Evaluating Impact Using Time-Series Data.

Humanity's impact on the environment is increasing, as are strategies to conserve biodiversity, but a lack of understanding about how interventions affect ecological and conservation outcomes hampers decision-making. Time series are often used to assess impacts, but ecologists tend to compare average values from before to after an impact; overlooking the potential for the intervention to elicit a change in trend. Without methods that allow for a range of responses, erroneous conclusions can be drawn, especially for large, multi-time-series datasets, which are increasingly available. Drawing on literature in other disciplines and pioneering work in ecology, we present a standardised framework to robustly assesses how interventions, like natural disasters or conservation policies, affect ecological time series.HSW was supported by the Cambridge Trust Poynton Scholarship, Cambridge Department of Zoology J.S. Gardiner Studentship and Cambridge Philosophical Society; TA was supported by the Australian Research Council Future Fellowship (FT180100354) and the University of Queensland strategic funding; JG was supported by European Union’s Horizon 2020 Marie Skłodowska-Curie program (No. 706784) and VILLUM FONDEN (VKR023371); BIS was supported by a Royal Commission for the Exhibition of 1851 Research Fellowship; WJS is funded by Arcadia and JPGJ was supported by the Leverhulme Trust: RPG-2014-056