Climatologists offer explanation for widening of Earth’s tropical belt

Recent studies have shown that Earth’s tropical belt — demarcated, roughly, by the Tropics of Cancer and Capricorn — has progressively expanded since at least the late 1970s. Several explanations for this widening have been proposed, such as radiative forcing due to greenhouse gas increase and stratospheric ozone depletion.Now, a team of climatologists, led by researchers at the University of California, Riverside, posits that the recent widening of the tropical belt is primarily caused by multi-decadal sea surface temperature variability in the Pacific Ocean. This variability includes the Pacific Decadal Oscillation (PDO), a long-lived El Nio-like pattern of Pacific climate variability that works like a switch every 30 years or so between two different circulation patterns in the North Pacific Ocean. It also includes, the researchers say, anthropogenic pollutants, which act to modify the PDO.Study results appear March 16 in Nature Geoscience.”Prior analyses have found that climate models underestimate the observed rate of tropical widening, leading to questions on possible model deficiencies, possible errors in the observations, and lack of confidence in future projections,” said Robert J. Allen, an assistant professor of climatology in UC Riverside’s Department of Earth Sciences, who led the study. “Furthermore, there has been no clear explanation for what is driving the widening.”Now Allen’s team has found that the recent tropical widening is largely driven by the PDO.”Although this widening is considered a ‘natural’ mode of climate variability, implying tropical widening is primarily driven by internal dynamics of the climate system, we also show that anthropogenic pollutants have driven trends in the PDO,” Allen said. “Thus, tropical widening is related to both the PDO and anthropogenic pollutants.”Widening concernsTropical widening is associated with several significant changes in our climate, including shifts in large-scale atmospheric circulation, like storm tracks, and major climate zones. For example, in Southern California, tropical widening may be associated with less precipitation.Of particular concern are the semi-arid regions poleward of the subtropical dry belts, including the Mediterranean, the southwestern United States and northern Mexico, southern Australia, southern Africa, and parts of South America. A poleward expansion of the tropics is likely to bring even drier conditions to these heavily populated regions, but may bring increased moisture to other areas.Widening of the tropics would also probably be associated with poleward movement of major extratropical climate zones due to changes in the position of jet streams, storm tracks, mean position of high and low pressure systems, and associated precipitation regimes. An increase in the width of the tropics could increase the area affected by tropical storms (hurricanes), or could change climatological tropical cyclone development regions and tracks.Belt contractionAllen’s research team also showed that prior to the recent (since ~1980 onwards) tropical widening, the tropical belt actually contracted for several decades, consistent with the reversal of the PDO during this earlier time period.”The reversal of the PDO, in turn, may be related to the global increase in anthropogenic pollutant emissions prior to the ~ early 1980s,” Allen said.AnalysisAllen’s team analyzed IPCC AR5 (5th Assessment Report) climate models, several observational and reanalysis data sets, and conducted their own climate model experiments to quantify tropical widening, and to isolate the main cause.”When we analyzed IPCC climate model experiments driven with the time-evolution of observed sea surface temperatures, we found much larger rates of tropical widening, in better agreement to the observed rate–particularly in the Northern Hemisphere,” Allen said. …

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Agroforestry can ensure food security, mitigate effects of climate change in Africa

Agroforestry can help to achieve climate change mitigation and adaptation while at the same time providing livelihoods for poor smallholder farmers in Africa.Scientists at the World Agroforestry Centre (ICRAF) say agroforestry — which is an integrated land use management technique that incorporates trees and shrubs with crops and livestock on farms — could be a win-win solution to the seemingly difficult choice between reforestation and agricultural land use, because it increases the storage of carbon and may also enhance agricultural productivity.In a special issue of Current Opinion in Environmental Sustainability, scientists say that in most parts of Africa, climate change mitigation focuses on reforestation and forest protection however, such efforts to reduce deforestation conflict with the need to expand agricultural production in Africa to feed the continent’s growing population.Agriculture in Africa is dominated by smallholder farmers. Their priority is to produce enough food. Under such circumstances, any measures that will be put in place to mitigate the effects of climate change should also improve food production.”This mixture shows the role that agroforestry can play in addressing both climate mitigation and adaptation in primarily food-focused production systems of Africa” says Dr. Cheikh Mbow, Senior Scientist, Climate Change and Development at the World Agroforestry Centre (ICRAF) and lead author of the article.”It has been demonstrated by science that if you develop agroforestry it has the potential to buffer the impact of climate change. For example, a farm with trees will suffer less to the impacts of climate change because it will absorb some of these impacts so agroforestry is a good response to develop resilience of agrosystems to the challenges brought about by climate change” he says.The report however notes that for farmers to incorporate trees in their farms there is need to revise the cultivation methods and provide them with some support to ensure swift adoption.Agroforestry is one of the most common land use systems across landscapes and agroecological zones in Africa but need much more adoption in order to increase the impact on food security. With food shortages and increased threats of climate change, interest in agroforestry is gathering for its potential to address various on-farm adaptation needs. “The failure of extension services in poor African countries limits the possibility to scale up innovations in agroforestry for improved land use systems .”The scientists conclude that agroforestry should therefore attract more attention in global agendas on climate change mitigation because of its positive social and environmental impacts.Story Source:The above story is based on materials provided by World Agroforestry Centre (ICRAF). Note: Materials may be edited for content and length.

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In grasslands remade by humans, animals may protect biodiversity: Grazers let in the light, rescue imperiled plants

A comparative study of grasslands on six continents suggests there may be a way to counteract the human-made overdose of fertilizer that threatens to permanently alter the biodiversity of the world’s native prairies.The solution is one that nature devised: let grazing animals crop the excess growth of fast growing grasses that can out-compete native plants in an over-fertilized world. And grazing works in a way that is also natural and simple. The herbivores, or grazing and browsing animals, feed on tall grasses that block sunlight from reaching the ground, making the light available to other plants.That’s the key finding of a five-year study carried out at 40 different sites around the world and scheduled for online publication March 9, 2014 in the journal Nature. More than 50 scientists belonging to the Nutrient Network, a team of scientists studying grasslands worldwide, co-authored the study.”This study has tremendous significance because human activities are changing grasslands everywhere,” said study co-author Daniel S. Gruner, associate professor of entomology at the University of Maryland. “We’re over-fertilizing them, and we’re adding and subtracting herbivores. We have a worldwide experiment going on, but it’s completely uncontrolled.”Gruner, a member of the Nutrient Network (which participants have nicknamed NutNet) since its founding in 2006, helped plan the worldwide study and analyze its results. Elizabeth Borer of the University of Minnesota was the study’s lead author.The U.N. Food and Agricultural Organization estimates that grasslands cover between one-fifth and two-fifths of the planet’s land area and are home to more than one-tenth of humankind. But like all plant communities, grasslands are suffering from too much fertilizer.As humans burn fossil fuels, dose crops with chemical fertilizers, and dispose of manure from livestock, they introduce extra nitrogen and other nutrients into the soil, air and water. …

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The parasite that escaped out of Africa: Tracing origins of malaria parasite

An international team of scientists has traced the origin of Plasmodium vivax, the second-worst malaria parasite of humans, to Africa, according to a study published this week in Nature Communications. Until recently, the closest genetic relatives of human P. vivax were found only in Asian macaques, leading researchers to believe that P. vivax originated in Asia.The study, led by researchers from the Perelman School of Medicine at the University of Pennsylvania, found that wild-living apes in central Africa are widely infected with parasites that, genetically, are nearly identical to human P. vivax.This finding overturns the dogma that P. vivax originated in Asia, despite being most prevalent in humans there now, and also solves other vexing questions about P. vivax infection: how a mutation conferring resistance to P. vivax occurs at high frequency in the very region where this parasite seems absent and how travelers returning from regions where almost all humans lack the receptor for P. vivax can be infected with this parasite.Of Ape and Human ParasitesMembers of the labs of Beatrice Hahn, MD, and George Shaw, MD, PhD, both professors of Medicine and Microbiology at Penn, in collaboration with Paul Sharp, PhD, an evolutionary biologist from the University of Edinburgh, and Martine Peeters, PhD, a microbiologist from the Institut de Recherche pour le Dveloppement and the University of Montpellier, tested over 5,000 ape fecal samples from dozens of field stations and sanctuaries in Africa for P. vivax DNA. …

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HIV drug used to reverse effects of virus that causes cervical cancer

A commonly-used HIV drug has been shown to kill off the human papilloma virus (HPV) that leads to cervical cancer in a world-first clinical trial led by The University of Manchester with Kenyatta National Hospital (KNH) in Nairobi.Drs Ian and Lynne Hampson, from the University’s Institute of Cancer Sciences and Dr Innocent Orora Maranga, Consultant in Obstetrics and Gynaecology at KNH in Nairobi examined Kenyan women diagnosed with HPV positive early stage cervical cancer who were treated with the antiviral HIV drug lopinavir in Kenya.The study looked at 40 women with both high and low-grade pre-cancerous disease of the cervix and the antiviral drug, normally used orally to treat HIV, was self-applied directly to the cervix as a pessary.The results, due to be presented at two international scientific conferences later this month and next, showed a high proportion of women diagnosed with HPV positive high-grade disease returned to normal following a short course of the new treatment. The findings build on previous peer-reviewed laboratory based research carried out by Drs Hampson and will be submitted to a journal soon.They have been described by an independent leading specialist in gynaecological cancer as very impressive. The 40 women, who were all HPV positive with either high-grade, borderline or low grade disease, were treated with one capsule of the antiviral drug twice a day for 2 weeks.Repeat cervical smears showed a marked improvement within one month of the treatment although after three months, there was a definite response. Out of 23 women initially diagnosed with high-grade disease, 19 (82.6%) had returned to normal and two now had low-grade disease giving an overall positive response in 91.2%.of those treated.Furthermore the 17 women initially diagnosed with borderline or low-grade disease also showed similar improvement. Photographic images of the cervix before and after treatment showed clear regression of the cervical lesions and no adverse reactions were reported.Dr Ian Hampson said: “For an early stage clinical trial the results have exceeded our expectations. We have seen women with high-grade disease revert to a normal healthy cervix within a comparatively short period of time.”We are convinced that further optimization of the dose and treatment period will improve the efficacy still further.”It is our hope that this treatment has the potential to revolutionize the management of this disease most particularly in developing nations such as Kenya.”Cervical cancer is caused by infection with human papilloma virus (HPV) and is more than five times more prevalent in East Africa than the UK. In many developing countries, HPV-related cervical cancer is still one of the most common women’s cancers accounting for approximately 290,000 deaths per year worldwide. The same virus also causes a significant proportion of cancers of the mouth and throat in both men and women and this disease is showing an large increase in developed countries, such as the UK, where it is now more than twice as common as cervical cancer.Dr Lynne Hampson said: “Current HPV Vaccines are prophylactics aimed at preventing the disease rather than curing or treating symptoms. Other than surgery, as yet there is no effective treatment for either HPV infection or the pre-cancerous lesion it causes which is why these results are so exciting.”Further work is needed but it looks as though this might be a potential treatment to stop early stage cervical cancer caused by HPV.”On a global scale HPV is the most common sexually transmitted disease. Although in the developed world vaccination programmes against HPV are well underway, these are not effective in women already infected with the virus.The current vaccines do not protect against all types of HPV and they are expensive, which can limit their use in countries with low resources. …

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Geographic variation of human gut microbes tied to obesity

People living in cold, northern latitudes have bacteria in their guts that may predispose them to obesity, according to a new study by researchers at the University of California, Berkeley, and the University of Arizona, Tucson.The researchers’ analysis of the gut microbes of more than a thousand people from around the world showed that those living in northern latitudes had more gut bacteria that have been linked to obesity than did people living farther south.The meta-analysis of six earlier studies was published this month in the online journal Biology Letters by UC Berkeley graduate student Taichi Suzuki and evolutionary biology professor Michael Worobey of the University of Arizona.”People think obesity is a bad thing, but maybe in the past getting more fat and more energy from the diet might have been important to survival in cold places. Our gut microbes today might be influenced by our ancestors,” said Suzuki, noting that one theory is that obesity-linked bacteria are better at extracting energy from food. “This suggests that what we call ‘healthy microbiota’ may differ in different geographic regions.””This observation is pretty cool, but it is not clear why we are seeing the relationship we do with latitude,” Worobey said. “There is something amazing and weird going on with microbiomes.”To Worobey, the results are fascinating from an evolutionary biology perspective. “Maybe changes to your gut community of bacteria are important for allowing populations to adapt to different environmental conditions in lots of animals, including humans,” he said.Body size increases with latitudeSuzuki proposed the study while rotating through Worobey’s lab during his first year as a graduate student at the University of Arizona. Studies of gut microbes have become a hot research area among scientists because the proportion of different types of bacteria and Archaea in the gut seems to be correlated with diseases ranging from diabetes and obesity to cancer. In particular, the group of bacteria called Firmicutes seems to dominate in the intestines of obese people — and obese mice — while a group called Bacteroidetes dominates in slimmer people and mice.Suzuki reasoned that, since animals and humans in the north tend to be larger in size — an observation called Bergmann’s rule — then perhaps their gut microbiota would contain a greater proportion of Firmicutes than Bacteriodetes. While at the University of Arizona, and since moving to UC Berkeley, Suzuki has been studying how rodents adapt to living at different latitudes.”It was almost as a lark,” Woroby said. “Taichi thought that if Firmicutes and Bacteroidetes are linked to obesity, why not look at large scale trends in humans. When he came back with results that really showed there was something to it, it was quite a surprise.”Suzuki used data published in six previous studies, totaling 1,020 people from 23 populations in Africa, Europe, North and South America and Asia. …

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Madagascar sells first forest carbon credits to Microsoft

The Government of Madagascar has approved carbon sales with Microsoft and its carbon offset partner, The CarbonNeutral Company, and Zoo Zurich. The carbon credit sales will support the Government of Madagascar’s REDD+ Project (Reducing Emissions from Deforestation and Forest Degradation “plus” conservation) in the Makira Natural Park and mark the first sale of government-owned REDD+ credits in Africa.Through carbon credit sales from avoided deforestation, the Makira REDD+ Project will finance the long-term conservation of one of Madagascar’s most pristine remaining rainforest ecosystems harboring rare and threatened plants and animals while improving community land stewardship and supporting the livelihoods of the local people.Through a unique funding distribution mechanism designed by WCS and the Government of Madagascar, the funds from carbon sales will be used by the Government of Madagascar for conservation, capacity building, and enforcement activities, and by WCS to manage the Makira Natural Park. The largest share of the sale — half of the proceeds — will go to supporting local communities in the areas surrounding Makira for education, human health and other beneficial projects.”The Government of Madagascar is thrilled to have played the role of pioneer in carbon sales in Africa. Makira is a highly valued part of our natural heritage and the revenues from this sale will not only protect this oustanding area, but represent an important step in our plan to develop sustainable sources of financing for the whole protected area network. We hope that other organizations will follow the lead of Microsoft, The CarbonNeutral Company, and Zoo Zurich and join us in this effort to conserve Madagascar’s unique biodiversity through the sale of future carbon credits,” said Pierre Manganirina Randrianarisoa the Secretary General of the Ministry of Environment and Forests.Said WCS President and CEO Cristin Samper “These sales represent a first for WCS, a first for Africa, and a first for Madagascar in advancing the use of carbon credits to fight climate change while protecting biodiversity and human livelihoods. We are thankful to Microsoft, The CarbonNeutral Company and Zoo Zurich, and we look forward to future purchases by other forward-thinking organizations.”Said Rob Bernard, Chief Environmental Strategist at Microsoft: “Supporting forest conservation and community building projects like Makira is an important part of Microsoft’s strategy to reduce its environmental impact, support sustainable economic growth, improve health and education, and address societal challenges. The project’s important role in protecting a crucial area of biodiversity value also aligns with Microsoft’s own focus on using technology, information and research to develop new approaches and solutions to sustainability.”Said Jonathan Shopley, Managing Director of The CarbonNeutral Company: “Increasingly our clients are looking for opportunities to manage the entire environmental impact of their organisation, driven by the need to build resilience in their supply chains. The Makira project enables clients to do this by selling carbon credits while also delivering biodiversity value and community support.”Makira contains an estimated one percent of the world’s biodiversity including 20 lemur species, hundreds of species of birds, and thousands of plant varieties, including many found nowhere else on earth. The Makira forest spans nearly 400,000 hectares (more than 1,500 square miles), making it one of the largest remaining intact blocks of rainforest in Madagascar. In addition, Makira’s forests serve as a zone of watershed protection, providing clean water to over 250,000 people in the surrounding landscape.WCS, which has worked in Makira since 2003, is the delegated manager of the park and is responsible for implementing the REDD+ project that aims to safeguard the Makira Natural Park, one of Madagascar’s largest protected areas.Last September the Government of Madagascar and WCS announced that 710,588 carbon credits had been certified for sale from the Makira Forest REDD+ Project. …

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Crocodilians can climb trees and bask in the tree crowns

When most people envision crocodiles and alligators, they think of them waddling on the ground or wading in water — not climbing trees. However, a University of Tennessee, Knoxville, study has found that the reptiles can climb trees as far as the crowns.Vladimir Dinets, a research assistant professor in the Department of Psychology, is the first to thoroughly study the tree-climbing and -basking behavior. The research is published in the journal Herpetology.Dinets and his colleagues observed crocodilian species on three continents — Australia, Africa and North America — and examined previous studies and anecdotal observations. They found that four species climbed trees — usually above water — but how far they ventured upward and outward varied by their sizes. The smaller crocodilians were able to climb higher and further than the larger ones. Some species were observed climbing as far as four meters high in a tree and five meters down a branch.”Climbing a steep hill or steep branch is mechanically similar, assuming the branch is wide enough to walk on,” the authors wrote. “Still, the ability to climb vertically is a measure of crocodiles’ spectacular agility on land.”The crocodilians seen climbing trees, whether at night or during the day, were skittish of being approached, jumping or falling into the water when an approaching observer was as far as 10 meters away. This response led the researchers to believe that the tree climbing and basking are driven by two conditions: thermoregulation and surveillance of habitat.”The most frequent observations of tree-basking were in areas where there were few places to bask on the ground, implying that the individuals needed alternatives for regulating their body temperature,” the authors wrote. “Likewise, their wary nature suggests that climbing leads to improved site surveillance of potential threats and prey.”The data suggests that at least some crocodilian species are able to climb trees despite lacking any obvious morphological adaptations to do so.”These results should be taken into account by paleontologists who look at changes in fossils to shed light on behavior,” said Dinets. “This is especially true for those studying extinct crocodiles or other Archosaurian taxa.”Dinets collaborated with Adam Britton from Charles Darwin University in Australia and Matthew Shirley from the University of Florida.Research by Dinets published in 2013 found another surprising crocodilian characteristic — the use of lures such as sticks to hunt prey. …

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Whales bearing young and humans drilling for oil in same African waters

Scientists with the Wildlife Conservation Society, Oregon State University, Stanford University, Columbia University, and the American Museum of Natural History have found that humpback whales swimming off the coast of western Africa encounter more than warm waters for mating and bearing young; new studies show that the whales share these waters with offshore oil rigs, major shipping routes, and potentially harmful toxicants.With the aid of satellite tags affixed to more than a dozen whales, the researchers have quantified the amount of overlap between hydrocarbon exploration and extraction, environmental toxicants, shipping lanes, and humpback whales occurring in their nearshore breeding areas. The scientists also identified additional parts of the whales’ breeding range and migratory routes to sub-Antarctic feeding grounds.The study appears in the latest edition of the journal Conservation Biology. The authors are: Howard Rosenbaum of the Wildlife Conservation Society and the American Museum of Natural History; Sara Maxwell of Stanford University; Francine Kershaw of Columbia University; and Bruce Mate of Oregon State University.”Throughout numerous coastal and offshore areas, important whale habitats and migration routes are increasingly overlapping with industrial development, a scenario we have quantified for the first time in the eastern South Atlantic,” said Dr. Howard Rosenbaum, Director of WCS’s Ocean Giants Program. “Studies such as this one are crucial for identifying important habitats for humpback whales and how to best protect these populations from potential impacts associated with hydrocarbon exploration and production, shipping, and other forms of coastal and offshore activities.”Rosenbaum added: “From understanding which habitats are most important to tracking their migrations, our work provides great insights into the current issues confronting these whales and how to best engage ocean industries to better protect and ensure the recovery of these leviathans.”Growing to approximately 50 feet in length, humpback whales are characterized by their long pectoral fins, acrobatic behavior, and haunting songs. Like other great whales, the humpback whale was hunted for centuries by commercial whaling fleets, with experts estimating a reduction of possibly 90 percent in its global population size. The International Whaling Commission has protected humpback whales globally from commercial whaling since 1968.While migration patterns of humpbacks have been the subject of extensive study in other ocean basins and regions, the migratory behaviors of humpbacks along the western African coast in the eastern South Atlantic are poorly described. To better understand the movements of humpback whales in the Gulf of Guinea, the researchers deployed satellite tags on 15 individual animals off the coast of Gabon between August and September of 2002.”This study demonstrates clearly that all of the countries on the west coast of Africa need to work together on a range-wide humpback whale conservation strategy and consider the possibility of creating a whale sanctuary,” said Professor Lee White, CBE, director of Gabon’s National Parks Agency. “Gabon supports the concept of a South Atlantic Whale Sanctuary and will continue to work with other nations in the region to this end.”Dr. Bruce Mate, who pioneered the satellite-monitored radio tagging of large whales, said: “This technology allows the science and conservation communities to discover detailed seasonal migration routes, timing and destinations, so we can characterize these important habitats and reduce potential impacts of human activities, even in the harshest possible marine environments.”The major goal of the study was to elucidate the unknown migratory movement of whales from breeding areas off western Africa to areas where the whales likely feed in Antarctic or sub-Antarctic waters. …

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Sucker-footed fossils broaden bat map: Fossilized teeth show bat family belongs to primitive lineage, had broad range

Today, Madagascar sucker-footed bats live nowhere outside their island home, but new research shows that hasn’t always been the case. The discovery of two extinct relatives in northern Egypt suggests the unusual creatures, which evolved sticky footpads to roost on slick surfaces, are primitive members of a group of bats that evolved in Africa and ultimately went on to flourish in South America.A team of researchers described the two bat species from several sets of fossilized jawbones and teeth unearthed in the Sahara. The findings, reported Feb. 4 in the open-access journal PLOS ONE, represent the first formal description of the family in the fossil record and show the sucker-footed bat family to be at least 36 million years older than previously known.”We’ve assumed for a long time that they were an ancient lineage based on DNA sequence studies that have placed them close to very old groups in the bat family tree,” said Nancy Simmons, co-author and curator-in-charge of the American Museum of Natural History’s Mammalogy Department. But until now, scientists lacked any fossil evidence to confirm it.The discovery also shows that, like many island-dwelling, relict species, sucker-footed bats have not always been confined to their present range — they once swooped through the African skies.Today, the sucker-footed bats consist of two species, Myzopoda aurita and M. schliemanni, endemic to Madagascar. In contrast to almost all other bats, they don’t cling upside-down to cave ceilings or branches. Sucker-footed bats roost head-up, often in the furled leaves of the traveler’s palm, a plant in the bird-of-paradise family. To stick to such a smooth surface, the bats evolved cup-like pads on their wrists and ankles. Scientists previously suspected the pads held the bats up by suction, but recent research has demonstrated the bats instead rely on wet adhesion, like a tree frog.”The fossils came from a fascinating place out in the Egyptian desert,” said Gregg Gunnell, director of the Duke University Lemur Center’s Division of Fossil Primates. …

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Carbon cycle models underestimate indirect role of animals

Oct. 16, 2013 — Animal populations can have a far more significant impact on carbon storage and exchange in regional ecosystems than is typically recognized by global carbon models, according to a new paper authored by researchers at the Yale School of Forestry & Environmental Studies (F&ES).In fact, in some regions the magnitude of carbon uptake or release due to the effects of specific animal species or groups of animals — such as the pine beetles devouring forests in western North America — can rival the impact of fossil fuel emissions for the same region, according to the paper published in the journal Ecosystems.While models typically take into account how plants and microbes affect the carbon cycle, they often underestimate how much animals can indirectly alter the absorption, release, or transport of carbon within an ecosystem, says Oswald Schmitz, the Oastler Professor of Population and Community Ecology at F&ES and lead author of the paper. Historically, the role of animals has been largely underplayed since animal species are not distributed globally and because the total biomass of animals is vastly lower than the plants that they rely upon, and therefore contribute little carbon in the way of respiration.”What these sorts of analyses have not paid attention to is what we call the indirect multiplier effects,” Schmitz says. “And these indirect effects can be quite huge — and disproportionate to the biomass of the species that are instigating the change.”In the paper, “Animating the Carbon Cycle,” a team of 15 authors from 12 universities, research organizations and government agencies cites numerous cases where animals have triggered profound impacts on the carbon cycle at local and regional levels.In one case, an unprecedented loss of trees triggered by the pine beetle outbreak in western North America has decreased the net carbon balance on a scale comparable to British Columbia’s current fossil fuel emissions.And in East Africa, scientists found that a decline in wildebeest populations in the Serengeti-Mara grassland-savanna system decades ago allowed organic matter to accumulate, which eventually led to about 80 percent of the ecosystem to burn annually, releasing carbon from the plants and the soil, before populations recovered in recent years.”These are examples where the animals’ largest effects are not direct ones,” Schmitz says. “But because of their presence they mitigate or mediate ecosystem processes that then can have these ramifying effects.””We hope this article will inspire scientists and managers to include animals when thinking of local and regional carbon budgets,” said Peter Raymond, a professor of ecosystem ecology at the Yale School of Forestry & Environmental Studies.According to the authors, a more proper assessment of such phenomena could provide insights into management schemes that could help mitigate the threat of climate change.For example, in the Arctic, where about 500 gigatons of carbon is stored in permafrost, large grazing mammals like caribou and muskoxen can help maintain the grasslands that have a high albedo and thus reflect more solar energy. In addition, by trampling the ground these herds can actually help reduce the rate of permafrost thaw, researchers say.”It’s almost an argument for rewilding places to make sure that the natural balance of predators and prey are there,” Schmitz says. “We’re not saying that managing animals will offset these carbon emissions. What we’re trying to say is the numbers are of a scale where it is worthwhile to start thinking about how animals could be managed to accomplish that.”

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The African green revolution at the tipping point

Oct. 15, 2013 — In some areas of Africa, farmers, scientists and policymakers are beginning to win the war on hunger, says Pedro Sanchez, PhD. Several factors have come together in recent years to tip the scales and increase food production.Share This:Sanchez will present “The African Green Revolution at the Tipping Point,” on Tuesday, Nov. 5, 2013 at 8:45 AM. The presentation is part of the American Society of Agronomy, Crop Science Society of America, and the Soil Science Society of America Annual Meetings, Nov. 3-6 in Tampa, Florida. The theme of this year’s conference is “Water, Food, Energy, & Innovation for a Sustainable World.” Members of the media receive complimentary registration to the joint meetings.According to Sanchez, not only will African farmers in countries like Nigeria, Ethiopia, Tanzania, Ghana and Malawi will be able to sell more food this year, but they will have enough to feed their own families. “All factors are moving along the value chain” says Sanchez, including policies and subsidies, credit guarantees and the creation of buyer groups. Agronomic improvements, bringing fertilizer and better seeds, are the entry point of the success. “In order for us to move Africa above this level of success, we will need to implement agricultural technologies,” says Sanchez. …

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New methods increases food and bioenergy production from cassava

Sep. 24, 2013 — New ways to utilize starch from cassava can provide food to an additional 30 million people without taking more arable land than today. By 2030 the figure will be 100 million. In addition, the same land can also contribute to an increased production of bioenergy. This is shown in a new study from researchers at the Swedish University of Agricultural Sciences (SLU) and China Agricultural University (CAU).Cassava or manioc (Manihot esculenta Crantz.) is grown for its high starch content. The large tubers are very starchy and processed into flour or semolina (tapioca). This is the staple food for between 0.5-1 billion people in Africa, Latin America and Asia. The plant is grown on about 19 million hectares of land.There are also strong interests to increase the use of cassava starch for industrial use. This can reduce the amount of food or result in even more land being utilized for production. Researchers at SLU and CAU have found that discarded stems contain surprisingly large amounts of starch, up to 30% of dry mass. …

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Genetic study pushes back timeline for first significant human population expansion

Sep. 24, 2013 — About 10,000 years ago, the Neolithic age ushered in one of the most dramatic periods of human cultural and technological transition, where independently, different world populations developed the domestication of plants and animals. The hunter-gatherers gave rise to herders and farmers. Changes to a more sedentary lifestyle and larger settlements are widely thought to have contributed to a worldwide human population explosion, from an estimated 4-6 million people to 60-70 million by 4,000 B.C.Share This:Now, researchers Aiméa, et al., have challenged this assumption using a large set of populations from diverse geographical regions (20 different genomic regions and mitochondrial DNA of individuals from 66 African and Eurasian populations), and compared their genetic results with archaeological findings. The dispersal and expansion of Neolithic culture from the Middle East has recently been associated with the distribution of human genetic markers.They conclude that the first significant expansion of human populations appears to be much older than the emergence of farming and herding, dating back to the Paleolithic (60,000-80,000 years ago) rather than Neolithic age. Therefore, hunter-gatherer populations were able to thrive with cultural and social advances that allowed for the expansion. The authors also speculate that this Paleolithic human population expansion may be linked to the emergence of newer, more advanced hunting technologies or a rapid environmental change to dryer climates.Finally, they also suggest that strong Paleolithic expansions may have favored the emergence of sedentary farming in some populations during the Neolithic. Indeed, the authors also demonstrate that the populations who adopted a sedentary farming lifestyle during the Neolithic had previously experienced the strongest Paleolithic expansions. Conversely, contemporary nomadic herder populations in Eurasia experienced moderate Paleolithic expansions, and no expansions were detected for nomadic hunter-gatherers in Africa. “Human populations could have started to increase in Paleolithic times, and strong Paleolithic expansions in some populations may have ultimately favored their shift toward agriculture during the Neolithic,” said Aiméa.Share this story on Facebook, Twitter, and Google:Other social bookmarking and sharing tools:|Story Source: The above story is based on materials provided by Molecular Biology and Evolution (Oxford University Press), via EurekAlert!, a service of AAAS. …

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Are banana farms contaminating Costa Rica’s crocs?

Sep. 19, 2013 — Shoppers spend over £10 billion on bananas annually and now this demand is being linked to the contamination of Central America’s crocodilians. New research, published in Environmental Toxicology and Chemistry, analyses blood samples from spectacled caiman in Costa Rica and finds that intensive pesticide use in plantations leads to contaminated species in protected conservation areas.”Banana plantations are big business in Costa Rica, which exports an estimated 1.8 million tonnes per year; 10% of the global total,” said author Paul Grant from Stellenbosch University, South Africa. “The climate of the country’s North East is ideal for bananas; however, the Rio Suerte, which flows through this major banana producing area, drains into the Tortuguero Conservation Area.”Tortuguero is home to the spectacled caiman (Caiman crocodilus), one of the most common species of crocodilian in Central America. This freshwater predator is known to be highly adaptive, feeding on fish, crustaceans and in the case of larger specimens, wild pigs.Due to the increased global demand for fruit, pesticide use has more than doubled across Central America in the past twenty years. In Costa Rica, which ranks second in the world for intensity of pesticide use, the problem of contamination is compounded by environmental conditions and lax enforcement of regulations.”Frequent heavy rains can wash pesticides from plantation areas, leading to contamination and the reapplication of sprays to the crops,” said Grant. “Without adequate enforcement of regulations dangerous practices such as aerial spraying close to streams or washing application equipment in rivers also contributes to contamination downstream.”The team collected blood samples from 14 adult caiman and analyzed them for traces of 70 types of pesticide. Caiman within the high intensity banana crop watershed of Rio Suerte had higher pesticide burdens relative to other more remote locations.The nine pesticides detected in the caiman blood were identified as insecticides. Of these seven were listed as Persistent Organic Pollutants (POPS), banned under the 2011 Stockholm Convention.”Caiman near banana plantations had higher pesticide burdens and lower body condition,” said Grant. “This suggests that either pesticides pose a health risk to caiman, or that pesticides harm the habitat and food supply of caiman, thereby reducing the health of this predator.”As long-lived species atop the food chain crocodilians provide an integrated assessment of the fate of pesticides in tropical areas and can be indicative of pesticide damage throughout the ecosystem.”Caiman and other aquatic species have been exposed to pesticides from upstream banana plantations, even in remote areas of a national wilderness area,” concluded Grant. …

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How red crabs on Christmas Island speak for the tropics

Oct. 10, 2013 — Each year, the land-dwelling Christmas Island red crab takes an arduous and shockingly precise journey from its earthen burrow to the shores of the Indian Ocean where weeks of mating and egg laying await.The crabs represent species that do not factor into a lot of climate-change research. The majority of studies focus on changes in temperate climates, such as the future severity and duration of summers and winters. Tropical animals migrate in response to wet-dry seasons. If fluctuations in rainfall become more extreme and frequent with climate change, then scores of animals could be in trouble.Native to the Australian territories of Christmas Island and the Cocos (Keeling) Islands, millions of the crabs start rolling across the island roads and landscape in crimson waves when the November rains begin. After a two-week scuttle to the sea, the male crab sets up and defends a mating burrow for himself and a female of his kind, the place where she will incubate their clutch for another two weeks. Before the morning of the high tide that precedes the December new moon, the females must emerge to release their millions of eggs into the ocean. A month later, the next generation of crabs comes ashore.But a lack of rain can delay or entirely cancel this meticulous process, according to research conducted through Princeton University that could help scientists understand the consequences of climate change for the millions of migratory animals in Earth’s tropical zones.The researchers report in the journal Global Change Biology that the crabs’ reproductive cycle tracked closely with the amount and timing of precipitation. Writ large, these findings suggest that erratic rainfall could be detrimental to animals that migrate with the dry-wet seasonal cycle that breaks up the tropical year, the researchers report. If fluctuations in rainfall become more extreme and frequent with climate change, then scores of animals could be in trouble — not just the migrators themselves, but also the creatures reliant on them for food.Lead author Allison Shaw, who conducted the work as a Princeton doctoral student in ecology and evolutionary biology, explained that what scientists understand about the possible impact of a warming planet on animal movement is dominated by studies of how creatures that migrate with the summer-to-winter seasonal shifts of Europe and North America will be affected by changes such as the severity and duration of summers and winters. …

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Precision agriculture for small scale farming systems

Oct. 8, 2013 — Raj Khosla, PhD, and other agronomists have demonstrated internationally that working closely with farmers can improve crop yields. The principles are the same no matter the location: use the right input, at the right time, at the right place, and in the right amount. How those principles are applied varies from field to field, country to country and farmer to farmer, but almost always impacts outcomes.Share This:Khosla will present “Precision Agriculture for Small Scale Farming Systems” on Wednesday, Nov. 6, 2013 at 9:30 AM. The presentation is part of the American Society of Agronomy, Crop Science Society of America, and the Soil Science Society of America Annual Meetings, Nov. 3-7 in Tampa, Florida. The theme of this year’s conference is “Water, Food, Energy, & Innovation for a Sustainable World” (https://www.acsmeetings.org/). Members of the media receive complimentary registration to the joint meetings.According to Khosla, “precision agriculture is a grossly misunderstood field, due to its development over time in large scale farming systems. The principles and concepts of precision agriculture are not only for large farms using large equipment. …

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Paleorivers across Sahara may have supported ancient human migration routes

Sep. 11, 2013 — Three ancient river systems, now buried, may have created viable routes for human migration across the Sahara to the Mediterranean region about 100,000 years ago, according to research published September 11 in the open access journal PLOS ONE by Tom Coulthard from the University of Hull, UK, and colleagues from other institutions.Share This:Simulating paleoclimates in the region, the researchers found quantitative evidence of three major river systems that likely existed in North Africa 130,000-100,000 years ago, but are now largely buried by dune systems in the desert. When flowing, these rivers likely provided fertile habitats for animals and vegetation, creating ‘green corridors’ across the region. At least one river system is estimated to have been 100 km wide and largely perennial. The Irharhar river, westernmost of the three identified, may represent a likely route of human migration across the region. In addition to rivers, the researchers’ simulations predict massive lagoons and wetlands in northeast Libya, some of which span over 70,000-square kilometers.”It’s exciting to think that 100,000 years ago there were three huge rivers forcing their way across a 1000km of the Sahara desert to the Mediterranean — and that our ancestors could have walked alongside them” said Coulthard.Previous studies have shown that people travelled across the Saharan mountains toward more fertile Mediterranean regions, but when, where and how they did so is a subject of debate. Existing evidence supports the possibilities of a single trans-Saharan migration, many migrations along one route, or multiple migrations along several different routes. The existence of ‘green corridors’ that provided water and food resources were likely critical to these events, but their location and the amount of water they carried is not known. The simulations provided in this study aim to quantify the probability that these routes may have been viable for human migration across the region.Share this story on Facebook, Twitter, and Google:Other social bookmarking and sharing tools:|Story Source: The above story is based on materials provided by Public Library of Science. Note: Materials may be edited for content and length. …

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Surprising underwater-sounds: Humpback whales also spend their winter in Antarctica

Sep. 9, 2013 — Biologists and physicists from the Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research, found out that not all of the Southern Hemisphere humpback whales (Megaptera novaeangliae) migrate towards the equator at the end of the Antarctic summer. Part of the population remains in Antarctic waters throughout the entire winter. The scientists report this in a current issue of scientific journal PLOS ONE. This surprising discovery based on underwater recordings from the Antarctic acoustic observatory PALAOA. It is located near the research base Neumayer Station III on the ice shelf and regularly records underwater sounds of humpback whales even in the austral winter months.Sometimes even scientists need the crucial little quantum of luck to obtain new research ideas. For instance Ilse Van Opzeeland, a marine biologist and expert on large whales at the Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research (AWI). As she unlocked the door to her office one April morning and, as usual, switched on the live stream of PALAOA, the underwater acoustic observatory, the loudspeakers suddenly resounded with the calls of humpback whales — and this at a time during which the marine mammals should long have been swimming 7,000 kilometres further away in the warmer waters off Africa. “I was totally surprised, because the textbook-opinion until that day was that humpback whales migrate to Antarctic waters only in the austral summer months. And even then, standing believes were that they would only be feeding on krill in the ice-free regions around 60 degrees south latitude. …

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New insight into how Cheetahs catch their prey

Sep. 5, 2013 — A new research study has revealed that the cheetah, the world’s fastest land animal, matches and may even anticipate the escape tactics of different prey when hunting, rather than just relying on its speed and agility as previously thought.The study, which has just been published in the Royal Society Journal Biology Letters was carried out by a team of researchers from Queen’s University Belfast, in collaboration with other Institutions in the UK (University of Aberdeen, University of Swansea, Institute of Zoology, Zoological Society of London, University of Oxford), and elsewhere (North Carolina State University, The Lewis Foundation, South African National Parks, Earth and OCEAN Technologies, Kiel, Germany).The research team used GPS and accelerometer data loggers deployed on cheetahs, along with traditional observation methods. The study was funded by a Royal Society International Joint Project grant, a NERC New Investigator award and the Lewis Foundation.Explaining the team’s findings, lead researcher Dr Michael Scantlebury, from the School of Biological Sciences at Queen’s University Belfast, said: “The more we understand, about the physiology and the hunting tactics of this charismatic animal, the more we are able to ensure its continuing existence.””Our study found that whilst cheetahs are capable of running at exceptionally high speeds, the common adage that they simply ‘outrun’ their prey does not explain how they are able to capture more agile animals. Previous research has highlighted their incredible speed and acceleration and their ability to turn after escaping prey. We have now shown that hunt tactics are prey-specific.”In other words, we now know that rather than a simple maximum speed chase, cheetahs first accelerate towards their quarry before slowing down to mirror prey-specific escaping tactics. We suggest that cheetahs modulate their hunting speed to enable rapid turns, in a predator-prey arms race, where pace is pitted against agility. Basically, cheetahs have clear different chase strategies depending on prey species.”The research suggests that cheetah chases comprise two primary phases, the first an initial rapid acceleration resulting in high speed to quickly catch up with prey, followed by a second, which is a prey-specific slowing period, five to eight seconds before the end of the chase, that enables the cheetah to match turns instigated by prey as the distance between them closes.Dr Scantlebury added: “We have discovered that cheetahs first accelerate rapidly to get them close to the prey but then have to actively slow down to be able to match prey escape manoeuvres. It is like a deadly tango between the hunter and the hunted, with one mirroring the escape tactics of the other.””The time spent in the initial and second phase differs according to prey species, with some species such as ostriches, hares and steenbok attempting to escape by executing sudden changes in direction, whilst other species such as wildebeest, gemsbok and springbok attempt to run fast in a more or less straight line. It almost seems as if the amount of power or effort put into a chase is decided at the beginning of the chase depending on the prey species.”Dr Gus Mills, from the Lewis Foundation, South Africa and Oxford University’s WildCRU said: “Modern technology has given us the opportunity to record and measure facets of animal behaviour we have never been able to do. However, too often this is used without the essential backup of simultaneously observing the animals in the wild to validate what is being measured. …

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