Snowdrops

Fantastic Phenology

As January gets into its stride, many of us start looking out for the first signs of spring. This might be the first snowdrops, or the first tree leaf buds. Later on, we might notice our first swallow or chiffchaff. Some of us may even keep a record of when these events occur each year. I’ve touched on the subject of phenology, as we call this study of the timing of nature’s annual events, before. But as climate change increasingly affects our planet, the subject is now more important than ever before.

The First Phenologists

Humans will have been aware of when to expect certain natural events for millennia. Even before we settled down to farm the land it would have been essential to know when particular animals were likely to leave hibernation or when the first migrating birds would return, or berries appear. However, the first person we know of to make a detailed annual record of events was Norfolk farmer, Robert Marsham. He kept a log of events such as leaf bud appearance and insect emergence for 62 years from 1736. He also corresponded with the more famous Gilbert White who made similar records. Marsham’s descendants carried on the tradition until 1958. This provided an incredibly valuable long-term record for scientists who can see how timings have changed over the centuries.

Bluebells fantastic phenology
Many people note when they see their first bluebells of the year

In the 19th century, the study of nature’s annual cycles gained a name, phenology. It also became less the preserve of gentlemen naturalists and more of a serious scientific subject. Late in the century, the Royal Meteorological Society began to organise an army of volunteers to make seasonal observations across the British Isles. This carried on until 1958. The data showed a clear relationship between rising annual temperatures and the timing of stages in various species’ life cycles. When the scheme ended, various individuals carried on keeping records to provide a measure of continuity.

Phenology and Citizen Science

Luckily, there is now a structured approach to gathering nationwide information once more. In 2000, the Centre for Ecology and Hydrology joined forces with the Woodland Trust to set up Nature’s Calendar. This brilliant citizen science portal allows anyone to register and log a number of seasonal events. These range from the first time they see a particular bird or flower, to the various changes certain plants undergo through the year. As with all citizen science projects there are huge advantages to getting the public involved. The project gets records from a much bigger area than the organising bodies alone could cover. A lack of financial and physical resources often limits research opportunities. Volunteers are increasingly important to providing the amount of data needed to produce robust science.  

Fly agarics
Autumn records are as important as spring ones; fly agarics are one autumn species to log

The project includes a range of bird, tree, shrub, grass, fungi, insect, amphibian and flower species and covers events throughout the year. Autumn events are particularly useful to help build information about climactic changes. Earlier records tended to focus more on spring, leaving gaps in researchers’ knowledge. To rectify this, you can record a number of autumnal firsts including the first fly agaric fungi, first horse chestnut fruits and first fieldfare.

Horse chestnut
The first horse chestnuts are another useful autumn record

Spring events to look for include the first swallows, frog spawn, wood anemones and orange tip butterflies. Tree developments are recorded all year, from first buds to the date they become completely bare. All the species covered have been chosen carefully using particular criteria. The aim is for year on year records that can be easily and accurately compared. All are widespread across the country, are easy to recognise, have been recorded in the past and exist in both urban and rural environments. Most importantly, all the species included clearly respond to changes in temperature between the seasons.

Frog spawn
Frog spawn is another classic sign of spring

The website has a wealth of information to get you started. You can pick any number of species, although some need to be ones you can check regularly for changes. This applies particularly to trees whose changes need logging throughout the year. Each species has a clear guide telling you what to record and when to expect to see certain aspects of its life cycle. The species records also detail how far back the project has records for. The project summarises results twice a year so that anyone can look back and compare events year on year. Best of all, there is an interactive map which lets you see exactly where and when seasonal events are happening across the UK.

Phenology and Climate Change

What was once simply an enjoyable annual exercise is now an extremely valuable tool for researchers looking at the effects of climate change on the species around us. A huge range of research projects have used Nature’s Calendar data, with many ongoing. As well as projects looking at single species’ responses to climate change, the data also forms part of the Met Office’s annual UK climate report. Other organisations also monitor annual life cycle changes to see how climate change is affecting them. Edinburgh’s Royal Botanic Garden, for example, has been running its current programme since 2002, although curator James McNab recorded flowering dates for a number of plants there during the 1850s. The present scheme monitors 156 species to see how their annual development has changed over time and how plants are responding to climate change.

Wood anemones
Wood anemones are one of our earliest spring flowers

But why does it matter when certain natural events occur each year and if they change? The problem is that because of the intricacies of ecological systems, one small alteration can have a huge knock-on effect. For example, caterpillars make up a large part of the diet of many passerine chicks. If caterpillars start emerging earlier each year and birds don’t adjust their nesting times to match, they risk losing out on a vital food source. This could affect how many chicks survive to fledging and therefore future population levels.

Great tit chick
Great tit chicks’ diet includes a lot of caterpillars

At the moment evidence suggests that many of our birds are keeping pace with change. The famous Wytham Woods great tits, have been studied for 75 years and now lay their eggs three weeks earlier than they used to, for example. Migrating birds, though, may find it harder to adjust their timings, being unaware of conditions on their breeding grounds while still far away.

Phenology for the Future

No species exist in isolation. Because of this, phenology is a hugely important science. Scientists can use it to find out which organisms are able to adapt to our changing climate and which aren’t. This may in turn enable conservationists to help those that aren’t keeping pace with rising temperatures.

So why not get involved this year and start recording the natural events you see around you?

Further Reading

The first stop for all things phenology is the wonderful Nature’s Calendar website. As well as being the portal for recording your sightings, it is full of information about the topic. There is a look at the history of phenology, an explanation of what they record and why, and lots of information about the many projects that use Nature’s Calendar data.

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