Welcome, Guest. Please login or register.
Did you miss your activation email?
Sep 20, 2017, 01:41 AM
Pages: 1 2 [3] 4 5 ... 10
 21 
 on: Sep 19, 2017, 04:51 AM 
Started by Rad - Last post by Darja
Farmers in Sudan battle climate change and hunger as desert creeps closer

Haphazard rains and increasing desertification in the eastern state of Gedaref are destroying previously fertile soil and leaving villagers unable to farm

Hannah McNeish in Gedaref
Guardian
9/19/2017

In Sudan’s eastern state of Gedaref, nicknamed “the granary” for its vast rows of sesame, sorghum and millet, banks of sediment and gravel are popping up as high as hills around the farms – the result of deforestation and erratic rains causing watering holes to overflow.

Locals call them karab, meaning “something useless”, says environmental scientist Tarig El Gamri, standing atop one such mound. He points out the water mark swirls etched around one of many deep gullies near the village of Wad Hassan, a 45-minute drive east of Gedaref city.

“Climate change affected the intensity of rainfall. When it is very intense, you have very quick and very high runoffs, and this is what we are seeing now,” says El Gamri, a project coordinator at the Sudan Higher Council for Environment and Natural Resources. “They spoil the soil. Now you see they cannot cultivate such land, because it has lost the levelling.”

In 2015, Gedaref had 70ml of rain. This year, it has had 600ml so far. These extremes have led to flash floods and desertification, which is destroying arable land.

“Last year, the rain didn’t come and everything was destroyed,” says Aisha Youssef Ahmed in the neighbouring village of Siraj Alnour.

More intense droughts and failed rains have ruined harvests and also affected livestock: the cows that used to grow big and strong are skinny and often have to be sold off. Ahmed, 65, never thought that “rich, lush and productive” Gedaref would become a place “where everything has got worse”.

But while floods from overflowing wadis are washing away fertile topsoils or morphing farmland into unworkable shapes, the annual riverbank floods that people relied on to grow watermelons have declined due to heat, evaporation and dam construction in Sudan and across the border in Ethiopia.

“The river level has changed over the past 15 or 20 years,” says Wad Hassan’s chief, Ahmed Omar, standing on a rock next to the water where men paddle out in canoes to catch ever more scarce fish. “The water level used to be much higher.”

Omar, 60, has seven children, all of whom will become farmers in a state where most people farm and more than half the population lives below the poverty line.

Only a few children make the two-hour walk from Siraj Alnour – home to about 220 families – to a village that has a school. The scorching temperatures so exhaust and dizzy the children that they often have to be put to bed after school. Others are told to play only in the sparse patches of shade offered by thorn trees.

“Summer was always hot, but the winters are getting hotter. It used to be cooler, like 15C-20C” says Siraj Alnour’s chief, Idriss Mohammed Abdallah, who remembers the many trees of his boyhood in the 1970s. “Year after year they disappeared and the forest shrank as the village grew.”

It was then that the desert and gullies moved in.

“We had to shift here because the land was moving and pushed us back,” he says, standing in one of many gullies that threatens the new village.

“Now it depends on the trees, as the desert is moving towards us. People won’t be able to settle here. They won’t stay in the same place,” he says – even though “there is nowhere else to go” for farmers in one of Sudan’s most important breadbaskets.

Khalid Hashim Ibrahim, the state agricultural coordinator, says: “All of Sudan is affected by the low production in Gedaref, and also the production here is exported to other countries, especially neighbouring countries like Ethiopia and Eritrea and also the Gulf countries, like Saudi and the Emirates – for animals and food. This is very clear if you go to the north of the state. Some agricultural areas [have] now become sand soil.”

By way of example, Ibrahim points to Butana village’s population shrinking from 72,000 to about 12,000 seasonally, and the resulting conflicts over grazing lands or services in swelling cities.

The UN development programme has been running pilot climate change adaptation programmes in Butana, Wad Hassan and Sirag Elnour to try to stop good soils from shifting or drying up, and farmers waiting on rains and grains to survive.

Solar-powered water pumps have eased the reliance on rain-fed agriculture and allowed people to plant a greater range of crops. “Now, because of these extra irrigation methods, we can grow all vegetables,” says Omar.

Between the houses lie many community gardens full of tangled vines. Farmers proudly show off two varieties of cucumber and kiss some of the fruits of their newfound, year-round irrigation.

Small nurseries – comprising of a few rows of mud and wire mesh frames – are growing thousands of seedlings into trees, which are planted around homes and fields for protection against the elements. The introduction of butane gas has stopped people from using charcoal, while heavy fines are imposed on anyone who cuts down trees – which people now understand are their only defence.

Unless people really start working to save Gedaref’s soils, says Ibrahim, “the future is very dark”.

“The period between the 1970s to 2000 was very comfortable here in Gedaref, but now there are some big problems,” says Khalid Hisham Ibrahim, echoing the view of several farmers. “Low productivity, high temperatures and high fluctuation of rainfall … There is a consensus about this phenomena,” as well as about climate change-related health issues like increasing outbreaks of malaria.

Ibrahim, who farms to supplement his tiny government salary, has wondered whether he should leave one of Sudan’s only peaceful patches of green to find work in the capital, Khartoum, or – like thousands of others – cross the deserts and the seas for a new life.

“No, Khartoum not good – to Gulf countries, to other countries,” he says, before guffawing at his next thought. “Maybe migrate to America!”

 22 
 on: Sep 19, 2017, 04:46 AM 
Started by Rad - Last post by Darja
Put a price on urban trees – and halt this chainsaw massacre

Patrick Barkham

From chestnuts in south London to elms in Sheffield, they improve mental health, and stem pollution and floods. Yet policymakers fail to see them as assets

Guardian
19 September 2017 17.49 BST

It’s a grim season for urban trees. The usual bustle of bicycles beneath a grand parade of 140-year-old chestnut trees that crosses Tooting Common, in south London, will cease tomorrow. Wandsworth council is closing Chestnut Avenue, the chainsaws are readied, and more than 50 much-loved mature trees will soon be chopped down.

In Sheffield, despite vociferous opposition from local residents and high-profile people such as Jarvis Cocker to Michael Gove, the final tranche of thousands of mature street trees are being removed. This month in the city marks the beginning of the end for the Chelsea Road elm, a rare surviving English elm on which lives a colony of equally rare white-letter hairstreak butterflies.

The councils overseeing these chainsaw massacres are different politically. But they share a tragic inability to see street trees as an asset rather than a liability. They’re also ignominiously failing to use new tools at their disposal to calculate the real value of their trees.

In Wandsworth, a wealthy Conservative council is lavishing £45,000 of Heritage Lottery cash earmarked for rejuvenating Tooting Common on replacing the chestnuts with young lime trees. Its justification is health and safety after one tree suddenly fell down last winter. An independent expert report for the council suggested it might consider replacing the whole avenue.

When residents objected to substituting their grand old trees with a sleek avenue of cheap-to-maintain young trees, the council conducted a consultation: 9,000 letters went out, and most of the 700 respondents picked the rather skewed “choice” of a new avenue over occasionally tatty-looking old trees. More than 5,000 mostly local people have since signed a petition to save Chestnut Avenue.

Residents commissioned another expert report by an independent tree consultant. Jeremy Barrell is no tree-hugger and is routinely employed by councils to assess and remove trees. Barrell warns Wandsworth that planting an avenue of one species is a recipe for disaster in an era of fast-moving globalised tree diseases. We need a mix of trees. He concludes the most cost-effective option would be to retain the avenue, trim the older trees, remove a couple, and replant with other species. He’s so confident that the chestnuts can be made safe that he’s offered the council free coverage under his own professional insurance.

Barrell also performed a calculation developed by arboralists called Cavat. Just as a building surveyor can calculate the value of a house, so a tree officer can calculate the asset value of a tree – how much it costs to replace it. This reveals a useful truth: not all trees are equal, and big street trees are far more valuable than small trees.

Chestnut Avenue is currently worth £2.6m, according to this method. The young trees that will replace it are estimated at £50,000-£100,000. Spending £45,000 to destroy a multimillion-pound community asset doesn’t stack up. In Sheffield’s long-running tree saga, independent professionals calculated that trees worth £66m have been cut down in the past five years.

The ruination of this community asset is being orchestrated by a cash-strapped Labour council that sought salvation in a PFI contract with the infrastructure company Amey to rebuild its roads. Big trees are replaced by saplings, which are cheaper to maintain over 25 years of the contract but possess few of large trees’ beneficial effects – for example on flood alleviation and pollution. The devil is in the opaque interpretation of the much-redacted PFI contract. This contract only permits a fairly limited range of engineering solutions for unruly trees, but campaigners have calculated that nearly 50% of the trees earmarked for destruction could be saved using solutions listed in the contract at no extra cost to the council.

    Spending £45,000 to destroy a multimillion-pound community asset doesn’t stack up

The puzzle in Sheffield has long been why the council has not used its power to save special trees, such as the Chelsea Road elm. But residents believe they finally got their answer when councillors revealed that if they “saved” any tree they – and not Amey – would then become liable for subsequent maintenance. When the council signed this disastrous PFI contract, it put a gun to its own head. Sheffield’s trees have been privatised for 25 years. And the contract firmly enshrines them as liabilities.

It needn’t be like this. Future contracts could include a recognition of street tree values using Cavat, or more sophisticated American software called i-Tree. The latter calculates the annual value of each street tree in terms of certain ecosystem services: flood alleviation, cooling, pollutant removal and carbon sequestration. According to i-Tree, London’s trees provide £133m of benefits each year.

Some environmentalists view such “ecosystem service” arguments as the great hope for saving a planet ruled by accountants. Others fear that such calculations are reductive, and underestimate “natural assets” – i-Tree valuations do not include less easily calculable tree benefits, such as the improved mental health of local people, or ecological diversity. Ultimately, nature will always be the loser in any cost-benefit crunch.

Nevertheless, giving trees a price looks like a good, pragmatic way to retain them in urban environments. What the streets of Wandsworth and Sheffield show us is that policymakers cannot be relied upon to recognise these precious assets. The only solution is for local communities to teach them.

• Patrick Barkham is a natural history writer for the Guardian

***************

UK cities expected to get millions of pounds for green energy projects

Ministers are thought to be planning to offer £3m for initiatives such as solar panels on social housing
Solar panels on a roof

Adam Vaughan
Guardian
9/19/2017

Green energy projects run by cities and local authorities around the UK stand to receive millions of pounds of government support, providing another fillip for renewable power just a day after the subsidised price of windfarms hit a record low.

The Guardian understands that ministers this autumn will offer more than £3m to help local leaders build low carbon initiatives, such as installing solar panels on social housing.

The funding would be a key plank of the government’s upcoming blueprint on how to meet the UK’s binding carbon targets, the Clean Growth Plan.

The anticipated support is a response to calls from a network of more than 70 UK cities, which said they wanted to build clean energy projects at a local level but warned that they were struggling to finance them.

“We believe the UK has a great opportunity to lead the world in an early shift to a fossil-fuel-free economy, just as we have led the world in previous industrial transitions,” said Judith Blake, leader of Leeds city council, and John Holdich, leader of Peterborough city council.

Both cities are members of the UK100, which backs action on climate change and clean energy.

But in a new report, the network said local authorites often lacked the technical expertise for accessing finance and EU funds being cut off post-Brexit posed a further challenge.

The report’s authors, former employees of the engineering giant Arup and the recently privatised Green Investment Bank, called on ministers to tackle the problem by creating Clean Energy Action Partnerships between national and local government.

The partnerships would employ teams of experts to support councils who want to build local low carbon projects, such as heat networks or solar power.

Claire Perry, the climate minister, is understood to be sympathetic to the proposals. One idea put forward in the UK100’s report is that clean energy projects run by councils could enjoy a cut in business rates.

Perry is believed to have told local leaders she looks forward to helping them access finance.

Perry said: “We want to build on our success and that’s why collaboration across government, and with people and organisations throughout the country, is vital as we prepare to launch our Clean Growth Strategy.”

The backing for locally owned clean energy came as a thinktank of Labour members and MPs criticised the lack of UK ownership for offshore windfarms, such as the ones awarded nearly £200m a year in subsidies on Monday.

The Labour Energy Forum found the Danish state-owned company Dong Energy owned 31.5% of all offshore wind capacity in the UK, with private German, Spanish and Swedish firms dominating the rest of the market.

Rebecca Long-Bailey, the shadow business secretary, said Labour supported offshore wind but wanted to see windfarms built off the coast that were publicly owned by the UK.

“Labour not only supports investment and real proactive support for the renewables sector but we also commit to ensuring more rapid growth and diversification of ownership within this important sector through the creation of publicly owned and locally accountable energy companies and co-operatives,” she said.

 23 
 on: Sep 19, 2017, 04:44 AM 
Started by Rad - Last post by Darja
In Darwin’s Footsteps

By JONATHAN WEINER
NY Times
9/19/2017

Charles Darwin spent only five weeks on the Galápagos Islands, and at first, the British biologists Peter and Rosemary Grant didn’t plan to stay very long either — a few years at most.

They landed in 1973 on the tiny uninhabited island of Daphne Major, the cinder cone of an extinct volcano. (Darwin himself never set foot there.) Daphne is as steep as a roof, with cliffs running all around the base, and just one small spot on the outer slope flat enough to pitch a tent.

Their goal, as they relate in their new book, “40 Years of Evolution,” was to study finches in the genus Geospiza — the birds that gave Darwin some of his first inklings of evolution by natural selection — and to try to reconstruct part of their evolutionary history. Instead, they made an amazing discovery.

After several years of meticulous measurements, the Grants and their students realized that the finches’ dimensions were changing before their eyes. Their beaks and bodies were evolving and adapting from year to year, sometimes slowly, sometimes strikingly, generation after generation. The researchers were watching evolution in real time, evolution in the flesh.

Darwin never dreamed that was possible. In the first chapter of “On the Origin of Species,” he writes that while natural selection is at work everywhere and always, “we see nothing of these slow changes in progress, until the hand of time has marked the lapse of ages.”
Continue reading the main story

The Grants discovered that Darwin’s process was more powerful than he thought. So they stayed on, and on. Daphne Major turned out to be a perfect theater for watching evolution in action — big enough to support many hundreds of finches, but small enough that the Grants and their students and assistants could band and recognize and measure almost every bird.

In researching my own book, “The Beak of the Finch,” I came to know the Grants well. When I first met them, more than two decades ago, they were in their 50s, cheerfully focused, understated, competent. They were also very fit, to use Darwin’s word. They had to be, to carry all their food and water up the cliff of the desert island.

They kept up their watch during years of downpours and years of drought — seasons of feast and famine for the finches. And Darwin’s process unfolded before their eyes in intense episodes that illustrated better than anything in the Origin the struggle for existence, and the ways that life adapts and emerges fitter from the struggle.

When I read “40 Years of Evolution,” I started near the end. I wanted to know more about the Grants’ latest discovery, which I wish I could have witnessed in person.

Its own origins date to 1981, when a strange finch landed on the island. He was a hybrid of the medium-beaked ground finch and the cactus finch. He had the sort of proportions that touch our protective feelings: a big head on a stout body. In other words, he was cute. They called him Big Bird.

Hybrids are not unknown among Darwin’s 13 species of finches, but they are rare. Because they evolved so recently, birds of these different species can mate but ordinarily choose not to. (Our own ancestors seem to have felt the same way about Neanderthals.)

Big Bird had a strange song that none of the finch watchers had ever heard. His feathers were a rich, extra-glossy black. He had more tricks in his repertory than his neighbors: He could crack the spiky, troublesome seeds of the Tribulus plant, normally the specialty of the big-beaked ground finch, as well as small seeds favored by the small-beaked ground finch. He could dine on the nectar, pollen and seeds of the cactus, which belongs to the cactus finch.

Big Bird mated with a medium-beak on Daphne. Their offspring sang the new song of Big Bird. And slowly, Big Bird became a patriarch. He lived 13 years, a long time for one of Darwin’s finches. His children, grandchildren and great-grandchildren all sang his song, and they were clannish. They roosted in hearing distance of one another on the slopes of Daphne Major. What’s more, they bred only among their kind, generation after generation.

Big Bird’s lineage has now lasted for 30 years and seven generations. The Grants are cautious about its prospects — “It is highly unlikely that we have witnessed the origin of a long-lasting species, but not impossible,” they write — but other scientists are buzzing.

Comet Siding Spring closes in on Mars; Galapagos scientists watch Darwin’s finches evolve in real time; the tegu, an invasive lizard species, has found a comfortable home in the Sunshine State.

“I think it’s fantastic, the most exciting research finding I’ve read in the last decade,” said Jonathan B. Losos, an evolutionary biologist at Harvard.

The Grants say that if the Big Birds are, in fact, a species, they would call them Geospiza strenuirostris, from the Latin word meaning strong, exceptionally vigorous and active.

But alas, there are rough times ahead in the Galápagos, as in every other place affected by global warming. In the coming decades, as the climate of these islands grows warmer and wetter, Daphne may lose its cactus. And Big Bird can’t live without cactus.

Even in 40 years, of course, you can’t expect to witness the whole story of evolution, which has been going on for nearly four billion. Still, it turns out that if you know what to look for, put yourself in the right place and keep your eyes open, you can see a lot. The Grants have won just about every award in their field, including the prestigious 2009 Kyoto Prize in Basic Science. (The Nobel Prizes don’t have a category for evolution.)

“The Grants’ work is possibly the most important research program in evolutionary biology in the last half-century,” Dr. Losos told me in an email. “It has reshaped both how we understand evolution and how we study it. Before their work, no one was trying to study evolution in action — now it seems that everyone is.”

And life on Daphne was kind to the Grants. They never seemed to age, although Peter’s beard grew almost as long and white as the celebrated beard of Darwin, whom he resembles somewhat. When they weren’t camped on Daphne, they analyzed their data at Princeton in adjoining offices with the door open between them. They write books and papers together, give lectures together, finish each other’s sentences.

There’s an old proverb, “Just sink one well deep enough.” For the Grants, Daphne Major has been a magic well. With their four decades of work on the island, they’ve made it a magnificent microcosm, a model of life on Earth. And with their long collaboration on Daphne and at Princeton (where they’re now emeritus professors), they make a model for how to live a happy life.

A few nights ago, I called the Grants at home in Princeton to talk about Big Bird. They sounded the same as ever, still fascinated by the finches and still finishing each other’s sentences. I asked when the significance of the story had dawned on them.

“Maybe in 2007, we really grasped what was going on,” Peter said.

“But it was a very gradual process,” Rosemary added. “No eureka moment.”

If they hadn’t stayed on, hadn’t kept watching all those years, they would never have witnessed this surprise ending. “But then,” Rosemary said, “you could almost say that anything we would see on Daphne, we didn’t expect.”

Rosemary does most of the talking on the phone these days; Peter had warned me in an email, “I am acoustically challenged.” He recently had a hip replacement, from which he is recovering nicely. They’re both 77. They can’t keep going back to Daphne year after year.

“But we’d like to monitor and see how our Big Birds are doing,” Rosemary said with a small laugh.

At the end of the last chapter of “40 Years of Evolution,” there’s a page with two photographs. One shows the Grants at work in the island’s only cave, where they did their cooking and stored their supplies. “A cave for cool reflection,” the caption says.

Under that is a little photograph of two brown boots, battle-scarred from all that hiking up and down on lava.

“Boots,” the caption says. “Finis.”

 24 
 on: Sep 19, 2017, 04:41 AM 
Started by Rad - Last post by Darja
Huge increase in badger culling will see up to 33,500 animals shot

Ministers say culls are vital for cutting TB infections in cattle but scientists say there is little evidence to support the policy

Damian Carrington Environment editor
Guardian
9/19/2017

Up to 33,500 badgers will be shot this autumn in an attempt to control tuberculosis in cattle, a huge rise from the 10,000 killed in 2016.

The government has announced that 11 new badger cull areas have been licensed, adding to the 10 already in place. Devon now has six badger culls under way, with Somerset and Wiltshire having three each, with others in Cheshire, Cornwall, Dorset, Gloucestershire and Herefordshire.

The badger culls are highly controversial, with ministers and some farmers arguing they are a vital part of curbing bovine tuberculosis (bTB), which led to 29,000 cattle being slaughtered in 2016 at a cost of £100m. However, scientists say there is little evidence that the current culls will help cut bTB rates, and could spread the disease even further by disrupting badger populations.

Ministers also announced the resumption of a badger vaccination scheme in “edge” areas between high and low TB regions. The scheme, suspended for the last two years due to a shortage of vaccine, will fund 50% of the costs of successful applicants. Restrictions on the movement of some high risk cattle are also being put in place – some scientists say this is the key to ending the epidemic.

“Bovine TB not only has a devastating impact on our beef and dairy farms, but causes harm and distress to infected cattle,” said the farming minister George Eustice. “We have a clear plan to eradicate the disease over the next 20 years. Vaccination is just one part of our comprehensive strategy, which also includes tighter cattle controls, improved biosecurity and badger control in areas where bTB is rife to tackle the reservoir of disease in wildlife.”

Each badger cull is set a minimum and maximum number of badgers to be shot. This is to ensure the animals are not wiped out locally, while killing enough for the cull to be effective – although scientists have previously criticised the government-set targets as “rubbish” and “ridiculously easy”.

The total number of badgers to be killed across all the areas this autumn has been set at a maximum of 33,347 and a minimum of 21,797. The largest cull is one in Dorset that could see more than 7,000 badgers killed. The culls all met their targets in 2016, though earlier culls did not and were not effective or humane, according to an independent expert group that was subsequently disbanded by ministers.

Minette Batters, deputy president of the National Farmers Union, said: “The NFU has always supported a comprehensive and proportionate eradication strategy, which balances disease controls measures with business sustainability. We must have every option available to us to tackle TB.” She also welcomed a new TB advisory service for farmers in risky areas.

However, Prof Rosie Woodroffe, at the Zoological Society of London and who conducted a landmark 10-year trial on badger culling, said: “It’s depressing that the government is pursuing badger culling over such huge areas when the benefits remain so uncertain. Data published today suggest that, after three years of culling, cattle TB in the first cull zones was still no lower than that in unculled areas.”

Steve Trotter, at the Wildlife Trusts, said: “We work closely with many farmers, day in, day out, and we recognise the pain and hardship of those whose cattle herds have been devastated by bTB, but killing badgers will not solve the problem. The primary route of infection is cattle-to-cattle contact. The government’s badger cull is flying in the face of science.” He said vaccination costs £82 per badger, compared to £6,800 per culled animal.

Peter Martin, chairman of the Badger Trust, said: “Shooting badgers has been condemned as ‘inhumane’ by both the government’s own independent experts and the British Veterinary Association. “But it it’s also a disaster for cattle, Britain’s farmers and the taxpayer.”

Martin said a more accurate but more expensive TB test should be used to help control the spread of the disease: “The £40m wasted on culling badgers could be used to pay for this right now.” He added: “The government has no idea even how many badgers there are, let alone whether or not they are infected with TB. They also have no clear or effective method for monitoring whether the policy is working.”

Claire Bass, executive director of the Humane Society International UK, said: “It appears the government is now dispensing with the pretence of science towards a culling free for all, without monitoring or evaluation.”

Woodroffe said in February that the government was misusing data: “When evidence is being cherry-picked and presented in the best possible light, it ceases to be evidence. It is fake science.”

 25 
 on: Sep 19, 2017, 04:38 AM 
Started by Rad - Last post by Darja
The Strange Tale of a New Species of Lizard

Carl Zimmer
NY Times
9/19/2017

Each year, scientists publish roughly 17,000 detailed descriptions of newly discovered animals. Recently, in the journal Breviora, researchers described yet another, a new species of lizard called Aspidoscelis neavesi.

At first glance, this seems to be a run-of-the mill lizard: a small, slender creature with spots along its back and a bluish tail. In fact, Aspidoscelis neavesi is quite exceptional. The lizard was produced in the laboratory by mating two other species, and its creation defies conventional ideas about how new species evolve.

The evolution of a new animal species is usually a drawn-out affair. Typically, an existing animal population is somehow divided, and the newly isolated populations reproduce only among themselves. Over thousands of generations, the animals may become genetically distinct and can no longer interbreed.

Of course, scientists have long known that some related species sometimes interbreed. But the hybrid progeny generally were thought to be evolutionary dead-ends — sterile mules, for instance. In recent decades, however, researchers have learned that these hybrids may represent new species.

Some of the most striking examples occur among whiptail lizards, which live in the southwestern United States. In the 1960s, scientists noticed that some whiptail lizard species had a strange genetic makeup. They have two copies of each chromosome, just as we do, but each copy is very different from its counterpart. The genes look as if they come from different species.

Perhaps stranger, many species produce no males. The eggs of the females hatch healthy female clones, a process known as parthenogenesis.

Normally, unfertilized animal eggs have only one set of chromosomes. The second set is derived from a male’s sperm following fertilization. But parthenogenic female whiptail lizards can duplicate the chromosomes in their offspring without males.

These findings led scientists to a hypothesis for how these strange species came about: Sometimes individuals from two different species of whiptail lizards interbreed, and their hybrid offspring carry two different sets of chromosomes.

Somehow, this triggers a switch to parthenogenesis. The female hybrids start to produce clones distinct from either parental species. In other words, they instantly become a new species of their own.

But it gets even more bizarre. Some species of whiptail lizards carry three sets of genes, rather than two.

How can that be? Scientists hypothesized that male lizards from sexually reproducing species sometimes mated with parthenogenic females. Sometimes, their sperm succeeded in fertilizing a female’s eggs, which already contained two sets of chromosomes. The egg now had three sets, and voilà: yet another a new species.

The strangeness doesn’t end there. In 1967, a Harvard graduate student named William B. Neaves was searching for whiptails around Alamogordo, N.M., when he found one with four sets of chromosomes.

Dr. Neaves concluded that the lizard was a hybrid. Three sets of chromosomes appeared to have come from a species called Aspidoscelis exsanguis. The fourth set hailed from a species called Aspidoscelis inornata. Both species live around Alamogordo.

Dr. Neaves didn’t follow up on this finding, instead pursuing a career researching fertility and stem cells. But at a dinner in 2002, he mentioned the whiptail lizards to Peter Baumann, a molecular biologist at Stowers Institute for Medical Research, where Dr. Neaves served as president.

Dr. Baumann decided it was high time to use new scientific tools to study whiptail lizards, and he and Dr. Neaves started making road trips to New Mexico to catch them and take them back to Stowers. As they came to understand the biology of the lizards better, they and their colleagues began to bring different species together to see if they could hybridize. Most of the time, their experiments failed.

In 2008, the scientists tried to recreate the hybrid with four sets of chromosomes. They put female Aspidoscelis exsanguis (the parthenogenic species with three sets of chromosomes) and male Aspidoscelis inornata in the same containers. In short order, the lizards started mating, and the females laid eggs. When the eggs hatched, the scientists examined the genes of the baby lizards and found four sets of chromosomes.

Four of the new hybrids were females. To the delight of the scientists, the females could clone themselves — and the offspring could produce clones of their own. Today, the scientists have a colony of 200 of these lizards.

Eventually the scientists became convinced they had produced a new species. They ran the idea past Charles J. Cole, a herpetologist at the American Museum of Natural History, who has studied whiptail lizards since the 1960s.

“As soon as they told me what they had done, I knew it was a species,” Dr. Cole said. The lizard’s body was clearly distinct from its parental species, and the fact that the species emerged in a lab seems irrelevant to Dr. Cole.

“It’s not a Frankenstein genome manipulation,” he said. “It’s lizards in cages doing their thing.”

Dr. Cole agreed to help Dr. Baumann and his colleagues formally describe the new species. Dr. Cole carefully cataloged the many features, both striking and subtle, that set the new lizard apart from other known whiptail species. They named it Aspidoscelis neavesi to honor Dr. Neaves.

“These lizards should have their own species,” said Laurence M. Hardy, a biologist at Louisiana State University Shreveport, who was not involved in the study. He said that they fulfilled the formal requirements.

But David Hillis, an evolutionary biologist at the University of Texas, questioned whether any lineage of hybrid whiptail lizards should be considered true species. “It is widely practiced, but often questioned,” he said.

Traditionally, scientists have looked at how animals reproduce to decide if they truly represent a species or just a subspecies. Animals within a real species produce offspring mostly with one another. As a result, their genes mix together into a single gene pool.

Are these new lab lizards really a species? Aspidoscelis neavesi doesn’t need to mate at all. It doesn’t maintain a single gene pool. The mutations that one lizard acquires will be passed down only to her offspring, not to others.

Aspidoscelis neavesi also raises a special puzzle, Dr. Hillis noted, because it emerged over and over again. Dr. Baumann and his colleagues have now successfully produced fertile hybrids of Aspidoscelis inornata and Aspidoscelis exsanguis dozens of times from different parents. Since each lineage comes from different parents, they could arguably be considered separate species, not just a new one.

Dr. Hillis says he thinks biology needs a different way to describe these lizards. “I think they are better termed ‘hybrid clones,’ ” he said. “That would represent a more accurate reflection of their relationship to the tree of life.”

Dr. Baumann argues that giving the lizards a species name is important simply to help scientists communicate. “It allows them to know what they’re talking about,” he said.

He and his colleagues have a lot to talk about. They are investigating how Aspidoscelis neavesi copes with having four sets of chromosomes. In humans, extra chromosomes can cause dramatic changes. An extra copy of chromosome 21, for example, leads to Down syndrome.

Yet Aspidoscelis neavesi appears to be a perfectly healthy, normal group of lizards. “If anything, we see a slight advantage,” Dr. Baumann said.

The good health of Aspidoscelis neavesi raises yet another puzzling question: If the parental species of Aspidoscelis neavesi live near one another, shouldn’t Aspidoscelis neavesi exist in the wild, too?

It’s possible that healthy hybrids do emerge from time to time, but that they have been the victims of bad luck. “If you’re rare, you’re more likely to go extinct by chance,” said James Mallet, a Harvard biologist who was not involved in the study.

On the other hand, it may be that Aspidoscelis neavesi is thriving unseen around Alamogordo. Dr. Cole hopes that the new paper, with its detailed description of the new species’ appearance, will help people to identify them.

“They may be out there somewhere, and we just don’t know it yet,” said Dr. Cole.

 26 
 on: Sep 19, 2017, 04:36 AM 
Started by Rad - Last post by Darja
From Fearsome Predator to Man’s Best Friend

Carl Zimmer
NY Times
9/19/2017   

Imagine a wolf catching a Frisbee a dozen times in a row, or leading police officers to a stash of cocaine, or just sleeping peacefully next to you on your couch. It’s a stretch, to say the least. Dogs may have evolved from wolves, but the minds of the two canines are profoundly different.

Dog brains, as I wrote last month in The New York Times, have become exquisitely tuned to our own. Scientists are now zeroing in on some of the genes that were crucial to the rewiring of dog brains.

Their results are fascinating, and not only because they can help us understand how dogs turned into man’s best friend. They may also teach us something about the evolution of our own brains: Some of the genes that evolved in dogs are the same ones that evolved in us.

To trace the change in dog brains, scientists have first had to work out how dog breeds are related to one another, and how they’re all related to wolves. Ya-Ping Zhang, a geneticist at the Chinese Academy of Sciences, has led an international network of scientists who have compared pieces of DNA from different canines. They’ve come to the conclusion that wolves started their transformation into dogs in East Asia.

Those early dogs then spread to other parts of the world. Many of the breeds we’re most familiar with, like German shepherds and golden retrievers, emerged only in the past few centuries.   

Meanwhile, back in China, those early dogs lingered on for thousands of years. Today, they’re known as Chinese native dogs. “The Chinese native dogs live in rural villages, helping humans to guard homes,” Dr. Zhang explained in an e-mail.

Dr. Zhang and his colleagues see Chinese native dogs as the key to better understanding how dogs evolved. Recently, they sequenced the entire genome of Chinese native dogs and compared them with the genomes of Asian wolves and modern breeds like German shepherds. By comparing the mutations in the genomes, they’ve been able to estimate when wolves and dogs diverged.

As they reported on Tuesday in the journal Nature Communications, they found that the split started 32,000 years ago. Those early dogs would have encountered small bands of hunter-gatherers. People didn’t settle in villages to farm in East Asia until about 10,000 years ago.

After dogs split from wolves, their genes began to evolve in a new direction. Dr. Zhang and his colleagues were able to identify some of these evolving genes. A number of them, it turned out, are active in dog brains. (Dr. Zhang and some of his colleagues published some of these results last week in the journal Molecular Biology and Evolution.)

Brian Hare, an associate professor at Duke University, has created a new method to research dog behavior, using the Internet and citizen science. By Jeffery DelViscio, Pedro Rafael Rosado, Robin Lindsay, Abe Sater and Kriston Lewis on Publish Date April 23, 2013. . Watch in Times Video: https://www.nytimes.com/video/science/100000002186890/decoding-dog-behavior.html?action=click&contentCollection=science&module=embedded&region=caption&pgtype=article
   
Some of the genes that evolved early in dog evolution are involved in smell or hearing. Others are active in a region called the prefrontal cortex, where mammals make decisions about how to behave. Some genes are involved in growing connections between neurons. One gene, called SLC6A4, transports a neurotransmitter called serotonin into neurons.

The results offer some tantalizing hints about how wolves first turned doglike. “The conventional view is that the hunter-gatherers go out and get a puppy,” said Chung-I Wu of the University of Chicago, an author of the Nature Communications study. If humans actually did breed early dogs this way, then dogs would have descended from a very small population.

That’s not what Dr. Wu and his colleagues have found, though. Instead, it appears that a large population of wolves started lingering around humans — perhaps scavenging the carcasses that hunters left behind.

In this situation, aggressive wolves would have fared badly, because humans would kill them off. Mellower wolves, by contrast, would thrive. If this notion turns out to be true, it means that we didn’t domesticate wolves — they domesticated themselves. SLC6A4 may have played a crucial part in this change, because serotonin influences aggression.

To test these ideas, Dr. Zhang and his colleagues are gathering DNA from more dogs and wolves. They also hope to collaborate with cognitive scientists to see how variants of genes like SLC6A4 affect the behavior of dogs today. Their results may also help explain human evolution, because Dr. Zhang and his colleagues found that some of the same genes that evolved in dog brains, such as SLC6A4, also experienced natural selection in human brains.

“Humans have had to tame themselves,” said Adam Boyko of Cornell University, one of Dr. Zhang’s collaborators on the Molecular Biology and Evolution study. “The process is probably similar to dogs — you have to tolerate the presence of others.”

 27 
 on: Sep 19, 2017, 04:32 AM 
Started by Rad - Last post by Darja

New Agreement Offers Brighter Future for Pacific Bluefin Tuna

By Amanda Nickson
Ecowatch
9/19/2017

The Pacific bluefin tuna is among the most depleted species on the planet, having been fished down more than 97 percent from its historic, unfished size. For years, this prized fish has been in dire need of strong policies that would reverse that decline, but the two organizations responsible for its management—the Western and Central Pacific Fisheries Commission (WCPFC) and the Inter-American Tropical Tuna Commission (IATTC)—failed in their recent efforts, allowing overfishing to continue and further risking the future of the species.

Last week, however, at a joint meeting of the WCPFC Northern Committee and IATTC, Pacific bluefin received a much-needed respite when its primary fishing nations—Japan, South Korea, Taiwan, Mexico and the U.S.—reached agreement with other member states on a long-term plan that would rebuild the population from its current status of 2.6 percent of pre-fishing levels to 20 percent by 2034. This agreement, if properly implemented, would start the species—and the fishing industry that depends on it—on a path toward sustainability.

After decades of inaction, why did these two fisheries management bodies agree to take the needed steps toward rebuilding? Because ignoring the problem became impossible for managers. In the past two years, three nations exceeded their catch limits. Amid increasing calls from The Pew Charitable Trusts and others for a complete fishing moratorium, and in a worst-case scenario, an international trade ban, the government representatives to the WCPFC committee and IATTC finally stepped up to make a change.

Perhaps most significant was the course reversal by Japan. By far the largest fishing nation for, and consumer of, Pacific bluefin, Japan had long resisted proposed rebuilding plans. This year, though, thanks in part to strong international pressure and growing media attention within the country on the plight of the species, the Japanese delegates dropped that opposition and helped make progress that just a few years ago seemed far out of reach.

Despite this commitment, the work to help Pacific bluefin recover has only begun. In the fishing season that ended on June 30, Japanese fishermen exceeded their catch limits by 334 metric tons, and with many reports of illegal fishing in Japan's waters, the real amount could be higher. The U.S., South Korea and Mexico also exceeded limits over the past two years. Rebuilding the species under the new quotas and timeline will be nearly impossible if such overages continue. All countries that fish for Pacific bluefin must pledge to strengthen their domestic controls and monitoring programs to guarantee that the commitments to rebuilding made this year are not squandered in the future.

The decision on Pacific bluefin made at the joint meeting could signal a move toward a greater focus on conservation at regional fisheries management organizations like the WCPFC and IATTC. This action by major fishing nations indicates that concrete action is possible. Fishermen and fleets now hold the key to a sustained recovery, and all countries must work together to uphold the new rules. If they can do that, real change on the water may come sooner than many of us expected.

 28 
 on: Sep 19, 2017, 04:31 AM 
Started by Rad - Last post by Darja

Buzz Kill: Climate Change Threatens Coffee-Pollinating Bees

By Marlene Cimons
Ecowatch
9/19/2017

The best coffee grows in the mountains, where it is cool. It needs low temperatures to thrive, which is why growers often put shade trees in their fields. But the mountains are getting hotter. And the higher you go, the less room there is to grow coffee. This is one reason scientists predict coffee will suffer in a changing climate.

New research suggests the fate of coffee may be worse than previously thought. Earlier projections underestimated the effects of climate change, specifically in Latin America, and failed to consider the consequences for coffee-pollinating bees, according to the study, which appears in the Proceedings of the National Academy of Sciences.

This is bad news, and not just for coffee lovers. It portends economic disaster for vulnerable farmers whose incomes depend on coffee. Most coffee growers in Latin America are small farmers whose food security relies on cash earned by selling coffee. In countries like Guatemala and Mexico, coffee is an important source of income for indigenous communities.

A coffee farmer picks fresh coffee cherries in Colombia.Neil Palmer / International Center for Tropical Agriculture

"Climate change threatens the primary livelihoods of millions of people in vulnerable communities around the world," said Taylor Ricketts, director of the Gund Institute for Environment at the University of Vermont, and coauthor of the study. "In all, probably 100 million people are involved in its production, most of them rural and poor. So there is more at stake here than the price of a nice espresso in New York or Paris."

The study, conducted with advanced computer modeling, spatial analysis and field data, predicts that climate change could reduce coffee-growing areas in Latin America—the world's largest coffee-producing region—by as much as 88 percent by 2050, with the largest declines in Nicaragua, Honduras and Venezuela.

The models also suggest that climate change will drive out multiple species of bees in some places. About 80 percent of growing areas "currently have at least ten [species of bee], and that drops almost in half in our future scenarios," Ricketts said. Though, he noted that just five species are "likely to be sufficient." This is the first study to examine the combined effects of both climate and pollination and how they will change under global warming "in ways that will hit coffee producers hard," Ricketts said.

Global warming could shrink coffee-growing areas in Latin America by as much as 88 percent by 2050.Neil Palmer / International Center for Tropical Agriculture

Coffee production depends on pollination, "so the question is whether we can still count on bees' contribution," said Pablo Imbach, an agronomist with the International Center for Tropical Agriculture in Hanoi, and the paper's lead author. "Productivity increases with the number of bee species." Moreover, bees can offset some of the harmful effects of climate change by boosting coffee productivity, scientists said.

"It's a David and Goliath situation," Imbach said. "There is the enormously powerful force of climate change that the world is trying to rein in, but bees—these comparatively tiny creatures—can, in some areas, actually play an important role in limiting the impact of climate change on coffee farms."

The findings were not all bad. The scientists projected a slight increase in coffee-growing suitability in Mexico, Guatemala, Colombia and Costa Rica, mainly in mountainous areas where the temperatures are expected to stay cool enough to support both coffee growth and hearty bee populations.

The study emphasized the importance of preserving tropical forests, which are habitats for bees and other pollinators. Many coffee-growing areas are located within a mile of tropical forests, researchers said.

The projected change in the number of bee species across Latin America by 2050. Proceedings of the National Academy of Sciences

"Bees are vital to the integrity of coffee plots," Imbach said. "Without the services they provide, coffee yields will drop, and this will directly affect the incomes of the smallholder farmers. If there are bees in the coffee plots, they are very efficient and very good at pollinating, so productivity increases and also berry weight."

To improve coffee growth and bee pollination, the researchers recommended expanding bee habitats near coffee farms. Also, they urged that tropical forests be protected, and suggested more shade trees, weed strips and native plants that provide food and nesting for bees and other pollinators.

"Wild bees are a precious natural resource we should celebrate and protect," Ricketts said. "If managed with care, they can help us continue to produce billions of dollars in agricultural income and a diversity of nutritious food." Rickets stressed the importance of protecting pollinators from climate change. The consequences of not doing so could prove disastrous.

"Two-thirds of the most valuable commodities on earth rely on bees and other pollinators to produce well," Ricketts said. "That's easily worth tens of billions per year, every year. These crops also contribute essential nutrients to diets around the world. Ongoing declines in pollinators puts all this at risk. Pollinators are the essential and silent heroes of our global food system."

Reposted with permission from our media associate Nexus Media.

 29 
 on: Sep 19, 2017, 04:26 AM 
Started by Rad - Last post by Darja
Back to Saturn? Five Missions Proposed to Follow Cassini

By KENNETH CHANG
SEPT. 19, 2017
NY Times

For 13 years, NASA’s Cassini spacecraft sent back captivating observations of Saturn, and its rings and moons, solving some mysteries but raising plenty of new questions. With the spacecraft’s demise on Friday, the stream of data from Saturn has dried up.

“Until we go back, that’s a very distant world now,” Linda Spilker, the project scientist for Cassini, said during a news conference on Friday. “The details of the rings, and those small moons snuggled in so close — those are all gone until we go back.”

NASA currently has no plans to return to Saturn, but that could change. In the latest round in a scientific competition called New Frontiers, NASA specified categories of missions it would consider. Those include a probe to study Saturn’s atmosphere or a mission to go to Titan or Enceladus, two moons known to have oceans.

The New Frontiers program solicits ideas for missions from teams of scientists and engineers. These projects can be ambitious, costing up to about $1 billion. Earlier proposals included Juno, now orbiting Jupiter, and Osiris-Rex, currently en route to the asteroid Bennu.

NASA may announce finalists by the end of the year. A winning mission is to be selected by summer 2019 for launch around 2025. At least five submitted proposals take aim at Saturn, Titan or Enceladus.

Titan

As a spacecraft, Dragonfly would be an oddity: It would have propellers, like a helicopter — “a nuclear quadcopter to look for life on Saturn’s moon, Titan,” Peter Bedini, a program manager at Johns Hopkins Applied Physics Laboratory, said in a recent talk.

“Seems kind of straightforward. Or arbitrary.”

Dragonfly: A Proposal to Explore Titan, Saturn's Largest Moon, via Quadcopter Johns Hopkins University Applied Physics Laboratory: https://www.youtube.com/watch?v=mk1zVxwq7O4

Proponents of this concept say a quadcopter would be an ideal way to explore Titan, Saturn’s largest moon. The air is thick there, thicker than on Earth. The landscape is varied, interspersed with obstacles — rivers, lakes and seas of liquid methane — that could prove inaccessible for a rover.

The booming popularity of flying drones in recent years makes the technology potentially feasible for interplanetary exploration, too.

“Ten years ago, they were kind of rare things that only enthusiasts experimented with,” said Elizabeth Turtle, a planetary scientist at the Johns Hopkins laboratory, who would serve as the mission’s principal investigator. “Now everyone can have a drone.”

In the past, scientists have suggested exploring the moon with balloons and airplanes. But Titan’s geology — sand dunes, eroded gullies — is more interesting than what is in the air. Dragonfly would fly from place to place, but would spend most of its time performing experiments on the ground.

“In terms of what we're looking for on Saturn, it really hit exactly the sweet spot,” Dr. Turtle said.

A second Titan proposal, Oceanus, is led by Christophe Sotin, the chief scientist for solar system exploration at NASA’s Jet Propulsion Laboratory in Pasadena, Calif., which was Cassini’s home base.

The Oceanus spacecraft would study the moon from orbit, potentially identifying habitable regions for life.

Enceladus

Jonathan I. Lunine, a planetary scientist at Cornell University, was a member of the science team managing the Huygens probe, which traveled to Saturn with Cassini and landed on Titan.

He would be the principal investigator on a proposed mission to revisit Enceladus, a small moon just 313 miles wide. The discovery of geysers shooting from its south pole was a stunning surprise, and now the moon is considered a prime place for look for life.

“Cassini gave us a big pointer to where we need to go to look for life,” Dr. Lunine said. “If we are interested in trying to find life beyond the Earth, that’s the place we need to go, and we know how to do it.”

The proposed spacecraft, called Enceladus Life Finder, would fly through the plumes like Cassini did but with more sophisticated instruments capable of identifying a wide variety of molecules including amino acids, which would hint at signs of life.

NASA is also considering a second Enceladus mission concept called Enceladus Life Signatures and Habitability. That team, led by Christopher P. McKay, an astrobiologist at NASA Ames Research Center in Mountain View, Calif., has not talked in public about its proposal.
Saturn

The Saturn Probe Interior and Atmosphere Explorer would essentially do what Cassini did on Friday: descend into the planet’s atmosphere. But it would go much deeper.

The main part of the mission would end quickly — in about 90 minutes, as the probe parachuted into the atmosphere. It would take measurements of certain elements like helium that are hard to measure.

Never miss an eclipse, a meteor shower, a rocket launch or any other astronomical and space event that's out of this world.

The ratio of helium to hydrogen is a crucial measure indicating how far from the sun a planet formed in the early days of the solar system. Cassini attempted to measure that in its final plunge, but that data, from high in the atmosphere, will not be conclusive.

NASA’s Galileo spacecraft dropped an atmospheric probe into Jupiter in 1995, and this proposal is the “same exact idea as the Galileo probe,” said Amy Simon, an expert on planetary atmospheres at NASA Goddard Space Flight Center in Greenbelt, Md. She would be the principal investigator for the mission.

To understand how the solar system formed, it’s crucial to understand its biggest fixtures. Saturn, of course, is the second largest planet, after Jupiter.

“The two of them together tell you a lot of what happened in the early solar system,” Dr. Simon said. “It will answer those few fundamental questions that we could not do with Cassini.”

 30 
 on: Sep 19, 2017, 04:22 AM 
Started by Rad - Last post by Darja
September 19, 2017

‘Lazy’ ants found to be ‘bench players’ in ant colonies

by Chuck Bednar
Red Orbit

While ants have a reputation for being intensely hard workers, previously published research has actually shown that at any given time, more than one-third of the ants in any given colony spend most of their time doing absolutely nothing – and now scientists think they know why.

In 2015, researchers from the University of Arizona found that approximately 40% of the ants in observed groups were almost totally inactive while their colleagues worked tirelessly to complete tasks essential to the colony’s survival. Further study revealed that these ants were not just being lazy – inactivity was their “specialization,” like how some ants foraged or built nests.

“Interestingly, we found laziness to be a behavior in itself,” Daniel Charbonneau, a grad student in the university’s Entomology and Insect Science department and one of the author of the 2015 paper, said at the time in a statement. At the time, however, the reason for this behavior remained unknown. Now, however, he and his colleagues believe that they’ve solved the mystery.

Writing in a recent edition of the journal PLOS One, Charbonneau, his professor (and co-author of the original study) Anna Dornhaus and Takao Sasaki from the University of Oxford explained that these so-called lazy ants are actually a reserve workforce that step in and pick up the slack if active workers need to be replaced. To borrow a sports analogy, they’re bench players.

“Serving as a replacement workforce is a long-held suspicion about the function of ‘lazy’ ants, but it was just an assumption, and never had been empirically confirmed,” Dornhaus noted last week in a statement. So she and her colleagues conducted experiments to put this notion to the test.

Removed ‘bench players’ are not replaced, researchers found

While observing a colony of ants belonging to the species Temnothorax rugatulus, Charbonneau and his co-authors identified and removed the ants that represented the top 20% of the workforce – those ants deemed to be the most active – to see how the inactive workers would respond.

Within one week, they found that these “bench players” stepped up and took over the roles that had been vacated by the ants that were no missing. These ants increased their levels of activity to match those of the lost workers, and the colony went about business as usual, they explained.

Charbonneau said that the ants being monitored were marked with paint on their head, thorax and abdomen so that they could be tracked in recorded  video footage. Since they studied these ants in the wild, he said that they did not know “how quickly their populations turn over in their natural habitat.” But, he added, “it doesn't take much for a colony to lose a bunch of workers.”

In a separate experiment, Charbonneau and Dornhaus removed the least active 20% of the ants and found that, unlike the hardest workers, these ants were not replaced. In other works, ants that were busy building or foraging were not removed from those tasks to replace lost members of the inactive workforce.

“My speculation is this: Since young workers start out as the most vulnerable members of the colony, it makes sense for them to lay low and be inactive,” said Charbonneau. “And because their ovaries are the most active, they produce eggs, and while they're doing that, they might as well store food. When the colony loses workers, it makes sense to replace them with those ants that are not already busy pursuing other tasks.”

Pages: 1 2 [3] 4 5 ... 10
Video