by Kate Lewthwaite, Woodland Trust

 

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Although March 20^th signals the official start of spring this year, the Woodland Trust’s Nature’s Calendar citizen science survey received some astonishing pre-Christmas sightings and has also seen some spring events up to six weeks earlier than average.

The project asks volunteers to spot the signs of the changing seasons across the UK and is used by scientists to assess the impact of climate change on wildlife in the UK.

December 2015 was the mildest since UK-wide records began in 1910. I saw my first daffodil in flower in the garden on Boxing Day, which was the earliest I have ever seen. Here is an example of one report from a recorder: 

Sally Cunningham, from Leicester, got in touch just before Christmas to say:

"The following were all in flower yesterday, the winter solstice. Lesser celandine, wild primrose, cow parsley and breaking buds on a newly planted hawthorn... All our blue tits, blackbirds and robins are pairing up but the thrushes aren't singing yet... and if the lawn was dry enough I should cut it!"

Temperatures in January and February were less exceptional but when they are added to December to give the overall MET office assessment of ‘winter’ it ranks it as the third warmest since 1910. 

Here is a comparison of a selection of records looking at spring 2016 (records to date) compared to spring 2015 and also spring 2001 ( a year we use as a ‘benchmark’ due to its spring temperatures being close to the long-term average)

Event	Compared to 2015	Compared to 2001
Blackthorn first flower	6 weeks earlier	6 weeks earlier
Hawthorn first leaf	5 weeks earlier	6 weeks earlier
Bluebell first flower	2-3 weeks earlier	4 weeks earlier
Nest building blackbirds	No difference	1 week earlier
Nest building bluetits	No difference	No difference
Ladybird first sighting	No difference	No data
Red- tailed bumblebee first sighting	No difference	No data

For trees and plants 2016 has been exceptionally early, perhaps because they have been able to take  most advantage of the cumulatively mild conditions. Breeding birds use other cues to start nesting such as day length that may explain their lack of response. The insect records may not be dramatically different because they would be more impacted by temperatures in February which were less exceptional.

These findings beg the question ‘so what’? Nature’s Calendar has data that traces spring’s arrival since the 17^th century, but in the last 30 years we have seen a marked advance in the appearance of many spring signs, which is what we might predict as a result of climate change. Getting ahead isn’t necessarily the best policy for nature: hard frosts or snow that follow mild spells can damage delicate plant tissues and insects caught out in the cold could also suffer. There is also evidence that species are responding individually to climate change and so food chains could eventually become ‘out of synch’ for instance if breeding birds cannot change their timings to adapt to changing peak invertebrate availabilty.

 

Can you help play your part in this ongoing research and contribute to tracking the signs of spring with Nature’s Calendar? www.naturescalendar.org.uk

 

Image Credits

WTPL / Phil Lockwood

Sally Cunningham, 'lesser celandine'