Biodiversité

Butterflies are better documented and monitored worldwide than any other nonpest taxon of insects ( 1 ). In the United Kingdom alone, volunteer recorders have sampled more than 750,000 km of repeat transects since 1976, equivalent to walking to the Moon and back counting butterflies ( 2 ). Such programs are revealing regional extinctions and population declines that began before 1900 ( 3 , 4 ). In a recent study, Habel et al. report a similar story based on inventories of butterflies and burnet moths since 1840 in a protected area in Bavaria, Germany ( 5 ). The results reveal severe species losses: Scarce, specialized butterflies have largely disappeared, leaving ecosystems dominated by common generalist ones. Similar trends are seen across Europe ( 6 ) and beyond, with protected areas failing to conserve many species for which they were once famed.