Butterfly numbers are dropping – and scientists aren’t sure why

By Tanya Harrington

An annual survey known as the “Big Butterfly Count,” was conducted earlier this year, and recorded a worryingly low presence of butterflies and moths of around 12.2 per count – even lower than that found during the inordinately wet Summer of 2012. Stranger yet, these findings contrast the high numbers of butterflies and moths found in 2013, which were found to be around 23 per count. This particular survey began running in 2010, but there are records dating back to the 1970s which the group, Butterfly Conservation, also uses. Yet, despite these extensive information resources, scientists are still having trouble ascertaining the cause behind this recent drop.

Over 390,000 butterflies were counted by around 36,000 people, a statistic which certainly sounds proportionally healthy. However, the head of recording for the group, Richard Fox, described the findings as “shocking and disappointing,” stating that “the overall trend has been a decline,” and that there is concern that “a bad year will do lasting damage.”

Since the weather this Summer has been well suited to butterflies, this recent trend appears even more baffling. More so, it seems as though certain types of butterfly have been thriving in the good weather, whereas others have suffered from significant drops. Presence of the red admiral butterfly, for example, has increased by 70%, alongside a rise of 58% for the green-veined white butterfly as well. Contrasting this is the sharp drop in numbers of the common blue butterfly, which is down by 55%, as well as five other types which have dropped by at least 40%.

Richard Fox also noted the precarious nature of the situation, adding that “with some rarer species we are already at the point that colonies could be wiped out,” and that this recent plummet could leave them without enough butterflies for those colonies to make a comeback.

Considering the impact butterflies have on the ecosystem, it could even be likely that this fall in numbers could have further repercussions for the environment. However, with little to hint at what may have caused the fall in numbers, scientists and enthusiasts have been speculating.

Tim Sexton, from the Attenborough Nature Reserve in Nottinghamshire noted that “it seems like the species which migrate, like the red admiral, have done well,” hinting that perhaps Winter conditions could be to blame, as “those which wintered here have suffered.” This idea works alongside Richard Fox’s own, as he also mentioned “the most extreme thing was the exceptionally mild winter,” but added that, as far as definitive reasons go, “it is debated if that is a good or bad thing for butterflies,” perhaps since it is thought that butterflies fare well in warmer weather.

Both Mr Fox and Mr Sexton appear to be worried about the continued presence of Butterflies locally, with Mr Sexton mentioning that “we might even risk local extinctions,” and so it seems this could be another example of changing within ecosystems as a result of global temperature changes. However, without any definitive answer, it is important that this issue is looked into with the aim of recovery in mind.

Photo credit: tdlucas5000

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