Once thriving wildlife populations are on the verge of extinction across the region, according to a startling new nature report.

Conservation experts say the outlook is “bleak” for nearly a third of native UK species, revealed to have been in stark decline for the last 50 years.

The first ever State of Nature Report, compiled by scientists from 25 wildlife organisations, paints a sombre picture of the impact environmental change has made on the habitats of certain species - the most vulnerable of which feature on a new “Watchlist” indicator.

The East of England has been labelled “a region of extremes”, containing pockets of extremely rich biodiversity like Minsmere, Hickling Broad, Weeting Heath and Wicken Fen, but also experiencing population decline across huge swathes of countryside.

Experts calculate that 81% of turtle doves have been lost in the East of England since the 1970s - with the average number of summer breeding attempts halved in that time. Meanwhile, the lowland corn bunting bird has fallen in number by almost a quarter in recent decades.

The decline of three more species - the skylark, the brown hairstreak butterfly and the barn owl - has been related to agricultural changes affecting nesting and food, while one in four species of flowering plants is under threat in lowland semi-natural grassland and heathland habitats, partly due to “inadequate or inappropriate land management”.

There are a number of success stories, with bitterns and otters among those species fighting back, but some species could be lost altogether within the next decade, according to the RSPB’s senior farmland conservation officer in the East, Simon Tonkin, who said: “Farmland bird numbers overall have halved since 1970. Imagine turning the volume of birdsong in today’s farmland up twice as loud - that’s what our countryside sounded like 40 years ago.

“The 25 conservation allies who came together for the first time ever to produce this report provide a loud and clear message to decision makers and policy makers, urgent change is needed and adequate funding for wildlife friendly farming is vital to stop our quickly vanishing wildlife.”

Despite UK woodland growing in size, mainly due to conifer planting, woodland birds have been declining since the 1970s, and butterflies since the 1990s.

Nightingale numbers in the East of England reportedly halved between 1995 and 2010.

The outlook for the willow tit is even gloomier, while the Norfolk Bird Atlas reports only 25 to 50 pairs of breeding lesser spotted woodpecker in the county.

Julian Roughton, chief executive of Suffolk Wildlife Trust, said: “The general picture is bleak in terms of declines and losses but there have been some positives, sometimes as a result of new habitat creation.

“The problem of decline and loss could be put down to climate change and also fragmentation of habitat. It’s a complex area and there are often several causes.

“We need to create space for nature. Where there is fragmentation, habitats are very vulnerable. If we can connect them it would allow space for habitats to become more robust and, in a sense, look after themselves.

“Landscape connectivity gives populations a better chance of surviving other factors like very poor winters and cold springs, which we have seen in recent years.

“Our region is very rural and rich with farmland. We still need to do more to bring populations back. We are seeing an increase in public interest - with people bringing back meadows, creating new woodland and making their own gardens a home for wildlife.”

Recent habitat projects have aided population growth for a variety of wildlife, and Suffolk currently accommodates 5.3% of the nation’s lowland heathland resource, with Sutton and Hollesley Common representing one of the largest continuous areas of Sandlings heathland in existence.

Meanwhile, the breckland heaths is home to more than two-thirds of the country’s stone curlew population, and the Suffolk coast has recorded recent booms in numbers of endangered nightjar.

However, species like woodlark and the Dartford warbler have fallen.

On the coast, the report identifies the importance of seabird habitats and highlights species for which Eastern England has an important role to play in conserving.

Phil Pearson, RSPB senior conservation officer, said beach-nesting little terns had fallen 25% in the past, with more people using the beaches where they like to breed, as well as changes in habitat suitability and sea-level rise, and increased storm events reducing the amount of available breeding habitat.

Mr Pearson added: “Whilst the issues affecting little terns are big, we know what measures are required to manage the colonies effectively and where we get it right large numbers of chicks can be produced.”

On the Norfolk coast, the Winterton Dunes colony last year produced 410 little tern chicks from 197 pairs.

Experts also say that many characteristic freshwater species have declined over the last 50 years, including the Atlantic salmon, water vole and the aquatic plant frogbit. Some, such as the freshwater pearl mussel, are threatened with global extinction.

The report is being launched by Sir David Attenborough in the same month researchers from the University of East Anglia (UEA) released findings in the Terrestrial Biodiversity Climate Change Impacts Report Card, which claimed East Anglia’s coastline and wildlife were under threat from climate change and extreme weather.

The benefit of habitat creation:

At least 700 hectares of reedbed have been recreated across the country over the last 20 years, mostly inland and safe from sea level rise which threatens sites around the East Anglian coast.

Bittern numbers were down to just 11 booming males in 1997 but topped 100 in 2011 for the first time since records began.

The RSPB believes new reedbeds have aided the recovery of many specialist species, such as the bittern.

New reedbeds have been created at Lakenheath Fen and at the Suffolk Wildlife Trust reserve at Hen Reedbeds, near Southwold.

The State of Nature Report claims that a number of areas in the East of England are home to the last remaining numbers of certain species:

South Essex and the Thames gateway supports one of only five remaining meta-populations of shrill carder bees in the UK.

The yellow horned poppy is a nationally scarce species of which a fine population may be found at Cley and along the eastern end of Blakeney Point in Norfolk.

The Fens in Broadland are the last habitat in the UK of the magnificent swallowtail butterfly, whose larvae feed exclusively on rare milk parsley plants.