UK plants flowering a month earlier due to climate change – study

By Sam Russell, PA

Climate change is causing plants in the UK to flower a month earlier on average, risking the collapse of some species, a study suggests.

Researchers analysed more than 400,000 observations of 406 plant species in a citizen science database with records going back to the 18th Century.

The team, led by Cambridge University, identified that the average first flowering date from 1987 to 2019 was a month earlier than the average first flowering date from 1753 to 1986.

The period coincides with accelerating global warming caused by human activity.

Lead author Professor Ulf Buntgen, from Cambridge’s Department of Geography, said: “The results are truly alarming, because of the ecological risks associated with earlier flowering times.

“When plants flower too early, a late frost can kill them – a phenomenon that most gardeners will have experienced at some point.

“But the even bigger risk is ecological mismatch.

“Plants, insects, birds and other wildlife have co-evolved to a point that they’re synchronised in their development stages.

“A certain plant flowers, it attracts a particular type of insect, which attracts a particular type of bird, and so on.

“But if one component responds faster than the others, there’s a risk that they’ll be out of synch, which can lead species to collapse if they can’t adapt quickly enough.”

The dataset, called Nature’s Calendar, is maintained by the Woodland Trust.

It includes observations of seasonal change as recorded by scientists, naturalists, amateur and professional gardeners, as well as organisations such as the Royal Meteorological Society.

“We can use a wide range of environmental datasets to see how climate change is affecting different species, but most records we have only consider one or a handful of species in a relatively small area,” said Prof Buntgen.

“To really understand what climate change is doing to our world, we need much larger datasets that look at whole ecosystems over a long period of time.

“Anyone in the UK can submit a record to Nature’s Calendar, by logging their observations of plants and wildlife.

“It’s an incredibly rich and varied data source, and alongside temperature records, we can use it to quantify how climate change is affecting the functioning of various ecosystem components across the UK.”

For the current study, researchers used observations of the first flowering date of trees, shrubs, herbs and climbers, in locations from the Channel Islands to Shetland, and from Northern Ireland to Suffolk.

The researchers classified the observations in various ways: by location, elevation, and whether they were from urban or rural areas.

The first flowering dates were then compared with monthly climate records.

To better balance the number of observations, the researchers divided the full dataset into records until 1986, and from 1987 onwards.

The average first flowering advanced by a full month, and is strongly correlated with rising global temperatures.

Prof Buntgen said that if global temperatures continue to increase at their current rate, spring in the UK could eventually start in February.

Co-author Professor Tim Sparks, of Cambridge’s Department of Zoology, said: “Continued monitoring is necessary to ensure that we better understand the consequences of a changing climate.”

The research is published in the journal Proceedings of the Royal Society B.