Let there be night, for wildlife's sake

IT IS time to take back the night for wildlife. That was the rallying call from a landmark session on light pollution at the Society for Conservation Biology .

The disruptive effects on animals of our penchant for bright lights has rarely impinged on public consciousness. Notable exceptions are when turtle hatchlings head inland to the bright lights of a beach resort instead of the safety of the moonlit sea, or birds collide en masse with brightly lit buildings.

It is rapidly becoming clear, though, that light pollution subtly interferes with the growth, behaviour and survival of many nocturnal species - not just those that hit the headlines.

The threats posed by the humble street lamp do not rival the wholesale destruction of tropical forests and other habitats, or indeed the threat of climate change. But participants in the session at the Edmonton meeting agreed that planners should spare a thought for wildlife when installing lighting. "We've taken away the night," warns Travis Longcore of the University of Southern California in Los Angeles, who chaired the session.

For instance, Emma Stone of the University of Bristol, UK, has shown that high-pressure sodium street lights can divert lesser horseshoe bats from their usual routes between roosts and foraging grounds. Such diversion may be energetically costly - all the more of a worry as the bats in the study were pregnant.