Conservationists have been left baffled as to why Dorset’s butterfly population suffered a devastating drop in numbers this summer.


The number of butterflies spotted over the summer hit an all-time low, despite the UK experiencing ideal weather conditions for them to thrive, according to a Dorset-based charity, Butterfly Conservation.


The charity has published the results of its Big Butterfly Count which shows the majority of butterfly species' saw their populations fall. 


Some produced their worst numbers since the Big Butterfly Count scheme began.


There were 1205 counts across Dorset and the top five species found were meadow brown, large white, gatekeeper, small white and red admiral - but the number of gatekeeper found was down by 40%


Participants saw the lowest number of butterflies per count since the scheme began with an average of 12 butterflies spotted.


Figures were lower than those experienced during the cold and wet ‘disaster’ summer of 2012 – the worst year on record for UK butterflies.


Reason as to why butterflies have struggled despite optimum summer weather conditions are unclear.


Butterfly Conservation’s head of Recording, Richard Fox, said: “The drop in butterfly numbers this summer has been a shock and is a bit of a mystery. When we have cold, wet summers, as in 2012, we expect butterfly populations to plummet, but that wasn’t the case this year.


“The summer months were warmer than usual, yet most Big Butterfly Count participants saw fewer butterflies. Perhaps the very mild winter had a negative effect, or the cold spring, or perhaps the impacts of intensive farming and pesticides are really hitting these common species now.


“The importance of Big Butterfly Count is that it takes place every year over a long period. The longer it goes on the more we can learn about the causes that are driving the declines and in some cases, increases of our beautiful butterfly species.


“We are really grateful to the many thousands of people across the UK who do their bit to help butterflies by taking part in the Big Butterfly Count each summer.”


The Big Butterfly Count helps Butterfly Conservation find out how the UK’s common species are faring and how to best protect them in the future. 
Results can be found at www.bigbutterflycount.org

Butterfly decline

Gatekeeper - down by 40%

Comma - down by 46%

Small copper - down by 30%

Small tortoiseshell - down by 47%

Peacock - down by 42%