The lichen are coming - thanks to Britain's cleaner air

RARE SPECIES of lichen which have disappeared from much of Britain are making a dramatic comeback thanks to cleaner air.

One survey at Kew gardens in west London has found that the number of lichens growing there has more than doubled since 1970, when scientists recorded just 30 species.

The study has so far identified 72 species and is expected to find far more when it is finished this summer. Researchers identified one endangered species which has been seen only 13 times in the past 40 years.

The lichen, Cyphelium notarisii, was found growing on a bench at the botannical gardens, which has now been bolted to the ground to protect its valuable stowaway from being unwittingly removed and cleaned off.

Sandra Bell, a botanist at Kew, said the return of rare lichens to many urban sites shows that certain forms of air pollution are less of a problem than they once were. "Lichens are particularly sensitive to air pollution and so are valuable indicators of air quality."

Lichens are not a single organism but the result of a unique relationship between different types of algae and fungi. The alga, which is a plant, converts sunlight into chemical energy, and the fungus in return provides vital nutrients and physical protection for the alga.

Britain has about 1,700 types of lichen, which can grown on rocks and tree bark. Industrial pollution, however, has severely curtailed their range. In 1820, a lichen survey at Kew recorded 165 species. The number recorded in 1906 was just 15.

William Purvis, head of lichenology at the Natural History Museum in London, said that lichens are particularly susceptible to acid rain, caused by the release of sulphur dioxide by open fires and coal-fired power stations.

Since the Clean Air Act of 1956 - intended to combat London smogs - and the closure of many coal-fired power stations, levels of sulphur dioxide released in Britain have fallen significantly, allowing lichens to re- colonise old haunts. Dr Purvis said: "UK emissions of sulphur dioxide have decreased by 80 per cent since 1962. As a result there has been a remarkable increase in lichens. Every year we find new species."

The demise of lichen-covered trees in Victorian Britain was responsible for a famous cases of evolution in action - the demise of the mottled form of the peppered moth in favour of its black, melanic mutant.

Scientists found that the mottled form was perfectly camouflaged against predators when resting on a lichen-covered tree. When lichens disappeared, it was the relatively rare melanic form that had a better chance of not being seen by birds.

PROMOTED VIDEO
Have you tried new the Independent Digital Edition apps?
News
ebookA unique anthology of reporting and analysis of a crucial period of history
Arts and Entertainment
Standing the test of time: Michael J Fox and Christopher Lloyd in 'Back to the Future'
filmReview: A week late, Secret Cinema arrives as interactive screening goes Back to the Future
Travel
travel
Arts and Entertainment
Sydney and Melbourne are locked in a row over giant milk crates
artCultural relations between Sydney and Melbourne soured by row over milk crate art instillation
Arts and Entertainment
Adèle Exarchopoulos and Léa Seydoux play teeneage lovers in the French erotic drama 'Blue Is The Warmest Colour' - The survey found four times as many women admitting to same-sex experiences than 20 years ago
filmBlue Is The Warmest Colour, Bojack Horseman and Hobbit on the way
Arts and Entertainment
Preparations begin for Edinburgh Festival 2014
Edinburgh festivalAll the best shows to see at Edinburgh this year
News
Two giraffes pictured on Garsfontein Road, Centurion, South Africa.
i100
News
Kenny Ireland, pictured in 2010.
peopleBenidorm, actor was just 68
Environment
View from the Llanberis Track to the mountain lake Llyn
Du’r Arddu
environmentA large chunk of Mount Snowdon, in north Wales, is up for sale
News
i100
Arts and Entertainment
arts + ents
News
Morrissey pictured in 2013
people
Independent
Travel Shop
the manor
Up to 70% off luxury travel
on city breaks Find out more
santorini
Up to 70% off luxury travel
on chic beach resorts Find out more
sardina foodie
Up to 70% off luxury travel
on country retreats Find out more
Latest stories from i100
Have you tried new the Independent Digital Edition apps?
Independent Dating
and  

By clicking 'Search' you
are agreeing to our
Terms of Use.

iJobs Job Widget
iJobs General

SEN Learning Support Assistant

Negotiable: Randstad Education Birmingham: LSA's required! West Midlands

MLD Teacher

Negotiable: Randstad Education Birmingham: MLD teachers required West Midlands...

Media Studies Teacher

Negotiable: Randstad Education Hull: Randstad Education are recruiting for a M...

History Teacher

£90 - £120 per day: Randstad Education Hull: Randstad Education are looking fo...

Day In a Page

Dress the Gaza situation up all you like, but the truth hurts

Robert Fisk on Gaza conflict

Dress the situation up all you like, but the truth hurts
Save the tiger: Tiger, tiger burning less brightly as numbers plummet

Tiger, tiger burning less brightly

When William Blake wrote his famous poem there were probably more than 100,000 tigers in the wild. These days they probably number around 3,200
5 News's Andy Bell retraces his grandfather's steps on the First World War battlefields

In grandfather's footsteps

5 News's political editor Andy Bell only knows his grandfather from the compelling diary he kept during WWI. But when he returned to the killing fields where Edwin Vaughan suffered so much, his ancestor came to life
Lifestyle guru Martha Stewart reveals she has flying robot ... to take photos of her farm

Martha Stewart has flying robot

The lifestyle guru used the drone to get a bird's eye view her 153-acre farm in Bedford, New York
Former Labour minister Meg Hillier has demanded 'pootling lanes' for women cyclists

Do women cyclists need 'pootling lanes'?

Simon Usborne (who's more of a hurtler) explains why winning the space race is key to happy riding
A tale of two presidents: George W Bush downs his paintbrush to pen father’s life story

A tale of two presidents

George W Bush downs his paintbrush to pen father’s life story
Restaurateur Mitch Tonks has given the Great Western Pullman dining car a makeover

The dining car makes a comeback

Restaurateur Mitch Tonks has given the Great Western Pullman dining car a makeover
Gallery rage: How are institutions tackling the discomfort of overcrowding this summer?

Gallery rage

How are institutions tackling the discomfort of overcrowding this summer?
Louis van Gaal has £500,000 video surveillance system installed to monitor Manchester United players

Eye on the prize

Louis van Gaal has £500,000 video surveillance system installed to monitor Manchester United players
Women's rugby: Tamara Taylor adds fuel to the ire in quest to land World Cup

Women's rugby

Tamara Taylor adds fuel to the ire in quest to land World Cup
Save the tiger: The day America’s love of backyard tigers led to a horrific bloodbath

The day America’s love of backyard tigers led to a horrific bloodbath

With only six per cent of the US population of these amazing big cats held in zoos, the Zanesville incident in 2011 was inevitable
Samuel Beckett's biographer reveals secrets of the writer's time as a French Resistance spy

How Samuel Beckett became a French Resistance spy

As this year's Samuel Beckett festival opens in Enniskillen, James Knowlson, recalls how the Irish writer risked his life for liberty and narrowly escaped capture by the Gestapo
We will remember them: relatives still honour those who fought in the Great War

We will remember them

Relatives still honour those who fought in the Great War
Star Wars Episode VII is being shot on film - and now Kodak is launching a last-ditch bid to keep celluloid alive

Kodak's last-ditch bid to keep celluloid alive

Director J J Abrams and a few digital refuseniks shoot movies on film. Simon Usborne wonders what the fuss is about
Once stilted and melodramatic, Hollywood is giving acting in video games a makeover

Acting in video games gets a makeover

David Crookes meets two of the genre's most popular voices