West European hedgehog (Erinaceus europaeus) decline in Great Britain: evidence from multiple national scale surveys

Abstract

There are increasing concerns about the population trends and conservation status of West European hedgehogs across their range. However, survey data for this species come from multiple independent projects with different aims and constraints; as such, data remain difficult to integrate and interpret. We collate and analyse hedgehog data from five separate recording schemes across Britain, representing the most complete information on population trends of the species to date. Analyses of three surveys, the longest going back to 1981, all show declines at rural sites, with changes in hedgehog abundance of -70.7 and -54.4% between 1981 and 2023, and 2002 and 2013, respectively, and -80.4% in occurrence between 2002 and 2023. Worryingly, the estimated annual rate of decline accelerated from -2.88% between 1981 and 2023 to -6.81% between 2013 and 2023. Abundance changes in predominantly urban areas showed moderate increases in two surveys (6.7% between 2009 and 2023, and 20.0% between 2004 and 2024 respectively), while the same two surveys showed different trends in occurrence, declining until 2012/13 and thereafter either remaining below the baseline, or recovering to around the baseline value. Possible reasons for this discrepancy are discussed. Overall, the results suggest significant changes in the hedgehog population of Great Britain between 1981 and 2024, indicating substantial, widespread declines in rural areas, with implications for future conservation efforts targeted at this species.