø, Norway
| | - Gesche Blume-Werry
- Department of Ecology and Environmental Sciences, Climate Impacts Research Centre, Umeå University, SE-98107, Abisko, Sweden
| | - Konstantin Gavazov
- Swiss Federal Institute for Forest, Snow and Landscape Research WSL, CH-8903, Birmensdorf, Switzerland
| | - Leah Kirchhoff
- Department of Ecology and Environmental Sciences, Climate Impacts Research Centre, Umeå University, SE-98107, Abisko, Sweden
| | - Eveline J Krab
- Department of Soil and Environment, Swedish University for Agricultural Sciences SLU, SE-75651, Uppsala, Sweden
| | - Signe Lett
- Department of Biology, University of Copenhagen, DK-1165, Copenhagen, Denmark
| | - Emily P Pedersen
- Department of Ecology and Environmental Sciences, Climate Impacts Research Centre, Umeå University, SE-98107, Abisko, Sweden
- Swedish Polar Research Secretariat, Abisko Scientific Research Station, SE-98107, Abisko, Sweden
| | - Maria Väisänen
- Ecology and Genetics Research Unit, University of Oulu, FI-90014, Oulu, Finland
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Climatic history, constraints, and the plasticity of phytochemical traits under water stress. Ecosphere 2022. [DOI: 10.1002/ecs2.4167] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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