InsectChange: a global database of temporal changes in insect and arachnid assemblages.

Area of Science:

• Ecology and Environmental Science
• Biodiversity Research
• Conservation Biology

Background:

• Insects are ecologically vital and diverse, yet face documented declines.
• Existing insect monitoring programs are numerous but lack a unified global database for long-term trend analysis.
• A comprehensive database is needed to synthesize data on insect abundance changes.

Purpose of the Study:

• To compile a global database of long-term (≥10 years) insect and arachnid assemblage monitoring studies.
• To facilitate synthetic analyses of insect abundance and biomass changes over time.
• To provide a standardized resource for researchers studying insect population dynamics.

Main Methods:

• Systematic search of scientific literature and public repositories for long-term monitoring studies (≥10 years, ≥2 sampling events).
• Inclusion of studies reporting total community abundance or biomass for terrestrial and freshwater insect/arachnid assemblages.
• Data extraction from tables, figures, and appendices, with standardization of trapping effort where raw data were available; collection of site provenance and environmental data.

Main Results:

• The database contains 1,668 plot-level time series from 165 studies, with samples collected between 1925 and 2018.
• Data cover both terrestrial (1,053 plots) and freshwater (615 plots) realms, with most studies from Europe and North America.
• The median monitoring duration was 19 years, with 12 sampling years; abundance data were available for 129 studies.

Conclusions:

• The compiled database represents a significant advancement for synthesizing long-term insect monitoring data globally.
• This resource will enable robust analyses of insect population trends and inform conservation strategies.
• The data set is publicly available under a CC-BY license, promoting open science and further research.