Grass-feeding butterflies defy wet summers, survey shows

 More than 18,500 meadow browns were counted in 2012 – more than any other species – in the survey by the Wider Countryside butterfly survey. The UK's second wettest year on record was disastrous for sun-loving butterflies but at least three grass-feeding species defied the gloom.

Almost twice as many meadow browns were counted in the UK in 2012 compared with the previous year, and the gatekeeper and ringlet also increased, according to the Wider Countryside butterfly survey (WCBS).

What this brown trio lack in charisma they make up for with their tenacious ability to fly on the darkest of summer days. Their caterpillars also thrived on the luxuriant grass growth promoted by last summer's deluges.

More than 18,500 meadow browns were counted in 2012 – more than any other species – in the WCBS, which involves volunteers searching for butterflies in more than 700 randomly generated 1km squares of the UK countryside.

The ringlet also enjoyed a good year and was found in almost two-thirds of squares compared to half of squares in 2011. The gatekeeper was also more widespread than in 2011.

Zoe Randle, co-ordinator of the WCBS, which is run by Butterfly Conservation, the British Trust for Ornithology and the Centre for Ecology & Hydrology, said she was "totally amazed" by the success of the meadow brown during another calamitous summer for butterflies.

"I thought 2012 would be a complete damp squib and butterfly numbers would be massively down. I had to check the figures to make sure it wasn't a data error," she said of the meadow brown's welcome increase.

The WCBS provides a useful picture of the health of butterfly and insect populations in our ordinary countryside, and not just in nature reserves where insect counts tend to occur. Unfortunately, it is revealing a dramatic loss of butterflies from the wider countryside.

In 2012, recorders saw on average 44 butterflies of four species in each survey, compared with an average of 80 butterflies of eight species in 2009. Big losers were the small tortoiseshell – once a common sight in gardens – with less than half the number counted than in 2011, and the common blue, spotted in 50% fewer 1km squares than in 2011.

According to Randle, the loss of butterflies from our countryside is not simply due to seasonal fluctuations related to bad weather but reflects an increasingly degraded landscape.

"We need more wildlife-friendly agricultural policies and more focused agricultural and woodland management schemes for butterflies," she said. "When we have years like last year with a whole summer of bad weather, that's going to exacerbate the problems these species are already facing."

While some rare butterflies are surviving relatively well in protected nature reserves, once-common species of the wider countryside have suffered a 24% population decline in the first decade of this century.

Three-quarters of Britain's 59 native species of butterfly are declining in number and a countryside completely bereft of butterflies is already a reality: 38 summer visits to the WCBS 1km squares recorded no butterflies at all in 2012.

Source:The Guardian

Compiled by:Maysa Wassouf

Climate change: Soot's role underestimated, says study

Black carbon, or soot, is making a much larger contribution to global warming than previously recognized, according to research.

scientists say that particles from diesel engines and wood burning could be having twice as much warming effect as assessed in past estimates.

They say it ranks second only to carbon dioxide as the most important climate-warming agent.

The research is in the Journal of Geophysical Research-Atmospheres.

Black carbon aerosols have been known to warm the atmosphere for many years by absorbing sunlight. They also speed the melting of ice and snow.

This new study concludes the dark particles are having a warming effect approximately two thirds that of carbon dioxide, and greater than methane.

"The large conclusion is that forcing due to black carbon in the atmosphere is larger," lead author Sarah Doherty told BBC News.

"The value the IPCC gave in their 4th assessment report in 2007 is half of what we are presenting in this report - it's a little bit shocking,"

The researchers say black carbon emissions in Europe and North America have been declining due to restrictions on emissions from diesel engines. But they have been growing steadily in the developing world. However as these type of particles don't last very long in the atmosphere, cutting their number would have an immediate impact on temperatures.

"Reducing emissions from diesel engines and domestic wood and coal fires is a no-brainer as there are tandem health and climate benefits," said Professor Piers Forster from the University of Leeds.

"If we did everything we could to reduce these emissions we could buy ourselves up to half a degree less warming, or a couple of decades of respite," he added.

The report warns that the role of black carbon is complex and can have cooling and warming effects.

"Mitigation is a complex issue because soot is typically emitted with other particles and gases that probably cool the climate," said Prof Forster,

"For instance, organic matter in the atmosphere produced by open vegetation burning likely has a cooling effect. Therefore the net effect of eliminating that source might not give us the desired cooling," he added.

Black carbon is said to be a significant source of rapid warming in the northern United States, Canada, northern Europe and northern Asia. The particles are also said to have an impact on rainfall patterns in the Asian monsoon.

Last year a six nation coalition of countries began a combined effort to curb the impact of short lived climate agents such as black carbon.

Source :BBC

M.W

 

Planets and their sun grow together

Some 450 light-years from Earth, embryonic planets may be feeding tendrils of gas to the newborn star they orbit. The discovery helps explain how a young star can grow even as budding planets suck up much of the gas and dust around it. Without the tendrils replenishing it, the star’s supply of gas would disappear in less than a year.

 

Jupiter and Saturn may have done something similar for the sun in its early days, 4.5 billion years ago. “This is one of the nearest examples of the birth of a solar system,” says Simon Casassus, an astronomer at the University of Chile. He and his colleagues describe the finding online January 2 in Nature.

The star in question is named HD 142527, in the southern constellation Lupus. It’s about twice the mass of the sun but far younger, only about 2 million years old. Astronomers knew it was surrounded by a swirling disk of gas and dust, which has a big clearing in it from about 10 times to 140 times the Earth-sun distance. They think a big budding planet — something like Jupiter in its very early days — might orbit its star at about 90 times the Earth-sun distance, clearing out a gap like a snowplow shoveling roads.

Casassus’ team looked at this gap using the ALMA array of radio telescopes in Chile, which can detect faint emissions from gases such as carbon monoxide. The team found some of this gas drifting through the gap — probably leftover stuff that the protoplanet hadn’t cleared away, Casassus says.

More intriguingly, denser gas formed several filaments stretching across the gap. These streamers are almost certainly guided and shaped by protoplanets embedded within them, Casassus says.

The filaments are faint, says University of Hawaii astronomer Jonathan Williams, but “my gut reaction is that their interpretation is probably correct and that this is an exciting result.”

Simulations of how the gas might flow suggest not one but at least two big protoplanets surround the star. One, of around 10 Jupiter masses, probably orbits at the expected 90 times the Earth-sun distance. A second, of around 4 Jupiter masses, may orbit closer in, at around 40 times the Earth-sun distance. “At this point, we can’t tell how many objects orbit the star,” cautions Sally Dodson-Robinson, an astronomer at the University of Texas at Austin.

Astronomers haven’t yet directly spotted any protoplanets around HD 142527, but they keep looking. The Nature paper relies on one hour’s worth of observations from ALMA; Casassus has six more hours of data that should be arriving on his desk within the next few weeks. “There’s lots more to come,” he says.

Science News Magazine

M.W

 

Climate Warming Unlikely to Cause Near-Term Extinction of Ancient Amazon Trees

The authors of a new study warn that extreme drought and forest fires will impact Amazonia as temperatures rise, and the over-exploitation of the region's resources continues to be a major threat to its future. Conservation policy for the Amazon should remain focused on reducing global greenhouse-gas emissions and preventing deforestation, they said.

The study by University of Michigan evolutionary biologist Christopher Dick and his colleagues demonstrates the surprising age of some Amazonian tree species -- more than 8 million years -- and thereby shows that they have survived previous periods as warm as many of the global warming scenarios forecast for the year 2100.

The paper is scheduled for online publication Dec. 13 in the journal Ecology and Evolution. The new study is at odds with earlier papers, based on ecological niche-modeling scenarios, which predicted tree species extinctions in response to relatively small increases in global average air temperatures.

"Our paper provides evidence that common Amazon tree species endured climates warmer than the present, implying that -- in the absence of other major environmental changes -- they could tolerate near-term future warming under climate change," said Dick, an associate professor of ecology and evolutionary biology and acting director of the U-M Herbarium.

But study co-author Simon Lewis of University College London and the University of Leeds cautioned that "the past cannot be compared directly with the future."

"While tree species seem likely to tolerate higher air temperatures than today, the Amazon forest is being converted for agriculture and mining, and what remains is being degraded by logging and increasingly fragmented by fields and roads," Lewis said. "Species will not move as freely in today's Amazon as they did in previous warm periods, when there was no human influence. Similarly, today's climate change is extremely fast, making comparisons with the past difficult.

"With a clearer understanding of the relative risks to the Amazon forest, we conclude that direct human impacts, such as forest clearance for agriculture or mining, should remain a focus of conservation policy," Lewis said. "We also need more aggressive action to reduce greenhouse gas emissions in order to minimize the risk of drought and fire impacts to secure the future of most Amazon tree species."

Dick and his colleagues used a molecular clock approach to determine the ages of 12 widespread Amazon tree species, including the kapok and the balsa. Then they looked at climatic events that have occurred since those tree species emerged. In general, they inferred that the older the age of the tree species, the warmer the climate it has previously survived.

The researchers determined that nine of the tree species have been around for at least 2.6 million years, seven have been present for at least 5.6 million years, and three have existed in the Amazon for more than 8 million years.

"These are surprisingly old ages," Dick said. "Previous studies have suggested that a majority of Amazon tree species may have originated during the Quaternary Period, from 2.6 million years ago to the present."

The 12 tree species used in the study are broadly representative of the Amazon tree flora. Primary forest collection sites were in central Panama, western Ecuador and Amazonian Ecuador. Additional collections were made in Brazil, Peru, French Guiana and Bolivia. Other plant samples were obtained from herbarium specimens.

 

Science Daily

M.W

Physicist Calculates Field Strengths in the Early Universe

Magnets have practically become everyday objects. Earlier on, however, the universe consisted only of nonmagnetic elements and particles. Just how the magnetic forces came into existence has been researched by Prof. Dr. Reinhard Schlickeiser at the Institute of Theoretical Physics of the Ruhr-Universität Bochum. In the journal Physical Review Letters, he describes a new mechanism for the magnetisation of the universe even before the emergence of the first stars.

No permanent magnets in the early universe

Before the formation of the first stars, the luminous matter consisted only of a fully ionised gas of protons, electrons, helium nuclei and lithium nuclei which were produced during the Big Bang. "All higher metals, for example, magnetic iron could, according to today's conception, only be formed in the inside of stars," says Reinhard Schlickeiser. "In early times therefore, there were no permanent magnets in the Universe." The parameters that describe the state of a gas are, however, not constant. Density and pressure, as well as electric and magnetic fields fluctuate around certain mean values. As a result of this fluctuation, at certain points in the plasma weak magnetic fields formed -- so-called random fields. How strong these fields are in a fully ionised plasma of protons and electrons, has now been calculated by Prof. Schlickeiser, specifically for the gas densities and temperatures that occurred in the plasmas of the early universe.

Weak magnetic fields with large volumes

The result: the magnetic fields fluctuate depending on their position in the plasma, however, regardless of time -- unlike, for example, electromagnetic waves such as light waves, which fluctuate over time. Everywhere in the luminous gas of the early universe there was a magnetic field with a strength of 10^-20 Tesla, i.e. 10 sextillionth of a Tesla. By comparison, the earth's magnetic field has a strength of 30 millionths of a Tesla. In MRI scanners, field strengths of three Tesla are now usual. The magnetic field in the plasma of the early universe was thus very weak, but it covered almost 100 percent of the plasma volume.

Interaction of thermal shock waves and magnetic fields

Stellar winds or supernova explosions of the first massive stars generated shock waves that compressed the magnetic random fields in certain areas. In this way, the fields were strengthened and aligned on a wide-scale. Ultimately, the magnetic force was so strong that it in turn influenced the shock waves. "This explains the balance often observed between magnetic forces and thermal gas pressure in cosmic objects," says Prof. Schlickeiser. The calculations show that all fully ionised gases in the early universe were weakly magnetised. Magnetic fields therefore existed even before the first stars. Next, the Bochum physicist is set to examine how the weak magnetic fields affect temperature fluctuations in the cosmic background radiation.

Source :Science Daily

M.Wassouf