Climate change shifting spring activity for birds and insects forward: study

The research finds aphids, moths and butterflies are now flying and birds are laying eggs much earlier than in the mid-20th century, but how much of a shift there has been depends on where in the UK and which habitat they are in.

The researchers warned variations in how different groups of animals were shifting their behaviour means wildlife could get “out of sync” with the life cycles of other species they rely on for food.

It also suggests wildlife will not be protected in habitats such as woodlands, which it had been thought might provide more stable conditions that could be a “buffer” to rising temperatures.

The shift towards an earlier spring is also happening in shady forests as well as more open areas, the study into the seasonal habits of more than 250 UK species found.

Lead author Dr James Bell, who heads up the Rothamsted Insect Survey, said: “There was already good evidence that spring is coming earlier each year, but what we didn’t expect to find was that it was advancing as much in forests as it is in open areas such as grassland.

“Equally, in areas where we’d expect to see much greater acceleration, such as urban parkland, the rates of advance appear to be the same.

“This all points to a complex picture emerging under climate change, which makes ecosystem responses hard to predict, and even harder for conservationists to prepare for.”

He added: “The work is important because is shows us that we cannot rely on habitat to slow down climate change impacts, even in woodlands and forests where the conditions are more stable, and which were expected to buffer against adverse changes.”

The detailed picture built up by the study, which used data that stretches back to 1960, reveals that the responses by species to climate change are not straightforward.

Moths which turn from caterpillars to adults on the wing earlier in the year seem to be more responsive to climate change that those which change later, with moths that start flying before June now doing so much earlier.

In the north of the UK, changes in the climate may have different impacts on species, as butterflies become active earlier in the warmer wetter west than the colder drier east, but the opposite is true for birds laying eggs.

And birds and butterflies that live on farmland – as well as birds that live in coastal areas – are seeing later activity, suggesting that other factors such as a decline in available food are also in play.

The research – which also involved scientists from the Centre for Ecology and Hydrology, the British Trust for Ornithology, Butterfly Conservation, and Science and Advice for Scottish Agriculture – was published in the journal Global Change Biology.