The examples of flora and fauna disappearing because of human excesses over the past 50 years are manifold, but research has found that the decline of a characterful bat began in the UK when its trees were felled for shipbuilding 500 years ago.
Experts from the University of Exeter and the Bat Conservation Trust (BCT) have concluded that a 99% drop in Britain’s western barbastelle bat populations began when trees were chopped down in the early days of Britain’s empire building.
The conclusion was made possible by analysis of bat DNA that can pinpoint a “signature” of the past, including periods when populations declined, leading to more inbreeding and less genetic diversity.
Dr Orly Razgour, a molecular ecologist and conservation biologist at the university, said: “These bats usually roost in mature oak and beech trees, and move around every few nights – so they benefit from areas with substantial woodland cover.
“Our findings reveal that the northern and southern British populations have declined over several centuries, beginning about 500 years ago. This coincides with a period of widespread tree-felling to supply wood for colonial shipbuilding. It is likely that the decline we found was triggered by this loss of woodland – which has continued since that period.”
The western barbastelle bat’s distinctive features include large ears that meet in the middle, a flattened face with a pug-like nose and dark silky fur with white tips. It measures 4cm to 5cm in length and has a wingspan of about 26cm. Females give birth in early summer and raise a single pup each year.
For the study, the researchers humanely caught and tested western barbastelle bats in 15 British, Spanish and Portuguese forests.
Dr Katherine Boughey, the head of science and monitoring at BCT, said: “This technique is a gamechanger for bat conservation. Until now, we have only been able to look at recent changes in populations, though anecdotal evidence suggests UK bat populations are at historic lows. Now we have evidence for the historic decline of barbastelle but we urgently need similar evidence for other bat species.”
The BCT says that in the UK, the “very rare” species is found in just a few spots in southern and central England and Wales.
The paper spelling out the findings is published in the Journal of Applied Ecology.
