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What Is Phenology?

what is phenology bluebells

Around this time of year, you might come across the term ‘phenology’. But what does it mean, and why is it important?

For centuries. man has noticed the way the timing of natural events, such as bird migration, blossom flowering or leaves falling, can change annually. Many of us, after all, look out for the first snowdrops of the year, the first swallow or the first cuckoo. Phenology looks at these timings in a structured way to see whether annual changes in climate or habitat affect them.

What is phenology snowdrops

The First Phenologists

The first person we know of to record the timing of natural events in a consistent way was landowner Robert Marsham. He lived in Norfolk and began recording in 1736. For over 60 years he recorded 27 different signs of spring, including budding leaves and emerging insects. One of his correspondents was the better-known Gilbert White, who also made similar observations.

Incredibly, subsequent generations of Marsham’s family continued this record-keeping until 1958. This continuity has provided a wealth of information for scientists as they study the effects of changes in climate on the natural world.

Phenology Develops

Botanist Charles Morren first applied the term ‘phenology’ to this study in the mid-1800s, although it was a long time before it entered common usage.

The Royal Meteorological Society instigated the next main development. From the late 19th century, they organised volunteers to make seasonal observations across the British Isles. This was sadly discontinued in 1958, but over 50 years of data clearly showed a strong relation between temperature differences and the annual timing of events in the life cycles of the species monitored.

A number of passionate individuals then carried on making their own observations and contributed to the scientific record after the scheme ended.

what is phenology willow catkins

Citizen Science and Phenology

Fortunately, in 1998 biologist Tim Sparks began a pilot scheme to restart national recording. In 2000, his Centre for Ecology and Hydrology started working with the Woodland Trust on a new national citizen science monitoring scheme called Nature’s Calendar. Anyone can add a record of the first time each year they see a certain species or monitor the changes in certain plants as the year progresses.

The species recorded are all reasonably common across the UK (in both urban and rural settings), are easy to recognise and respond to changes in temperature. The website has a handy list of the species to look for, which include birds, plants, insects, fungi and amphibians. There is also an interactive map that shows what has been seen where and when going back to 2012.

what is phenology swallow

Phenology and the Future

Phenology is a hugely important science and has become more so as the impacts of the climate crisis become more apparent. Because no species exists in isolation, finding out how temperature changes affect species and natural events means we can look at possible consequences for whole ecosystems.

For example, if climate change means that swallows arrive back in the UK from Africa earlier each year, but insects don’t emerge at the same pace, the swallows will be less and less successful at rearing young. If we understand these disparities, we can understand how climate change is having an impact.

The more long-term records we have, the better for robust science, so why no sign up to the Nature’s Calendar scheme this spring and start recording?