Town & Country
A great moth mystery
MOTHS are disappearing from British woods much faster than from farms or cities. According to a Rothamsted Research study, the greatest drop was recorded in broadleaf woodland, where populations not only more than halved, but the total weight of moths, their richness and their diversity also plummeted. This has baffled scientists, because deciduous woods are relatively more shielded from decline drivers, such as pesticides, light pollution and rising temperatures. Even higher deer density and reduced woodland management cannot fully explain the decrease in the insects’ numbers, because the researchers found that species feeding on forbs, shrubs and plants that require light, which would be most likely to suffer from overgrazing or shading, didn’t fare worse than those feeding on grasses, trees or lichens.
Although the specific causes of the drop remain unclear, the study’s lead author, Dan Blumgart, suggests that managing woodlands for wildlife should have a positive effect on moths. ‘These include removal of invasive understorey shrubs, such as rhododendron and laurel, and of non-native conifers. Old trees should be preserved, as well as dead and dying trees, as these provide many niches for specialist insects.’
