Kreyling, JuergenExperimental Plant Ecology, Institute for Botany and Landscape Ecology, Greifswald University, , D‐17487 Greifswald, Germany
Author
Schweiger, Andreas H.Plant Ecology, Bayreuth, Center of Ecology and Environmental Research (BayCEER), University of Bayreuth, , 95447 Bayreuth, Germany
Author
Bahn, MichaelInstitute of Ecology, University of Innsbruck, , 6020 Innsbruck, Austria
Author
Ineson, PhilDepartment of Biology, University of York, , Heslington, York, YO10 5DD UK
A fundamental challenge in experimental ecology is to capture nonlinearities of ecological responses to interacting environmental drivers. Here, we demonstrate that gradient designs outperform replicated designs for detecting and quantifying nonlinear responses. We report the results of (1) multiple computer simulations and (2) two purpose‐designed empirical experiments. The findings consistently revealed that unreplicated sampling at a maximum number of sampling locations maximised prediction success (i.e. the R² to the known truth) irrespective of the amount of stochasticity and the underlying response surfaces, including combinations of two linear, unimodal or saturating drivers. For the two empirical experiments, the same pattern was found, with gradient designs outperforming replicated designs in revealing the response surfaces of underlying drivers. Our findings suggest that a move to gradient designs in ecological experiments could be a major step towards unravelling underlying response patterns to continuous and interacting environmental drivers in a feasible and statistically powerful way.
Kreyling, J., Schweiger, A. H., Bahn, M., Ineson, P., Migliavacca, M., Morel-Journel, T., Christiansen, J. R., Schtickzelle, N., & Larsen, K. S. (2018). To replicate, or not to replicate - that is the question: how to tackle nonlinear responses in ecological experiments. Ecology Letters (Online), 21(11), 1629-1638. https://doi.org/10.1111/ele.13134 (Original work published 2018)