Fränzi Korner-nievergelt

Abstract Most studies on insect trends have focused on the past few decades, but major changes could have occurred earlier. If so, shifted baselines can result in misleading conclusions or poor conservation decisions. Here we analyse nine decades of insect trends in Switzerland and relate them to changes in land use and climate.

DATA AVAILABILITY STATEMENT The raw moth record data are hosted by info fauna and protected by a code of conduct but can be obtained from info fauna on request if in accordance with this code of conduct (https://www.infospecies.ch/de/daten). Moth record data with coarser spatial resolution and with a unique identifier for the sampling location and sampling details necessary to reproduce the models are available from the GBIF database https://doi.org/10.15468/dl.gcagva (GBIF.org, 2024).

1 Introduction Various environmental factors can influence the timing of reproduction. Rising spring temperatures are, for example, often associated with an earlier start of reproduction in birds (Dunn and Winkler 1999; Martin and Wiebe 2004; Pearce-Higgins, Yalden, and Whittingham 2005; Madsen et al. 2007; Halupka, Dyrcz, and Borowiec 2008; Smith et al. 2024). Droughts, extensive snow cover, or heavy precipitation can instead delay the start of reproduction (Martin and Wiebe 2004; Madsen et al.