UK Butterfly Numbers at Record Low in ‘Warning Sign to Us All,’ Conservationists Report

Following record-low reports of butterflies in the UK, British charity Butterfly Conservation is sounding the alarm.

The charity, which crowdsources data from UK participants through their Big Butterfly Count, put out a blog post explaining that participants are reporting “just over half” the amount of butterflies compared to this time last year. This year’s Big Butterfly Count concludes on August 4.

“The lack of butterflies this year is a warning sign to us all. Nature is sounding the alarm and we must listen,” said Dan Hoare, Butterfly Conservation’s director of conservation said in the post. Butterflies are a key indicator species. When they are in trouble we know the wider environment is in trouble too.”

Butterfly Conservation points to a “wet and windy spring,” along with colder-than-usual summer temperatures to explain the decline, because butterflies mate less often in wet environments, although the current season’s weather is not the only factor. “80% of butterflies in the UK have declined since the 1970s,” the blog post said, “with habitat loss, climate change and pesticide use the main drivers of this decline,” referencing one of their previous reports from 2023.

While the butterflies are mating less often this season due to the wet spring, last year’s drought is also harming them because the plants their caterpillars eat need to be properly watered, reported The Guardian.

A 2020 study published in the British Ecological Society’s Journal of Animal Ecology points out that because some butterfly species tend to struggle with controlling their body temperatures, they seek out “microhabitats” at the right temperature.

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These butterflies, which are classified as specialist species due to their specific habitat requirements, tend to be among the first to be impacted by climate change, making them important indicator species to monitor as an early warning sign for the impacts of climate change.

This makes the current decline in UK butterflies all the more dire, as climate change causes fluctuations in both weather patterns and temperature. Butterflies are also important for pollination and pest control, meaning their absence will likely have consequences for habitats too.

Hoare urged people in the UK to help by monitoring butterfly counts. “People are telling us that they aren’t seeing butterflies, but simply telling us is not enough,” he said. “We need everyone to record what they are or aren’t seeing by doing a Big Butterfly Count as this will give us the evidence we need to take vital action to conserve our butterfly species.”