How is the unpredictable weather affecting our wildlife?

The UK’s weather has always been predictably unpredictable, with extremes thankfully very rare. But how do our butterflies and birds cope with this and what could a warming climate mean for them?

By Jeremy Coles

15 July 2016

It’s not exactly been a scorching start to the season – less of a "barbeque summer" and more of a "dodge the downpours" kind of summer – so extreme heat and drought is one thing our butterflies and birds haven’t had to cope with.

For the vast majority of UK butterfly species, cold and wet summers result in reduced populations

The weather so far this year has been at the other end of the scale. Spring took a long time to get going with temperatures generally below average and snow falling in April. The start to summer has also been less than typical, with June being a washout for many parts of the UK.

Together with last year’s cold, wet summer it could indicate problems for some of our insect populations.

“The weather has a massive influence on UK butterfly populations from generation to generation, year to year,” says Richard Fox, head of recording for Butterfly Conservation.

During prolonged spells of wet and cold during their flight period, individual butterflies are not able to disperse or feed, set up territories or engage in courtship.

And, most importantly, they aren't able to lay eggs.

So by limiting all these behaviours, explains Fox, extended periods of cold and wet weather can directly reduce the breeding success of our butterflies. However, it can spell double trouble as their caterpillars grow more slowly in colder conditions and are more prone to predation and disease.

“For the vast majority of UK butterfly species, cold and wet summers result in reduced populations,” he says.

There are some species that have evolved to cope with the cooler, wetter climates of northern and upland Britain, such as the mountain ringlet and Scotch argus, where they live amongst the longer vegetation and grassy tussocks. Nevertheless, stresses Fox, they still like some warm and sunny days in order to get out and reproduce.

Continued ...