First ever national analysis of stag beetles announced giving crucial insight into species population and distribution in the UK - People’s Trust for Endangered Species

Over 25 years of citizen science data provide exceptional resource for flagship species

Data from a long-running citizen science survey is being used in the first ever national analysis of stag beetle population distribution in the UK. An astonishing 82,883 records submitted to the Great Stag Hunt, run by People’s Trust for Endangered Species (PTES) have been collected since 1998. Conservation scientists from PTES have analysed these alongside historical museum collection data to identify potential population distribution changes for this impressive and much-loved species, the largest beetle species in Europe. The results will be important in directing future conservation efforts for stag beetles in the UK and have just been published – with open access – in the journal Insect Conservation and Diversity.

The results show a broadly stable distribution of stag beetles in the UK, although the data indicate a recent decline in the southwestern part of the species’ range and it is not clear why this is the case. There are also indications that in recent years, the abundance of adult stag beetles has decreased, as average counts of multiple beetles seen at one time have declined over the years. This leaves no room for complacency in implementing conservation management actions for this flagship species. Our understanding is further complicated by the fact that, while we have a solid understanding on their distribution, there isn’t a robust dataset on actual numbers of adult beetles and larvae, a difficult task for invertebrates.

The Great Stag Hunt dataset is already an impressively long length but with the support of a research intern at PTES and the Natural History Museum, it has been possible to undertake a comparison with historical data from seven museum collections as well, some of which date back over 100 years. The result is the creation of a comprehensive and long-running data series, particularly useful for invertebrate species where such data are often scarcer. Tracking invertebrate populations is challenging, but with the public’s help, conservationists can now target their efforts more effectively. The study also underlines how valuable historical museum records remain for modern scientific research.