Across Europe, butterfly populations are undergoing huge declines, with grassland butterfly abundance dropping by 39 percent between 1990 and 2017. Spain’s Catalonia region offers an extreme example of this continent-wide wave of biodiversity loss. Over the past 25 years, populations of the most common grassland species have declined here by 71 percent, reports Bridget Huber in FERN’s latest story, produced with National Geographic.
“Butterflies, like other pollinators, are being squeezed from two sides. In some places, as small-scale livestock farms give way to industrial agriculture, butterfly-friendly meadows are being aggregated into much larger fields of a single crop like corn or sunflowers. In others, pastures and fields are being abandoned and are slowly turning to forest. Both trends threaten butterflies,” Huber writes.
More than three-quarters of the grasslands in the European Union have an “unfavorable” conservation status — a broad designation that can mean anything from needing improvement to being lost entirely. In the U.K. and the Netherlands, for example, less than 5 percent of so-called semi-natural grasslands remain.
Intensive farming is clearly bad for biodiversity. Few wild plants and animals can survive practices like planting vast fields with a single crop, widespread use of pesticides, and frequent mowing and plowing.
But counterintuitively, too little human intervention also harms these grassland ecosystems, and thus butterfly populations. “Forest encroachment is one of the reasons behind this collapse,” says biologist Constantí Stefanescu, who runs the Catalan Butterfly Monitoring Scheme, “but intensification is the other side.”