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[guardian.co.uk > News > World news > China]

China braces for more floods as heavy rains predicted
Forecasters warn water levels could rise further and cause more destruction as rescue teams continue search for survivors

Tania Branigan in Beijing and agencies
guardian.co.uk, Wednesday 11 August 2010 09.07 BST
Article history

{A controlled explosion is carried out to remove debris damming a river, in order to release flood waters in Zhouqu, China. Photograph: Keystone USA-Zuma/Rex Features}

Survivors of the landslides in north-western China are braced for further misery as forecasters predict more heavy rains.

At least 1,117 people died when mud and debris swept through Zhouqu, in Gansu province, late on Saturday night and more than 600 are missing. There is little hope of finding more survivors among what are thought to be the hundreds who were buried alive in metres of sludge.

The 10,000 rescue and relief workers are continuing to search for bodies but attention is turning to the threat of disease.

Crews in protective suits have sprayed chemical disinfectant across the ground and over machinery. State media has reported numerous cases of dysentery and warned of a serious shortage of drinking water, with most local sources destroyed or polluted.

One survivor, Yang Jianjie, gave a graphic description of the moment landslides engulfed the county seat. He stood hand in hand with his parents and grandfather on the roof of their home as the tide of mud swept towards them – only to be separated as the two-storey building collapsed.

"Mud and rocks slammed my parents and grandfather in the face and buried them," the 20-year-old told the China Daily newspaper.

The Bailong river burst its banks, sending water coursing through the narrow valley.

Shen Si watched as troops dug at the site of her buried home to reach the bodies of her relatives. "My mother and father were in their 60s and my younger brothers, all three of them, are buried here in our house still," she said.

Torrential rains on Saturday night triggered the landslide and flooding. Experts have said 2008's earthquake in neighbouring Sichuan loosened rock faces. But government reports show that officials had been warning for years that deforestation and rapid hydro development were increasing the risk of landslips in the area.

"This has happened before. The government knew it could happen again and did nothing to prevent it," said a farmer called Yang, who did not want to give his full name. Five of his relatives were buried in the mudslide and he was digging to find them.

There are concerns the barrier lake that has formed could overflow or burst, especially if there is further rain. Soldiers have been blasting explosives at the barrier to clear debris and help reduce water levels. Tens of thousands of people have been evacuated.

Separately, a Chinese paper reported that residents along the north bank of the Yellow river in Henan province fear for their lives after heavy rain gouged holes in a newly built flood control dam.

"Every time when we hear the rain is coming we are too scared to sleep in the evening," a party secretary from one village was quoted as saying in Dahe Daily.

Wang Dayong, head of the Yellow River Affairs Bureau of Yuanyang, acknowledged the dam had been damaged but told the Global Times reports were exaggerated and the structure was strong enough.


[guardian.co.uk > Environment > Mining]

Scottish gold mine in doubt
Planners at Loch Lomond national park say application to mine gold should be refused after objections from conservationists

Severin Carrell, Scotland correspondent
guardian.co.uk, Tuesday 10 August 2010 17.30 BST
Article history

{Looking up the river towards the Cononish mine which sits just inside the Loch Lomond national park. The park's director of planning has recommended that a proposal to mine its gold be rejected. Photograph: Murdo Macleod for The Guardian}

Plans to mine more than £110m worth of gold in the Scottish Highlands have hit a serious setback after planners at Loch Lomond national park today said the application should be refused.

With gold prices soaring, the mining company Scotgold wants to dig out 700kg of gold and 17 tonnes of silver a year over the next decade from an unworked mine called Cononish, which sits near Tyndrum, just inside the north-eastern boundary of the national park.

The proposal has been enthusiastically supported by local councillors and appeared to have been positively received by the national park. But following objections from conservationists and countryside groups, Gordon Watson, the park's director of planning, has recommended the proposal be rejected.

The park's planning committee is due to visit the site next week to finally decide on the application, which has taken three years and nearly Aus$8m (£4.6m), raised from private Australian investors, to develop.

In a report to the committee, Watson said the site, which would cover about 39 hectares near Ben Lui mountain with a large waste tailings dam up to 30m high and a 100m-long rock-crushing plant, would cause "acute" and "significant" landscape and environmental damage.

He disputed Scotgold's claims it would create 52 jobs and a new local industry selling Scottish gold jewellery, with £50m invested in the local economy. Gold prices – currently at a near record high of $1192 (£757) a Troy ounce – were too volatile, he claimed.

"Any overall economic gain is extremely difficult to quantify, may be less than projected and is highly vulnerable to market conditions for the price of gold," he said. "The longer-term economic legacy is likely to be marginal, while the long-term landscape impacts will certainly not be."

Watson said the act to set up the Loch Lomond and the Trossachs national park in 2000 made clear that conserving the environment and Scotland's natural heritage outweighed any economic and social benefits the mine would bring.

Scottish Natural Heritage (SNH), the government's main conservation agency, warned the mine could significantly threaten salmon stocks and waters in the River Tay, which is heavily protected under conservation legislation.

Climbing and wilderness campaigners, led by the John Muir Trust and the Mountaineering Council of Scotland, complained about the damage to the landscape. They argued it would significantly affect the beauty of nearby mountains climbed each year by up to 15,000 people – a position endorsed by the planners and SNH.

However, the Scottish Environment Protection Agency, which has statutory duties to protect water quality, said it was satisfied there was no pollution risk. It had initially raised anxieties about the potential threat of leakage.

Watson criticised Scotgold's environmental assessment, claiming the firm had overstated the impact of old mine workings at the site, understated the long-term damage of the permanent tailings dam, and had not "convincingly proven" that its restoration plans for the dam would be effective.

Chris Sangster, Scotgold's director, said he was "a bit shell-shocked" by Watson's recommendation. "We worked very closely with the parks authority and the other statutory bodies for a long period of time, and we certainly believe the project has immense benefits," he said.

Sangster said he was puzzled Watson was raising doubts about long-term gold prices.

"We're in the mining business: we wouldn't succeed with a project that we don't think is economic," he said. Watson had exaggerated the landscape impacts, he added. The mine would be "transient" and the remodelled waste dam would blend well into the surrounding land. "We don't think we're at odds with the aims of the national park, which is to conserve and enhance its natural and cultural aspects; we think it will enhance the cultural aspects of the park."

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[guardian.co.uk > News > UK news]

Cotswolds 'green' motorway services gets thumbs-up from planners
Eco-friendly area in natural beauty spot to feature electric charging points, ban on fast food giants and locally sourced produce

Robert Booth and Francis Grove-White
guardian.co.uk, Tuesday 10 August 2010 19.49 BST
Article history

{A more pleasant experience may await drivers on the M5 with the Gloucester Gateway motorway services but environmentalists say it will bring even more traffic to the area. Photograph: Barry Batchelor/PA}

With a grass roof on the petrol station and a vegetable patch beside the coach park, the concept for Britain's greenest motorway services may seem beset by contradictions. But planners have approved designs for the £35m Gloucester Gateway project which aims to reinvent the motorway pitstop for the carbon-conscious generation.

The new services, nestling on the edge of the Cotswolds between junctions 11a and 12 on the M5, will sell fuel to thousands of cars a week while at the same time trying to drive down carbon emissions by banning fast food chains and sourcing most of its food supplies from within a 30-mile radius.

The application has been fiercely opposed by local environmental campaigners, who fear it will scar the neighbouring designated area of outstanding natural beauty and warn that, far from reducing the environmental impact of the motorways, it will encourage more people to drive.

The developer, Westmorland – which already runs an independent services at Tebay on the M6 in Cumbria – says the project, due to be completed in 2013, is required under Department for Transport guidelines and will use a fifth of the energy of a conventional service area.

The car parks have been designed to allow for charging points for electric vehicles and the filling station can be adapted to bio-fuel pumps in the future. Inside, fast food concessions such as Burger King or McDonald's will be banned and instead the centrepiece of lunch will be a roast from a local farm. To avoid the anonymous atmosphere of many service stations it is designed to stress the attractions of the Gloucestershire area. The timber-framed buildings will be built of douglas fir from the nearby Forest of Dean and will be a "homely and rural" design.

"In Britain we are reliant on road transport so we have to provide service stations," said Sarah Dunning, chief executive of Westmorland. "We don't feel responsible for that. But we can say to ourselves what kind of experience do we want to create. We don't have franchises so instead of a Kentucky Fried Chicken and Marks & Spencer, we have cafes with home-made food.

"Whatever there is a lot of in Gloucestershire there will be a lot of on the menu. Everything will be fresh and made on the site. In the sandwiches it will be local goat's cheese, not of unknown origin, with artisan chutney in there as well."

The developer claims 70% of all meat, dairy, eggs and bakery products will be sourced from the region. The shops will be stocked by the produce of at least 60 local and regional businesses while 10% of the energy will come from on-site renewable technologies. Staff will be bussed in to reduce car journeys and more than half of all catering and retail waste will be recycled or composted on site for use in the gardens.

"We are not decorating a normal petrol station," said Glenn Howells, the architect. "This is more fundamental. This is the best possible motorway service station with the present fuel systems but is also designed so we can react nimbly to changes in the available fuels."

But there is opposition. Some say the green claims for the project are no more than window dressing and the planning meeting, held at the Stroud council offices yesterday, was followed by acrimonious exchanges between environmentalists and the landowners and developers.

John Marjoram, a Green Party councillor, said he was very disappointed by the decision, and said while he "couldn't fault them on design, whatever you do to disguise it it's still a motorway service area". He said the project was akin to trying to design a more sustainable airport: "The bottom line is that there will be more planes in the sky."

Emissions produced in construction and increased emissions from vehicles slowing down, stopping and then setting off again needed to be taken into consideration. Opponents are considering seeking a judicial review of the decision, he said.

"I had lots of stick today, lots of swearing," said Michael Warner, a farmer who sold his land to the developer for the project. "But I know that in the future there will be thousands of people who will be able to stop there, get the views of the Cotswolds and experience the pleasure I have had farming here for decades."

The developer, a family-owned farming business based in Cumbria, has won plaudits for Tebay services. Radio DJ Stuart Maconie labelled it "the Keira Knightley of service stations", and it was named 2009 service station of the year by the website motorwayservices.info which gave it a top "five burger" ranking, even though there are no burger concessions. Instead there is a farm shop and duckpond.

But even the site's editor, Mark Goodge, has reservations about the claims being made for Gloucester Gateway.

"The concept of an environmentally friendly service area is, to some extent, an oxymoron," he said. "A lot of people may feel that the green label is an excuse to put up prices."

Westmorland insists it is acting in the best interests of the environment and local people. It has committed to donate a percentage of turnover to a charitable trust for local good causes, which should deliver around £500,000 a year for the next 20 years.

From groovy to grubby and back

When Britain's first motorway service station opened at Watford Gap on the M1 in 1959, the excitement was such that it was packed to capacity on its first day. Early designs tried to capture the feeling that motorway travel was a glamorous experience akin to flying. Travellers could dine with panoramic views over the M6 from the hexagonal tower at Forton services in Lancashire, while at Washington-Birtley on the A1M, motorists were invited to "step into another world" of sweeping futuristic decor and be waited on by miniskirted hostesses.

But as the roads filled up and fuel prices soared during the 1973 oil crisis, the prestige of motorway travel began to splutter. Restaurants became self-service, groovy interiors were replaced with wipe-clean surfaces and service areas earned a reputation as pricey and grubby. By the 1990s, signs of a revival had emerged. Food critic Egon Ronay turned his attention to standards, attacking the "pigswill" routinely purveyed. Operators began to realise that drivers would be more likely to pull over if they recognised the brands on offer and fast food chains moved in.

The last decade has seen a swing back towards the service station's upmarket roots with offerings from Marks & Spencer, Waitrose and expensive coffee chains.

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[guardian.co.uk > Environment > Endangered species]

To the circus: conservationists warn of elephant exodus from Laos
Once worshipped as gods, the endangered elephant population of Laos is under threat from a legal loophole

Fiona MacGregor
guardian.co.uk, Tuesday 10 August 2010 11.57 BST
Article history

{Mahouts (elephant keepers) are being offered incentives to conserve the elephant population of Laos. Photograph: David Longstreath/AP}

It may be known as the Land of a Million Elephants, but conservationists are warning that the imminent exportation of more than a third of Laos's remaining domesticated elephant calves to a Chinese circus could prove disastrous for the endangered species.

Once worshipped as gods, the animals are still considered sacred by many in Laos, but loss of habitat and tradition means there are now just 20 domesticated elephants under the age of 10 left in the country.

The agreement with the circus company will see seven of these youngsters, along with four older animals of breeding age, exported from the remote Thongmixay district, in Laos's Sayaburi province, to southern China this autumn.

Although Laos signed up in 2004 to the CITES international agreement against trading endangered wildlife, a loophole is being exploited. Elephants are being taken out of the country on "long-term loans" to zoos and circuses in foreign countries but are never returned.

With the most recent government estimates suggesting there are now as few as 600 wild and only 480 domesticated elephants left in the country, hopes for the survival of the species in Laos are pinned on breeding programmes involving the domesticated population. The loss of so many young elephants will place that under threat, the NGO ElefantAsia has warned. The group has official responsibility for the animals, having been charged by Laos's department of livestock to manage the Laos Elephant Care and Management Programme.

"We are very concerned to see so many elephants – especially young ones and females – being exported to foreign countries," said Sebastian Duffillot, co-founder of ElefantAsia. "The best and healthiest animals have been leaving the country steadily for several years despite existing laws condemning the export of live elephants."

Korea and China are the main destinations for the "loaned" elephants. Because elephants are privately owned, ElefantAsia has no mandate to prevent the animals leaving the country. "Laos needs to protect its elephants by any means if the country wants to keep a sustainable population," said Duffillot.

Although companies from these countries pay the animals' transport costs into the country, they often renege on paying return costs, leaving it impossible for the elephants' owners to take their animals home if and when their contracts eventually runs out. In one such example it is understood that 19 elephants were sent to Korean circuses in 2002/3, all of which have now been sold there and not returned to Laos.

It is understood the elephant handlers - mahouts - in this latest deal have been offered $150 dollars a month to work with their elephants in the Chinese circus. This represents a considerable income in Laos, where average earnings are just $30 a month.

Traditionally known as "Lane Xang", meaning "land of a million elephants", the working relationship between humans and elephants in landlocked Laos, one of the world's least developed countries, dates back 4,000 years. The rapid decline in numbers is due to a combination of habitat loss, poaching and animals being killed after threatening people and their property.

Elephants are still held in high esteem in Laos culture, where the religious mix of Buddhism and animism sees them considered sacred beings. Women bring their babies to be blessed by elephants, but the reality of life for the average domesticated elephant is far from divine. Most working elephants are used as labour in logging camps. Grim working conditions and long hours take a toll on their health as elephants are used to destroy the forest homes of their wild relatives.

ElefantAsia is keen to encourage mahouts to turn away from the logging industry and use their animals in sustainable, welfare-conscious tourism projects.

The organisation is involved in a number of breeding programmes including the recent launch of an innovative maternity leave scheme for elephants in which mahouts are given financial incentives and offered alternative work if they breed their elephants – a process which can take an elephant out of work for four years, with a two-year gestation period and a further two years spent nursing their baby.

But if Laos keeps losing its elephants to other countries such projects will simply not be possible. "The law against all forms of exportation of live elephants must be enforced more firmly if the Land of a Million Elephants wants to keep its population alive," said Duffillot.


[guardian.co.uk > Environment > BP oil spill]

BP oil spill: Endangered species still at risk
Deepwater Horizon spill in US leads to rise in dolphins and endangered brown pelicans injured or killed this week

Suzanne Goldenberg
guardian.co.uk, Monday 9 August 2010 20.39 BST
Article history

{Deepwater Horizon: US officials say the BP oil spill has resulted in a rise in the number of brown pelicans killed or injured in the past week. Photograph: Bevil Knapp/EPA}

US officials recorded a big jump in the numbers of dolphins and endangered brown pelican and sea turtle injured or killed by the BP spill over the past week, even as officials were proclaiming that the oil was rapidly disappearing from the Gulf.

Some 1,020 sea turtles were caught up in the spill, according to figures (pdf) today – an ominous number for an endangered species. Wildlife officials collected 177 sea turtles last week – more than in the first two months of the spill and a sizeable share of the 1,020 captured since the spill began more than three months ago. Some 517 of that total number were dead and 440 were covered in oil, according to figures maintained the Deepwater Horizon response team.

"It is a high number for any endangered species," said Elizabeth Wilson, a scientist for the Oceana conservation group. The number of dolphins, whales and other marine mammals captured or found dead also rose last week, from 69 to 76. An analysis by the National Wildlife Federation said the numbers of oiled birds collected had nearly doubled since the well was capped, from 37 to 71 a day.

It was not immediately clear why the numbers of injured and dead wildlife have jumped. Kevin Godsea, a fish and wildlife official overseeing the rescue of threatened brown pelican, said many of the more recent victims were hatchlings who took their first flights right into the oil. "We had a lot of young birds hanging right around the boomed areas of rookeries, and lot of those young birds are testing out their wings and they are getting right into the oil," he said.

Older pelicans exposed to oil are also able to survive much longer because of relatively warm temperatures in the Gulf, and are only succumbing now, he said.

In addition, he said officials had purposely stayed away from island bird sanctuaries to avoid exposing hatchlings to disease.

But that concern to avoid disturbing habitat may have put pelican eggs and hatchlings at greater risk once able-bodied pelican fled the oil.

"There has been a lot of criticism of fish and wildlife for the fact that they never actually went on the islands, and because they did not, abandoned nests were left so that any chicks that were already hatched died, and any eggs that were left were also left to die," said Cynthia Sarthou executive director of the Gulf Restoration Network.

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[Sci/Environment News] from [BBC NEWS]

[bbc.co.uk > News > Science & Environment]

Million dollar maths puzzle sparks row
A claim to have solved one of the most difficult riddles in mathematics has been challenged by scientists.

By Victoria Gill
Science reporter, BBC News
11 August 2010 Last updated at 14:40 GMT

{P vs NP has been described as the biggest unsolved problem in computer science}

Vinay Deolalikar, a mathematician based at Hewlett-Packard laboratories in California, US, claims to have solved the problem of P vs NP.

This has been described as the biggest problem in computer science; it is one of seven Millennium Prize Problems set out by the Clay Mathematics Institute.

But maths experts have weighed in to point out flaws in his proof.

Clay has offered one million US dollars in prize money for the solution of each of these problems, which they declared to be the most difficult in maths.

{“P vs NP is asking - can creativity be automated?”
Scott Aaronson
MIT}

Dr Deolalikar published his proof in a detailed manuscript, which is available on the HP website. His equations, he said demonstrated "the separation of P from NP".

If this is the case, Dr Deolalikar will be the first person to have proven that there is a difference between recognising the correct solution to a problem and actually generating the correct answer.

Scott Aaronson, a computer scientist at the Massachusetts Institute of Technology (MIT) in the US, explained to BBC News why this problem was so significant.

"People sometimes use the analogy of a jigsaw - it can be hard to complete the jigsaw, but if someone has done it, it's pretty easy to check - you just look at it," he said.

P vs NP poses the following question: If there is a problem that has this property - whereby you could recognise the correct answer when someone gives it to you - then is there some way to automatically find that correct answer?

"There's always one way a computer can find the answer- just by trying all the possible combinations one by one," said Dr Aaronson.

"But if you're trying to break a cryptographic code, for example, that could take an astronomical amount of time.

"P vs NP is asking - can creativity be automated?"

Dr Deolalikar claims that his proof shows that it cannot.

It may seem esoteric, but solving P vs NP could have "enormous applications", according to Dr Aaronson.

From cracking codes to airline scheduling - any computational problem where you could recognise the right answer, this would tell us if there were a way to automatically find that answer.

'Sanity test'

But Dr Aaronson says the new proof may fail a "very simple sanity check".

One way to test a mathematical proof, he said, is to ensure that it only proves things we know are true. "It had better not also prove something that we know to be false."

Other mathematicians have responded to Dr Deolikar's paper by asking him to show that his proof passes this test.

"Everyone agrees, said Dr Aaronson, "if he can't answer this, the proof is toast."


[bbc.co.uk > News > Science & Environment]

Ancient language mystery deepens
A linguistic mystery has arisen surrounding symbol-inscribed stones in Scotland that predate the formation of the country itself.

By Victoria Gill
Science reporter, BBC News
11 August 2010 Last updated at 00:05 GMT

{Many of the stones are believed to have been carved during the 6th Century}

The stones are believed to have been carved by members of an ancient people known as the Picts, who thrived in what is now Scotland from the 4th to the 9th Centuries.

These symbols, researchers say, are probably "words" rather than images.

But their conclusions have raised criticism from some linguists.

The research team, led by Professor Rob Lee from Exeter University in the UK, examined symbols on more than 200 carved stones.

They used a mathematical method to quantify patterns contained within the symbols, in an effort to find out if they conveyed meaning.

Professor Lee described the basis of this method.

"If I told you the first letter of a word in English was 'Q' and asked you to predict the next letter, you would probably say 'U' and you would probably be right," he explained.

"But if I told you the first letter was 'T' you would probably take many more guesses to get it right - that's a measure of uncertainty."

Using the symbols, or characters, from the stones, Prof Lee and his colleagues measured this feature of so-called "character to character uncertainty".

They concluded that the Pictish carvings were "symbolic markings that communicated information" - that these were words rather than pictures.

{“It's like finding a menu for a restaurant [written in English], and that being your sole repository of the English language”
Professor Rob Lee
Exeter University}

Prof Lee first published these conclusions in April of this year. But a recent article by French linguist Arnaud Fournet opened up the mystery once again.

Mr Fournet said that, by examining Pictish carvings as if they were "linear symbols", and by applying the rules of written language to them, the scientists could have produced biased results.

He told BBC News: "It looks like their method is transforming two-dimensional glyphs into a one-dimensional string of symbols.

"The carvings must have some kind of purpose - some kind of meanings, but... it's very difficult to determine if their conclusion is contained in the raw data or if it's an artefact of their method."

Mr Fournet also suggested that the researchers' methods should be tested and verified for other ancient symbols.

"The line between writing and drawing is not as clear cut as categorised in the paper," Mr Fournet wrote in his article. "On the whole the conclusion remains pending."

But Prof Lee says that his most recent analysis of the symbols, which has yet to be published, has reinforced his original conclusions.

He also stressed he did not claim that the carvings were a full and detailed record of the Pictish language.

"The symbols themselves are a very constrained vocabulary," he said. "But that doesn't mean that Pictish had such a constrained vocabulary."

He said the carvings might convey the same sort of meaning as a list, perhaps of significant names, which would explain the limited number of words used.

"It's like finding a menu for a restaurant [written in English], and that being your sole repository of the English language."

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[Sci/Environment News] from [BBC NEWS]

[bbc.co.uk > News > Science & Environment]

Former Senator Ted Stevens dies in Alaska plane crash
Former Alaska Senator Ted Stevens, 86, has died in a plane crash in Alaska while en route to a fishing trip.

11 August 2010 Last updated at 12:52 GMT

{Survivors of the crash were airlifted back to the Kulis Air National Guard Base in Anchorage}

Former Nasa chief Sean O'Keefe was also aboard the small plane with his teenage son but both survived.

Officials said five people had been killed and four had survived - with two badly hurt.

The wreckage is located on a mountainside near the town of Dillingham. Rescue and recovery efforts were slowed by bad weather.

Mr O'Keefe is in a critical condition and his son is being treated for serious injuries, an Alaskan hospital official said on Wednesday.

President Barack Obama paid tribute to Mr Stevens in a statement.

"A decorated World War II veteran, Senator Ted Stevens devoted his career to serving the people of Alaska and fighting for our men and women in uniform," he said.

"Michelle and I extend our condolences to the entire Stevens family and to the families of those who perished alongside Senator Stevens in this terrible accident."

{Alaska Governor Sean Parnell: "He (Ted Stevens) will be deeply missed here and beyond"}

Also killed was the pilot, Theron "Terry" Smith, 62, and a 16 year-old.

Mr O'Keefe and his teenage son suffered broken bones and other injuries, former NASA spokesman Glenn Mahone said.

The alarm was raised on Monday evening when the plane failed to land on schedule. Shortly afterwards, local residents spotted the wreckage on the side of a mountain about 17 miles north of Dillingham.

Harsh weather conditions hampered the rescue effort until early the next morning, and Alaska National Guard used helicopter hoists to rescue four survivors.

Several local Samaritans had reached the wreckage before rescuers could arrive and tended to the survivors, officials said. The survivors were flown to Anchorage.

A crash investigation team arrived in the afternoon from Washington DC.

A Federal Aviation Administration spokesman said the downed plane was a 1957 DeHavilland DHC-3T and was registered to Anchorage-based General Communications Incorporated (GCI).

Spokesman Mike Fergus said the plane had been headed to Agulowak Lodge on Lake Aleknagik from a site owned by GCI on Lake Nerka.

Mr Fergus said the plane had not been required to file a flight plan because it was flying by visual flight rules.

Mr Stevens and Mr O'Keefe often went fishing together, and the former Alaska senator was planning a fishing trip near Dillingham, friend William Canfield told the Associated Press news agency.

'Bridge to Nowhere'

{“Alaska and the nation he so loved have lost a great man”
Stevens family statement}

In a statement, Mr Stevens' family praised his dedication to Alaska, saying "his legacy is the 49th star on the American flag", a reference to Alaska's place as the 49th state in the US.

"Alaska and the nation he so loved have lost a great man," the family said.

"We have lost a tremendous husband and father and grandfather. He loved Alaska with all his heart."

Mr Stevens was the longest-serving Republican in the history of the Senate, having been appointed to the body in 1968 and won election two years later.

He was voted out of office in 2008 after being found guilty of seven felony charges of failing to disclose costly home renovations and gifts given by an oil services company. He was narrowly defeated by Democrat Mark Begich.

But in April 2009 a federal judge overturned the convictions and exonerated him, citing prosecutorial missteps.

During his tenure in the Senate, Mr Stevens was renowned for his ability to draw federal tax dollars back to Alaska.

One of his best-known projects - known as the "Bridge to Nowhere" - was the focus of criticism by US groups who queried the more than $400m (£252m) price tag for the bridge's construction, noting it was to serve only a tiny population on an isolated island.

Sean O'Keefe

> Became chief of aerospace company EADS North America in 2009
> Served as Nasa Administrator from 2001-2005
> Appointed Secretary of the Navy by President George HW Bush in 1992
> Previously served as chief financial officer for the US defence department

Mr Stevens was one of two survivors of a 1978 plane crash at Anchorage International Airport in Alaska that killed his wife, Ann, and several others.

Mr O'Keefe led Nasa from December 2001 to February 2005, having been nominated for the position by President George W Bush.

His tenure at the space agency was marked by major accomplishments, such as landing the two Mars Exploration Rovers on the surface of the Red Planet.

But he was also in charge during the Columbia space shuttle disaster, which resulted in the loss of seven astronauts. The panel investigating the incident made numerous recommendations to improve safety, but the accident hastened the demise of the shuttle as America's manned space vehicle.

The plane crash is the third in less than two weeks in the state.