Butterflies suffer sharp decline

  • In the past 20 years, Europe’s grassland butterfly population has dropped by 50 %
  • Belgium is no exception to this trend

 

All is not rosy in the world of butterflies, especially not for those that inhabit grasslands. According to the European Environment Agency (EEA), there was a 50 % decline in the number of lepidopterans between 1990 and 2011. “It’s very worrying,” states the Agency. “These butterflies are representative indicators of trends that have been observed in the majority of other terrestrial insects.”

 

Just like wild bees, honeybees and bumblebees, butterflies are also pollinators.

 

Jean-Sébastien Rousseau-Piot of Natagora, a Belgian pro-nature organization, is not surprised. “We’ve known for a while that butterfly populations are decreasing, and that grassland butterflies are particularly threatened,” he says. Out of 17 species of butterflies studied, eight are in decline, two have remained stable, and one is on the rise. For the other species, the trends are “uncertain”.

 

The reason for this calamity? “An intensifying of agricultural practices and poor management of the grasslands ecosystem,” claims the EEA. “In Belgium,” says Rousseau-Piot, “the situation is without doubt the most serious.” According to official censuses in Wallonia, “Half of all day-flying butterfly species (52 of 101 species) appear to be under threat or are already extinct.”

 

“Belgium is a very agricultural country. And its agriculture is extremely intensive,” continues the expert. “Natural grasslands practically don’t exist anymore. Agricultural grasslands are in fact hay fields, enriched with fertilizers, often chemical, sown with grasses earmarked for animal feed. Floral diversity has decreased both in Belgium and across western Europe.” But butterflies are very much linked to flowers and plants, from which they gather pollen, on which they also lay eggs (five species lay their eggs on flowers but do not pollinate them) and under which they take shelter.

 

What about floral grasslands and flower beds running along the edge of fields? The plants that are sown there have a weak spread potential and are not particularly favorable to butterflies,. On the other hand, enriching grasslands encourages the emergence of one or two dominant plant species that override diversity. There is little chance that the situation is going to improve dramatically any time soon. But individuals, even those who live in cities, can do their bit by turning away from traditional horticultural varieties in favor of wild indigenous plants.

 

MICHEL DE MUELENAERE

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