The (Declining) Butterfly Effect

As springtime begins, you may take for granted the miniature works of art that bob along with the wind and flutter before your eyes. You may even try to avoid these intricate beauties — grouping them with the likes of wasps, bluebottles, and other unnerving sky pests. However, the common butterfly, although small and delicate, plays a vital role in our planet’s survival.

A recent study published in the journal Science has presented an analysis of butterfly population data amassed from over 76,000 surveys conducted across the US over the past two decades. The results show that from the year 2000 to 2020, butterfly numbers have decreased by 22 per cent, at a rate of 1.3 per cent per year. At this rate, one can expect US butterflies to suffer widespread extinction before the turn of the century. In the UK, their wipeout may be seen as soon as 2050 if the worst scenarios regarding air pollution and greenhouse gas emissions come to fruition.

There are 59 species of butterfly in the UK — 80 per cent of which are in decline — that play an important role in pollination efforts, increasing biodiversity, and providing a source of nutrition for the organisms above them in the food chain. Because of this, these beautiful insects are often enriched in the healthiest environments and ecosystems, serving as important indicator species. Considering the stability they provide to our ecosystems, reduced butterfly numbers are likely to have a detrimental impact.

Imagine a world devoid of plant life — one in which you can’t pick a crop without it disintegrating. This is a world we are gradually creeping towards, with the loss of butterfly populations in areas rich with plant life only accelerating our approach. In the tropical grassland regions of countries like Venezuela, for example, butterflies account for 13.9 per cent of pollination efforts, closely following bees as the second most common pollinator. However, since some bees have specific preferences for pollinating only the inner parts of flowers, the tendency of butterflies (and flies) to forage the remaining parts ensures a 50 per cent greater coverage of the crop, as has been demonstrated in cotton plants by researchers at the University of Vermont in 2021. This is particularly relevant for cotton production in Texas, where butterflies are thought to contribute around $120 million worth of the plant.

In the face of this threat, it is not unreasonable to hope that humanity has learned from the extinction of previous insect species — between 250,000 and 500,000 are thought to have gone extinct across the world in the last 150 years. However, the current demise of butterflies can be directly attributed to the habitat loss, pollution, pesticide use, and climate change caused by human beings. It is clear that we have a lot of blood — or rather, broken wings — on our hands.

Nevertheless, there may still be time to attenuate, and even heal, the damage that has already been done. Efforts to protect what few butterflies we have left have included a ban on neonicotinoid pesticides (which are lethal to insects), forwarded by the declaration of the UK Butterfly Emergency in 2024. Future endeavours in habitat restoration, protection, and management, as well as dampening climate change and global warming, will be vital for recovering butterfly numbers.

If you are familiar with the butterfly effect, you will be aware of the drastic impact that losing a single one of these precious creatures can cause. If humanity is to continue on its current path, eliminating millions of delicate, fluttering wings, a shockwave of ecological chaos will inevitably follow. 

Illustration by Isabella Abbott