Dataset: Weather Surveillance Radar measured aerial insect abundance in the UK, 2015-2022

Data describing the aerial abundance of insect over the United Kingdom from 2015-2022. Includes code produced for the manuscript: O'Connell-Booth, R., et al. (2025) No effect of agri-environment schemes on radar-measured aerial insect abundance at landscape scale in England.Abstract: Agri-environment schemes (AES) commonly represent the largest financial investment in biodiversity conservation at a national or international level, but evidence these interventions are effective remains equivocal. Here, we develop a novel and general method for assessing the impact of conservation interventions using Weather Surveillance Radar (WSR) to produce spatially explicit time series of aerial insect abundance over 21,000 km2 of England from 2015-2022. Using this dataset, we evaluated the landscape-scale causal effect of AES across 15 natural experiments involving paired AES and control sites. We adapt methods from the difference in differences literature to analyse these natural experiments using a matched dynamic BACI design, new to conservation science and ecology. We find no natural experiment which indicates a positive causal effect of AES, even at high levels of expenditure (ranging from £34 km-2 to £5122 km-2). When considering all 1884 km2 of agricultural land in England covered by the radar, we find a weak but significant negative correlation between AES and aerial insect abundance, corresponding to 0.289% fewer insects per £1,000 of AES expenditure. We find stronger, positive relationships between insect numbers of the percentage cover of woodland and semi-natural grassland. Our results provide the most robust evaluation of the benefits of AES and indicate that AES are not working to conserve aerial insects, as measured by WSR. We demonstrate the utility of landscape-scale conservation impact assessment using WSR-measured insect abundance paired with econometric impact assessment designs, a technique broadly applicable to problems in insect conservation science.