How will climate change affect Norfolk's wildlife?

It may not feel like it when a north-east wind drives in off the North Sea, but with the exception of the incredibly cold winter of 1962/63 snow cover lasting several weeks has been exceptionally rare over the last century.

Increasing average temperatures have now pushed autumn deep into December and spring is ready to burst forth as February comes to a close. Although many gardeners and early nesting blackbirds (keen to miss the rush) are often caught out in late March by a brief ‘Arctic blast’.

In the UK we are beginning to become acquainted with 12 degrees Celsius in January, but this mild winter weather is affecting places that really should be shivering in minus four and under several feet of snow.

Recently in the news it was reported that Eastern Poland experienced 16 degrees, the highest temperature ever recorded there in January.

Barely any snow has fallen on the Alpine ski slopes, and much of it under 2,000 feet has already melted.

Glaciers are retreating evermore quickly and mountain marmots are emerging from hibernation in January!

One would think that our wildlife thrives in much milder winter weather, and it is true to say that in some respects it does.

In the UK, non-migratory birds can struggle in cold weather and species such as Cetti’s warbler and Dartford warbler can have their populations almost annihilated by a harsh freeze, particularly if it comes late in the season.

Overwhelmingly our native wildlife has evolved to endure months of cold and snowy weather.

Some species, such as shrews and voles, have a higher winter survival rate in Scandinavia than in our own warmer, maritime climate.

Presumably living among vegetation under a layer of snow is more comfortable and forms a cover from predators.

Hibernating hazel dormice, hedgehogs and bats do better in the colder winters, as warm spells can rouse them from slumber and forces them to burn up precious fat reserves.

The brown rat, a non-native species that probably originated in India, will now continue to multiply through the winter, and along with the grey squirrel, is having an increasingly detrimental effect on our small bird population.

European otters are able to successfully hunt under a layer of ice in more northern latitudes – in Britain their obvious comfort with our balmier winter climate has led some to happily pup in mid-January.

Another animal that is accustomed to bearing young in winter is the grey seal, a relic of the Ice Age that seems a little out of place on the coast of Norfolk.

The pups are born on our sandy beaches in a covering of white fur, camouflage better suited to a backdrop of ice-floes and snowfields.

Our other seal species, the harbour seal, has summer pups and not surprisingly they are brown.

The white camouflage of mountain hare and ptarmigan is advantageous on the high tops of the Cairngorms, but on the lower slopes its purpose has been lost and can prove a serious liability.

Lowland stoats dressed in ermine fur are almost unheard of now, and even in Scotland they are seldom seen. When an individual does don a snow-white coat, they glow against the brown and beige of a British winter.

The consequences of our increasingly tame winters are not just an issue for animals and birds; many of our native plants prosper from a good hard winter too.

Yellow-rattle, often referred to as the meadow-maker, is semi-parasitic and prevents grass growth becoming too vigorous, thus providing space for other flowering plants.

The yellow-rattle seed will only germinate if it experiences a freeze and as an ‘annual’ it can disappear completely from an area without a good touch of ground frost.

Dormancy for many native flower seeds is broken not by a rise in temperature, but a drop. The season’s cycle of frosts, freezing then thawing, softens a seed’s tough shell allowing it to take up water. This is known as stratification, or cold treatment.

Even plants with tiny seeds rely on periods of prolonged cold, and many of the UK’s native trees and shrubs require a good dose of stratification, particularly those with large tough pips such as hawthorn and buckthorn.

The climate of the British Isles has fluctuated over tens of thousands of years and most of our native wildlife has evolved to deal with its peculiarities, however, the rate at which climate change is occurring and the rapid increase in average temperatures will challenge our natural world.

The Norfolk Wildlife Trust believes it is essential to mitigate by ensuring that our environment can sustain substantial and strong populations in a variety of protected and connected habitats.

This, it is hoped, will keep our native species robust enough to meet any future climate challenges.

With our changing climate and continuing pressures on the environment, by joining Norfolk Wildlife Trust you can help us protect and connect nature in your local area, helping it prosper for future generations to enjoy.