Lisa Abend at the NY Times:
The zoologist Johan Eklöf began to consider the disappearance of darkness in our brightly lit world in 2015, when he was out counting bats in southern Sweden. The surrounding grounds were dark, as they had been decades earlier when his academic adviser had tallied the bat populations in the region’s churches. In the intervening years, however, those churches — whose belfries are famously appreciated by the winged mammals — had been illuminated with floodlights. “I started to think, how do the bats actually react to this?” Eklöf says.
The short answer: Not well. Together with his adviser, Jens Rydell, Eklöf launched a new bat census and discovered that in 30 years — the average bat’s life span — fully half the area’s colonies had disappeared.
more here.