Directional trends in species composition over time can lead to a widespread overemphasis of year‐to‐year asynchrony
Résumé
Methods: An approach based on three-term local quadrat variance (T3) which assesses population variability in a three-year moving window, was used to overcome species directional trend effects. This “detrending” approach was applied to common indices of synchrony across a worldwide collection of 77 temporal plant community datasets comprising almost 7,800 individual plots sampled for at least six years. Plots included were either maintained under constant “control” conditions over time or were subjected to different management or disturbance treatments.
Results: Accounting for directional trends increased the detection of year-to-year synchronous patterns in all synchrony indices considered. Specifically, synchrony values increased significantly in ~40% of the datasets with the T3 detrending approach while in ~10% synchrony decreased. For the 38 studies with both control and manipulated conditions, the increase in synchrony values was stronger for longer time series, particularly following experimental manipulation.
Conclusions: Species’ long-term directional trends can affect synchrony and stability measures potentially masking the ecological mechanism causing year-to-year
Auteurs, date et publication :
Auteurs Enrique Valencia , Francesco de Bello , Jan Lepš , Thomas Galland , Anna E‐Vojtkó , Luisa Conti , Jiří Danihelka , Jürgen Dengler , David J. Eldridge , Marc Estiarte , Ricardo García‐González , Eric Garnier , Daniel Gómez , Susan Harrison , Tomas Herben , Ricardo Ibáñez , Anke Jentsch , Norbert Juergens , Miklós Kertész , Katja Klumpp
Publication : Journal of Vegetation Science
Date : 2025
Volume : 31
Issue : 5
Pages : 792-802