Copenhagen -- Following decades of worrying decline, Europe's bat population increased by 43 per cent between 1993 and 2011, according to a new study released by the European Environment Agency (EEA).
The upsurge in population has been aided by legislation and treaties that promote conservation measures, including the UNEP-administered Agreement on the Conservation of Populations of European Bats (EUROBATS), the Berne Convention on the Conservation of European Wildlife and Natural Habitats (Council of Europe) and the European Union's Flora Fauna Habitat Directive.
'It is extremely encouraging to see bat populations increasing after massive historic declines,' EEA Executive Director Hans Bruyninckx said. 'It suggests that targeted conservation policies over the last years have been successful.'
'But many bat species are still endangered, so preserving their habitats is still an important priority,' he added. 'Monitoring bats also helps understand changes in wider ecosystems, including climate change, as they are highly sensitive to environmental change.'
The decline in populations prior to conservation efforts came largely as a result of intensifying agriculture, changes in land use, intentional killing and destruction of roosts.
The EEA study is the most comprehensive of its kind, surveying 16 of the 45 European bat species in nine countries: Latvia, Hungary, the Netherlands, Austria, Portugal, Slovenia, Slovakia, the United Kingdom and Germany.
While most of the bat species surveyed remained stable or increased modestly in population, the species known as the Whiskered Bat (Myotis mystacinus) and Brandt's Bat (Myotis brandtii) registered a strong increase. Only the Grey Long-Eared Bat (Plecotus austriacus) showed a decline.
However, as bats live long lives and reproduce slowly they remain sensitive to environmental and human pressures. Many of the species studied are therefore still considered rare and vulnerable, according to the EEA.
Bats contribute to economies by performing essential environmental functions. They control insect populations in agricultural regions, maintain forests and disperse pollen and seed over long distances.
On organic coffee plantations in Mexico, for example, bats consume more insects than birds do in the summer wet season. Over 200 insect species feed on and damage coffee plants. With pesticides banned on organic plantations, the role of bats is thus essential to the local economy.
In addition to bees, bats are a major contributor to natural pollination, an eco-service that significantly aids farming efforts, particularly in developing countries, and is estimated to be worth US$224 billion a year.
The recent study, to which a number of organizations and volunteers contributed data, is not the first time that the EUROBATS and partners have registered success in recent years.
In 2011, the UNEP-backed Year of the Bat , EUROBATS and the Bavarian Ministry for Environment and Health embarked on a project to conserve the last remaining habitats of the Greater Horseshoe Bat (Rhinolophus ferrumequinum), which was once common in south and central Germany but in the late 20th century became threatened with extinction.
The restored habitat, an abandoned farmhouse in Bavaria, was successfully turned into a breeding ground accommodating some 40 females and 30 pups at its outset.