Year of extreme weather creates confusion for Britain’s flora and fauna


It was a year of extremes as far as the weather was concerned: pounding rain, violent summer storms, some mild winter months and periods of searing sunshine.

An annual audit of how this year’s weather has affected flora and fauna in the UK has concluded that it was, to say the least, a challenging 12 months.

Warm winter months was good news for some moths and birds and it was a bumper spring for blossom and a “mast” year (a term for a bountiful season) for nuts and berries.

But it was not such a good 12 months for many seabirds, according to a survey from the conservation charity the National Trust, and many slopes that are usually bright with heather were duller than usual.

The trust, which each December looks back at how the weather has affected flora and fauna at its sites, warned that the climate emergency was clearly leading to more erratic weather patterns and hitting Britain’s animal and plant life.

It began well for birds such as the lovely Dartford warbler, which appears to have enjoyed the mild winter. Just 11 pairs survived after two particularly cold winters in the 1960s and its comeback was hit again by the “beast from the east” in 2018 but it had a good 2020 and one of the warblers was spotted on the Long Mynd in Shropshire for the first time in 20 years.

Dartford Warbler

The ring ouzel, a bird of the uplands, also thrived in the milder conditions. A relative of the blackbird, most spend winter in the Mediterranean but each year a few stay in the UK – and one was spotted at Cwm Idwal in north Wales.

The mild winter and early warm weather resulted in many fruit trees coming into blossom two weeks earlier than normal. At Ham House in south-west London, the blossom bloomed in a pleasingly regular sequence – the apricot in a very sheltered spot first, followed by peaches, cherry, then plum well into the spring.

A warm spring led to sightings in the New Forest in southern England of silver-studded blue and small heath butterflies flying up to a month ahead of schedule. A marsh fritillary was also spotted at The Coombes in Wiltshire, a steep-sided dry stream valley on the edge of the Marlborough Downs, for the first time.

Silver-studded blue butterflies

Warm winds from the continent brought in impressive numbers of migrant moths in the summer. Among these was the Clifden nonpareil, one of the UK’s largest moths, which was recorded on a beech tree at Cliveden House on the Buckinghamshire/Berkshire border, 250 years after it was first recorded there.

It wasn’t all good news for insects. Only modest numbers of butterflies such as the brimstone and large skipper were recorded. A dearth of cold winters may be allowing their parasites and predators to prosper.

June was brutal for little terns at Long Nanny in Northumberland when storms washed nests away. The seabird has been in serious national decline since the 1980s, with fewer than 2,000 pairs now left in the UK.

The colony at Strangford Lough in Northern Ireland also struggled, with numbers of sandwich, arctic and common terns all lower than in 2019 due to predation and high tides.

Long dry periods in the summer hit some flora badly. Ash trees were affected by a prolonged warm and dry spell, which put them under additional stress, making them more susceptible to ash dieback. About 40,000 trees are being removed from National Trust land this year because of the disease.

Dying ash trees

Heather, already under stress from drought conditions in 2019, was more susceptible to dieback caused by the heather beetle. The beetle dies off in cold winters, but with this year’s warm and wet winter it continued to feed on the moorland plants, putting them under severe pressure and killing them off, affecting swathes across north Wales.

The mild and steady conditions in early autumn resulted in a “mast year” for trees, shrubs and hedgerows, with an abundance of acorns, conkers, sloes and rowan berries.

Ben McCarthy, the head of conservation and restoration ecology at the National Trust, said the terns were a good example of creatures being hit by extreme weather and the climate crisis. “All our breeding terns are in trouble,” he said. “It was heart-breaking to see so many nests washed away by summer storms.

“With sea levels rising, the area available for terns to nest on is being squeezed. When several years of summer storms are thrown in, the terns cannot raise enough chicks to keep the population going.

“Changes to the seasons and changeable weather can play havoc with our wildlife, knocking the delicate balance of nature out of kilter, with serious knock-0on effects for us all.”


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