Abstract

It is increasingly important to be aware of trends in species abundances in order to be able to act ahead of possible irrecoverable declines and extinctions. Long-term monitoring of species is generally used to determine how a species is faring, which is essential knowledge for conservation planning and design. However, monitoring programmes that encompass large areas and long timespans are rare or non-existent for the vast majority of species. Citizen-science-based datasets provide a wealth of data on past and present species' occurrences but are often biased to a large extent. We evaluate the potential use of such datasets by subsampling datasets collected over different time periods to detect trends in the long-term temporal abundance of West European hedgehogs (Erinaceus europaeus), a species which is thought to be in decline in parts of its geographic range. We used subsampling as a means to account for quantitative differences between two non-systematic datasets of West European hedgehog occurrences in England; one dataset was collected by the public between 1960 and 1975 and one was collected between 2000 and 2015. Here, we confirm and quantify previous anecdotal evidence of a long-term decline of the species throughout England. We find that although the West European hedgehog is still widespread in England, a 5.0 to 7.4 % decline in occupied grid cells was observed when comparing the 2000-2015 dataset to the previous survey in 1960-1975 after adjusting for differences in effort. This suggests that the decline of the relative abundance of West European hedgehogs is moderate in England, 25 % being an amber alert for birds of conservation concern in the UK. Importantly, we show that subsampling disparate citizen-science datasets is a useful tool for monitoring species population trends.

Keywords

Citizen science; Datasets; Population trends; Subsampling; West European hedgehog

Published in

European Journal of Wildlife Research
2016, Volume: 62, number: 4, pages: 407-413

UKÄ Subject classification

Ecology


Publication identifier

DOI: https://doi.org/10.1007/s10344-016-1013-1

Permanent link to this page (URI)

https://res.slu.se/id/publ/86744