In the world of quantum science, Alice and Bob have been talking to one another for years. Charlie joined the conversation a few years ago, but now with spacelike separation, scientists have measured that their communication occurs faster than the speed of light.For the first time, physicists at the Institute for Quantum Computing (IQC) at the University of Waterloo have demonstrated the distribution of three entangled photons at three different locations (Alice, Bob and Charlie) several hundreds of metres apart, proving quantum nonlocality for more than two entangled photons.The findings of the experiment, Experimental Three-Particle Quantum Nonlocality under Strict Locality Conditions, are published in Nature Photonics today.Once described by Einstein as “spooky action at a distance,” this three-photon entanglement leads to interesting possibilities for multi-party quantum communication.Nonlocality describes the ability of particles to instantaneously know about each other’s state, even when separated by large distances. In the quantum world, this means it might be possible to transfer information instantaneously — faster than the speed of light. This contravenes what Einstein called the “principle of local action,” the rule that distant objects cannot have direct influence on one another, and that an object is directly influenced only by its immediate surroundings.To truly test that the hidden local variables are not responsible for the correlation between the three photons, IQC scientists needed the experiment to close what is known as the locality loophole. They achieved this separation of the entangled photons in a way that did not allow for a signal to coordinate the behaviour of the photons, but beaming the entangled photons to trailers parked in fields several hundred meters from their lab.”Correlations measured from quantum systems can tell us a lot about nature at the most fundamental level,” said co-author Professor Kevin Resch, Canada Research Chair in Optical Quantum Technologies and recent winner of the E.W.R. Steacie Fellowship from the Natural Sciences and Engineering Research Council of Canada (NSERC). “Three-particle entanglement is more complex than that of pairs. We can exploit the complex behaviour to rule out certain descriptions of nature or as a resource for new quantum technologies.”The project team studied the correlations of three photons in a Greenberger-Horne-Zeilinger (GHZ) state — a type of entangled quantum state involving at least three particles.First, photon triplets were generated in Resch’s lab — the Alice in the experiment. Then, the first photon was delayed in a 580m optical fibre in the lab while the two other photons travelled up 85m of optical fibre to the rooftop where they were sent through two telescopes. Both photons were then sent to two trailers, Bob and Charlie, about 700m away from the source and from each other.To maintain the spacelike separate in the experiment, a fourth party, Randy, located in a third trailer randomly selected each of the measurements that Alice was to perform on her photons in the lab.Each trailer contained detectors, time-tagging devices developed by IQC spin off company Universal Quantum Devices (UQD), and quantum random number generators. …Read more
Astronomers for the first time have peered into the heart of an exploding star in the final minutes of its existence.The feat is one of the primary goals of NASA’s NuSTAR mission, launched in June 2012 to measure high-energy X-ray emissions from exploding stars, or supernovae, and black holes, including the massive black hole at the center of our Milky Way Galaxy.The NuSTAR team reported in this week’s issue of the journal Nature the first map of titanium thrown out from the core of a star that exploded in 1671. That explosion produced the beautiful supernova remnant known as Cassiopeia A (Cas A).The well-known supernova remnant has been photographed by many optical, infrared and X-ray telescopes in the past, but these revealed only how the star’s debris collided in a shock wave with the surrounding gas and dust and heated it up. NuSTAR has produced the first map of high-energy X-ray emissions from material created in the actual core of the exploding star: the radioactive isotope titanium-44, which was produced in the star’s core as it collapsed to a neutron star or black hole. The energy released in the core collapse supernova blew off the star’s outer layers, and the debris from this explosion has been expanding outward ever since at 5,000 kilometers per second.”This has been a holy grail observation for high energy astrophysics for decades,” said coauthor and NuSTAR investigator Steven Boggs, UC Berkeley professor and chair of physics. “For the first time we are able to image the radioactive emission in a supernova remnant, which lets us probe the fundamental physics of the nuclear explosion at the heart of the supernova like we have never been able to do before.””Supernovae produce and eject into the cosmos most of the elements are important to life as we know it,” said UC Berkeley professor of astronomy Alex Filippenko, who was not part of the NuSTAR team. “These results are exciting because for the first time we are getting information about the innards of these explosions, where the elements are actually produced.”Boggs says that the information will help astronomers build three-dimensional computer models of exploding stars, and eventually understand some of the mysterious characteristics of supernovae, such as jets of material ejected by some. Previous observations of Cas A by the Chandra X-ray telescope, for example, showed jets of silicon emerging from the star.”Stars are spherical balls of gas, and so you might think that when they end their lives and explode, that explosion would look like a uniform ball expanding out with great power,” said Fiona Harrison, the principal investigator of NuSTAR at the California Institute of Technology. “Our new results show how the explosion’s heart, or engine, is distorted, possibly because the inner regions literally slosh around before detonating.”Expanding supernova remnantCas A is about 11,000 light years from Earth and the most studied nearby supernova remnant. In the 343 years since the star exploded, the debris from the explosion has expanded to about 10 light years across, essentially magnifying the pattern of the explosion so that it can be seen from Earth.Earlier observations of the shock-heated iron in the debris cloud led some astronomers to think that the explosion was symmetric, that is, equally powerful in all directions. Boggs noted, however, that the origins of the iron are so unclear that its distribution may not reflect the explosion pattern from the core.”We don’t know whether the iron was produced in the supernova explosion, whether it was part of the star when it originally formed, if it is just in the surrounding material, or even if the iron we see represents the actual distribution of iron itself, because we wouldn’t see it if it were not heated in the shock,” he said.The new map of titanium-44, which does not match the distribution of iron in the remnant, strongly suggests that there is cold iron in the interior that Chandra does not see. …Read more
A new star is formed by gravitational contraction of an interstellar molecular cloud consisting of gas and dust. In the course of this process, a gas disk (protoplanetary disk), whose size is on the order of 100 AU, forms around the protostar and evolves into a planetary system. The Solar System was also formed in this way about 4.6 billion years ago, and life was eventually born on Earth. How unique in the Universe is the situation which happened for the Solar System? In order to answer this question, understanding the formation of protoplanetary disks as well as the associated chemical evolution in various star forming regions is essential. There have been extensive observational efforts made towards this goal. Until now, most of them have focused on changes in the physical structure and the kinematics during the formation process. However, it was very difficult to distinguish the protoplanetary disk from the infalling envelope clearly with such conventional approaches.The chemical evolution associated with disk formation has scarcely been studied observationally because of the insufficient sensitivity and spatial resolution of previous radio telescopes. As a result, a chemical model calculation with many assumptions is the only approach. Naturally, the physical and chemical changes in the disk formation should be coupled with each other. …Read more
The abundance of crop pests in developing countries may be greatly underestimated, posing a significant threat to some of the world’s most important food producing nations, according to research led by the University of Exeter.Data on the known distributions of almost 2,000 crop-destroying organisms in 195 countries were analyzed in the first global assessment of the factors determining the distribution of crop pests.Dr Dan Bebber and Professor Sarah Gurr, of Biosciences at the University of Exeter, found that if all countries had levels of scientific and technical capacity similar to the developed world, the number of pests reported would rise greatly and the true extent of the threat would be better understood.Many developing countries are expected to harbor hundreds of unreported crop pests and diseases, based on current levels of agricultural productivity.Around one sixth of the world’s agricultural production is lost to destructive organisms annually, with further losses post-harvest.Crop pests are often introduced by human activities such as trade and travel, with the wealth of a country linked to the number of invasive species recorded there because — whilst growing rich through trade — they have also accidentally imported pests in agricultural produce.But this study also considered the link between the wealth of a country (by per capita GDP) and its ability to detect, identify and report the number of crop pests present.Developing countries are less likely to have the capacity to observe invasive species than affluent, technologically-advanced nations.The researchers used data collated from published literature over many decades by the inter-governmental, not-for-profit organization CABI and made available from its Plantwise knowledge bank.Using GDP and scientific output as indicators of pest detection capacity, the study found that the pest load of the developing world appears to be greatly underestimated, and that this lack of knowledge may be severely hampering crop protection in some of the world’s most important food producing nations.Dr Dan Bebber said: “Crop pests pose a significant and growing threat to food security, but their geographical distributions are poorly understood.””Country wealth is likely to be a strong indicator of observational capacity, not just trade flow, as has been interpreted in previous studies of invasive species. If every country had US-levels of per capita GDP, then on average countries woul d be reporting more than 200 additional pests and diseases. This suggests that enhanced investment in pest observations will reveal the hidden threat of crop pests and pathogens, as well as bring into focus the opportunity to lose less of the crop by appropriate pest control. The first step to solving crop losses is to identify the pests responsible.”The largest numbers of crop pests were reported by the USA, followed by India, China, France and Japan. Island nations reported more pests than coastal and landlocked nations, and the number of pests increased slightly with rainfall.Professor Sarah Gurr added: “This follows hot on the heels of our recent paper showing that pests and pathogens are on the move in the face of climate change. When coupled to this study we can see that many nations are underestimating pest and pathogen loads. Taken collectively, these papers draw attention not only to the threat of crop disease, and thus global food security, but also to our need for more trained pathologists to inform policy.”Story Source:The above story is based on materials provided by University of Exeter. Note: Materials may be edited for content and length.Read more
TheAustralian Asbestos Diseases Research Institute (ADRI)has announced aclinical trialfora newly developed drug therapy in the treatment of mesothelioma.Researchers at the ADRI conducted a three year study focused on the genetic characteristics and the gene expression and found that a particular family of microRNAs was greatly decreased in mesothelioma.MicroRNAs are small genes involved in the regulation of cell and tumor biology, inhibition of this particular type of microRNAs is commonly found in other types of cancers but has never been linked to mesothelioma.Researchers treated human derived mesothelioma tumors in mice with a synthetic version of microRNA, the drug TargomiRs, in an attempt to bring the microRNA levels back up to normal. The drug was administered by way of minicells, a new drug delivery system developed …Read more
Oct. 17, 2013 — In collaboration with international colleagues, a research group at Aarhus University has contributed to the compilation of the most comprehensive botanical data set to date. PhD student Naia Morueta-Holme and her supervisor, Professor Jens-Christian Svenning, Department of Bioscience, spearheaded the analysis that reveals where rare species are found in the New World (North and South America) and the factors that determine whether a region is dominated by widespread or rare species.”The study shows that especially California, Mexico, the Caribbean islands, parts of the Andes, the south of South America, and the region around Rio de Janeiro are dominated by rare species. This came as a surprise to us, because the regions are very different in terms of climate and vegetation type. They include habitats such as wet tropical rainforests, dry subtropical regions, and even deserts, tropical mountains, and cool temperate grasslands and forests,” says Professor Svenning.However, the studies show that consistent processes are driving the distribution of the plants.”There are two factors in particular that are important for the distribution of the rare species. Firstly, a stable climate with relatively small seasonal differences, where the climate has remained much the same for tens of thousands of years. Secondly, only small areas of habitat are involved. The species are unable to spread, but the stability nevertheless enables them to survive for long periods of time, and to develop and specialise in the same place,” explains Naia Morueta-Holme.In large areas in the north of North America, on the other hand, the seasons vary significantly, and there have been distinct climate changes between ice ages (glacials) and warm ages (interglacials). Widespread species are dominant here, either because they can withstand a wide range of climate conditions or because they are good at dispersing and can track changes in climate over time. They can thus spread over the large habitat areas available.Rare species threatened by climate changeIn terms of the dominance of rare species, the close link between the size of the habitat area and a stable climate is of great concern regarding the impact of human-induced climate changes now prevailing in these regions.”Even though we’re expecting less climate change in the areas dominated by rare species than in North America, for example, it could well be that future changes may be beyond what the species can tolerate. …Read more
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. …Read more
Sep. 10, 2013 — New research has revealed the hidden past of crocodiles, showing for the first time how these fierce reptiles evolved and survived in a dinosaur dominated world.While most modern crocodiles live in freshwater habitats and feed on mammals and fish, their ancient relatives were extremely diverse — with some built for running around like dogs on land and others adapting to life in the open ocean, imitating the feeding behaviour of today’s killer whales.Research published today [11 September] in the journal Proceedings of the Royal Society B shows, for the first time, how the jaws of ancient crocodiles evolved to enable these animals to survive in vastly different environments, all whilst living alongside the dinosaurs 235 to 65 million years ago.The study was conducted by Tom Stubbs and Dr Emily Rayfield from the University of Bristol, together with Dr Stephanie Pierce from The Royal Veterinary College and Dr Phil Anderson from Duke University.Tom Stubbs, who led the research at the University of Bristol, said: “The ancestors of today’s crocodiles have a fascinating history that is relatively unknown compared to their dinosaur counterparts. They were very different creatures to the ones we are familiar with today, much more diverse and, as this research shows, their ability to adapt was quite remarkable.”Their evolution and anatomical variation during the Mesozoic Era was exceptional. They evolved lifestyles and feeding ecologies unlike anything seen today.”The research team examined variation in the morphology (shape) and biomechanics (function) of the lower jaws in over 100 ancient crocodiles, using a unique combination of numerical methods.Dr Stephanie Pierce, from The Royal Veterinary College, said: “We were curious how extinction events and adaptations to extreme environments during the Mesozoic — a period covering over 170 million years — impacted the feeding systems of ancient crocodiles and to do this we focused our efforts on the main food processing bone, the lower jaw.”By analysing variation in the lower jaw, the researchers provide novel insights into how the feeding systems of ancient crocodiles evolved as the group recovered from the devastating end-Triassic extinction event and subsequently responded to the distribution of ecological resources, such as habitat and foodstuff.For the first time, the research has shown that, following the end-Triassic extinction, ancient crocodiles invaded the Jurassic seas and evolved jaws built primarily for hydrodynamic efficiency to capture agile prey, such as fish. However, only a small range of elongate lower jaw shapes were suitable in Jurassic marine environments.The study has also revealed that variation peaked again in the Cretaceous, where ancient crocodiles evolved a great variety of lower jaw shapes, as they adapted to a diverse range of feeding ecologies and terrestrial environments, alongside the dinosaurs.Surprisingly, the lower jaws of Cretaceous crocodiles did not have a great amount of biomechanical variation and, instead, the fossil record points towards novel adaptations in other areas of their anatomy, such as armadillo-like body armour.Dr Pierce added: “Our results show that the ability to exploit a variety of different food resources and habitats, by evolving many different jaw shapes, was crucial to recovering from the end-Triassic extinction and most likely contributed to the success of Mesozoic crocodiles living in the shadow of the dinosaurs.”This exceptional variation has never before been explored numerically, with no studies ever having incorporated such a wide range of crocodiles over such a long time period.Read more
Aug. 29, 2013 — Biologists at Ludwig-Maximilians-Universitaet (LMU) in Munich have demonstrated that people can acquire the capacity for echolocation, although it does take time and work.As blind people can testify, we humans can hear more than one might think. The blind learn to navigate using as guides the echoes of sounds they themselves make. This enables them to sense the locations of walls and corners, for instance: by tapping the ground with a stick or making clicking sounds with the tongue, and analyzing the echoes reflected from nearby surfaces, a blind person can map the relative positions of objects in the vicinity. LMU biologists led by Professor Lutz Wiegrebe of the Department of Neurobiology (Faculty of Biology) have now shown that sighted people can also learn to echolocate objects in space, as they report in the biology journal Proceedings of the Royal Society B.Wiegrebe and his team have developed a method for training people in the art of echolocation. With the help of a headset consisting of a microphone and a pair of earphones, experimental subjects can generate patterns of echoes that simulate acoustic reflections in a virtual space: the participants emit vocal clicks, which are picked up by the microphone and passed to a processor that calculates the echoes of a virtual space within milliseconds. The resulting echoes are then played back through the earphones. The trick is that the transformation applied to the input depends on the subject’s position in virtual space. So the subject can learn to associate the artificial “echoes” with the distribution of sound-reflecting surfaces in the simulated space.A dormant skill”After several weeks of training, the participants in the experiment were able to locate the sources of echoes pretty well. This shows that anyone can learn to analyze the echoes of acoustic signals to obtain information about the space around him. …Read more
Aug. 27, 2013 — Two treatments that slow the development of diabetes also may protect people from heart disease, according to a recent study accepted for publication in The Endocrine Society’s Journal of Clinical Endocrinology & Metabolism (JCEM).Researchers examined the effect that making intensive lifestyle changes or taking the medication metformin had on cholesterol and triglyceride levels. The study, part of the National Institutes of Health’s Diabetes Prevention Program, found that both treatments induced positive changes in the level of particles that carry cholesterol and triglycerides through the blood stream. These changes could lower the chances of plaque building up in blood vessels.”Cardiovascular disease is the most significant cause of death and disability in people with diabetes,” said the study’s lead author, Ronald Goldberg, MD, of the University of Miami’s Miller School of Medicine. “Our findings demonstrate that the same therapies used to slow the onset of diabetes also may help allay the risk of heart disease.”The randomized clinical trial analyzed blood samples from 1,645 people with impaired glucose tolerance. Participants were randomly assigned to one of three groups — one taking the medication metformin, another taking a placebo and a third undergoing an intensive lifestyle modification program. Researchers compared baseline blood samples from the start of the study to samples taken a year later to measure the interventions’ effects. The study used advanced techniques to obtain a detailed picture of the various particles in the blood.People who took part in the lifestyle modification program had lower levels of triglycerides and the particles that carry this kind of fat in the blood after a year. Both the metformin and lifestyle interventions were linked to reductions in the number of small low-density lipoprotein (LDL) particles, which carry cholesterol that may contribute to plaque formation, and increases in high-density lipoproteins (HDL), the form of cholesterol that reduces heart disease risk.”Preventing or slowing the development of diabetes with these treatments also improves the cholesterol and triglyceride profile of a person’s blood,” Goldberg said. “Thanks to the added benefits of existing diabetes interventions, we stand a better chance of lowering the risk of heart disease in this patient population.”Other researchers working on the study include: M. …Read more
June 20, 2013 — The protected area network in Tanzania is playing a vital role in the survival of savannah bird species as they move west in response to climate and environmental changes, according to new research led by the University of York.Using data on savannah birds from the Tanzanian Bird Atlas project — which has documented Tanzanian bird distributions over recent decades — the researchers found that they are using protected areas as stepping stones as they move to areas further west where dry seasons are getting longer, with movements of up to 300km noted.Much debate has centred on the effectiveness of the current protected area network to protect biodiversity in the face of climate and environmental changes.However, the new study, which is published in Ecology Letters, not only provides the first evidence of climate-driven shifts for an African bird community, but suggests that continued maintenance of existing protected areas — which include national parks and game reserves — remains an appropriate response to the challenge of climate and environmental changes.Lead author Dr Colin Beale, from York’s Department of Biology, said: “Although the protected area network was set up for mammals, our research shows it is assisting dry bush species of birds to respond to land degradation, caused by over-grazing, conversion to crops and the loss of trees, as well as climate change.”We discovered that rather than declining in value as birds move in response to climate changes, protected areas in Tanzania are becoming increasingly valuable as land degradation exerts pressures elsewhere. Our research suggests that protected areas are buffering the bird community against extinction due to land degradation and offer stepping stones for species that are altering their distribution in response to climate change.”The study, which also involved researchers from Queens University Belfast and Biomathematics and Statistics Scotland, compared data for 139 Tanzanian savannah bird species, such as hornbills, francolins, the Rufous-tailed Weaver, Fischer’s Sparrowlark and the Pangani Longclaw. Data from 1960 to 1989 was compared to data post 2000.Unlike previous assessments of the efficiency of the protected area network in the face of climate change, the new study is based on observed changes rather than modelling.Neil Baker, from Tanzania Bird Atlas, said: “This study once again emphasises the value of the long term collection of reliable, meaningful data and the vital role of the citizen scientist. Indeed, with so few professionals in the Afrotropics this is the only way to collect this information. With the accuracy of satellite derived variables improving and with widespread use of hand held GPS units, georeferenced observations will allow even more accurate assessments of population movements in the near future.”Read more
June 19, 2013 — Oscar Wilde called memory “the diary that we all carry about with us.” Now a team of scientists has developed a way to see where and how that diary is written.Led by Don Arnold and Richard Roberts of USC, the team engineered microscopic probes that light up synapses in a living neuron in real time by attaching fluorescent markers onto synaptic proteins — all without affecting the neuron’s ability to function.The fluorescent markers allow scientists to see live excitatory and inhibitory synapses for the first time and, importantly, how they change as new memories are formed.The synapses appear as bright spots along dendrites (the branches of a neuron that transmit electrochemical signals). As the brain processes new information, those bright spots change, visually indicating how synaptic structures in the brain have been altered by the new data.”When you make a memory or learn something, there’s a physical change in the brain. It turns out that the thing that gets changed is the distribution of synaptic connections,” said Arnold, associate professor of molecular and computational biology at the USC Dornsife College of Letters, Arts and Sciences, and co-corresponding author of an article about the research that appears in Neuron on June 19.The probes behave like antibodies, but they bind more tightly and are optimized to work inside the cell — something that ordinary antibodies can’t do. To make these probes, the team used a technique known as “mRNA display,” which was developed by Roberts and Nobel laureate Jack Szostak.”Using mRNA display, we can search through more than a trillion different potential proteins simultaneously to find the one protein that binds the target the best,” said Roberts, co-corresponding author of the article and professor of chemistry and chemical engineering with joint appointments at USC Dornsife and the USC Viterbi School of Engineering.Arnold and Roberts’ probes (called “FingRs”) are attached to green fluorescent protein (GFP), a protein isolated from jellyfish that fluoresces bright green when exposed to blue light. Because FingRs are proteins, the genes encoding them can be put into brain cells in living animals, causing the cells themselves to manufacture the probes.The design of FingRs also includes a regulation system that cuts off the amount of FingR-GFP that is generated after 100 percent of the target protein is labeled, effectively eliminating background fluorescence — generating a sharper, clearer picture.These probes can be put in the brains of living mice and then imaged through cranial windows using two-photon microscopy.The new research could offer crucial insight for scientists responding to President Barack Obama’s Brain Research Through Advancing Innovative Neurotechnologies (BRAIN) Initiative, which was announced in April.Modeled after the Human Genome Project, the objective of the $100 million initiative is to fast-track research that maps out exactly how the brain works and “better understand how we think, learn and remember,” according to the BRAIN Initiative website.The research was supported by funding from National Institutes of Health (grant numbers GM-083898, MH-086381, GM-083898 and GM-060416).Read more
May 1, 2013 — The researchers, Dr Bellinda Gallardo and Dr David Aldridge from the University of Cambridge, focussed on the ‘dirty dozen’ — a group of high-risk invasive aquatic plants and animals. Some, like the killer shrimp (Dikerogammarus villosus) and the bloody red mysid (Hemimysis anomala) are already in UK but have yet to spread. Others, such as the Asian clam (Corbicula fluminalis) and the marmokrebs, a crayfish (Procambarus fallax) may not yet have arrived.
Working with Species Distribution Models, which are routinely used to predict which regions most suit invasive species, the Cambridge pair made the models more accurate by including human factors such as population density, land-use and proximity to ports. Traditionally, the models are based on environmental conditions such as temperature and rainfall.
According to Dr Gallardo: “Invasive species need to be in the right place at the right time; they need the right environmental conditions, but they also need a helping hand from humans. This can happen intentionally, for example through introduction of commercial fish, or accidentally via hulls of boats, fishing equipment, or ballast water.”
The role of humans, plus invasive species’ great adaptability, make predicting their spread challenging. By including both human and environmental factors in the models, the researchers found the risk of invasion in the UK was increased by 20% in coastal, densely populated areas and places near transport routes, with the Thames, Anglian and Humber river basins at highest risk.
“These river basins already host many aquatic invaders. This is particularly worrying because invasive species often modify their habitat, making it more favourable to other invaders. This can eventually lead to a process known as invasional meltdown,” she says.
Tackling the problem is costly. Invasive species are the second biggest threat to biodiversity after habitat loss. Around 12,000 invasive species have already arrived in Europe, where their combined impact on native biodiversity, agriculture, health and the economy costs at least €12 billion a year.
By producing more accurate maps, the study should allow environmental managers and policy makers to target resources at the most invasive species and the areas most under threat. “Effective management of invasive species depends on rapid detection and control. Our maps are fundamental to direct biomonitoring efforts towards areas most suitable for the ‘dirty dozen’, so they can be detected as soon as possible,” Dr Gallardo explains.
“At present, environmental managers and policy makers have few tools to make informed decisions about the risk posed by existing and future invaders. Our study gives them basic information to prioritise management and control decisions regarding 12 of the most worrisome freshwater invasive species.”
The study is also timely because of climate change, which might further favour invasive species, she adds: “Invasive species might better adapt to climate change than natives because of their wide environmental tolerance and highly competitive biological traits. And because they usually reproduce rapidly, invasive species may be better than native species at resisting and recovering from extreme events.”Read more
May 21, 2013 — Researchers from the University of Hawaii — Manoa (UHM) School of Ocean and Earth Science and Technology (SOEST) developed species distribution models of the six dominant Hawaiian coral species around the main Hawaiian Islands including two species currently under consideration as threatened or endangered.
They found the order of coral abundance (from highest to lowest) around the main Hawaiian Islands to be Porites lobata, Montipora patula, Pocillopora meandrina, Montipora capitata, Porites compressa, and Montipora flabellata.
Environmental factors (wave energy, shape of the seafloor, water clarity, depth, rugosity (roughness of the seafloor), geological island age, and organic sediment content) are known to influence Hawaiian reefs. However, this is the first study to systematically examine the influence of these factors on the distribution and abundance of coral species across the entire seascape of shallow reefs in the main Hawaiian Islands (MHI).
“Average wave height and maximum wave height were the most influential variables explaining coral abundance in the Hawaiian Islands,” reported Erik Franklin, lead author of the study and Assistant Research Professor at the UHM Hawaii Institute of Marine Biology. “Our models also identified relationships between coral cover and island age, depth, sunlight, rugosity, slope, and aspect (direction a slope faces).”
In general, coral cover was predicted to be highest in primarily wave-sheltered coastlines and embayments. Reefs with highest cover were concentrated in Kaneohe Bay on Oahu; the wave-sheltered reefs of Molokai, Lanai, Maui, and Kahoolawe; and the Kohala coast of Hawaii.
To construct the species distribution and abundance models, researchers integrated field surveys for corals (data provided by the US National Park Service and US National Oceanic and Atmospheric Administration) with environmental data of wave exposure (data provided by UHM Department of Ocean and Resources Engineering), benthic geomorphology, and sunlight from 2000 to 2009.
Regional-scale mapping of coral species from these models provide a framework for population modeling and marine spatial planning of Hawaiian coral reefs. The geographic characterization of coral reefs would benefit greatly from the improved coral distribution and abundance information generated from coral distribution models. Data from these models can be incorporated into marine conservation plans or used for threat assessments to reefs.
“For example,” Franklin says, “our results were recently used in the management plan review process of the Hawaiian Islands Humpback Whale National Marine Sanctuary as they considered the distribution and abundance of animals other than whales.”
One advantage of this integrative, modeling approach is that researchers are able to consider a broader range of areas than field surveys alone and, therefore, can provide a truer picture of total abundance. “We were most surprised at the high relative abundance of Montipora patula which is currently under consideration for listing as a threatened or endangered species,” reported Franklin. Montipora flabellata, the other coral species under consideration as a threatened or endangered species, was not as abundant as the other five species.
Franklin and colleagues are in the process of extending the modeling approach to include additional marine species in Hawaii such as reef fish and include additional environmental variables to try to improve the predictive capacity of the models. Ideally the results will continue to inform marine resource management in the Hawaiian Islands.Read more
May 8, 2013 — A comprehensive five-year study by University of Calgary ecologists — which included monitoring the activity of wolves, elk, cattle and humans — indicates that two accepted principles of how ecosystems naturally operate could be overshadowed by the importance of human activity.
“Understanding the significance of the impact that humans have on ecosystems is a critical component in formulating long-term and effective conservation strategies,” says principal investigator Marco Musiani.
“Our results led us to believe that ecologists have underestimated the impact of humans on natural food chains. The data we collected shows that humans are deliberately or inadvertently engineering ecosystems regardless of whether they would be naturally pre-disposed to top-down or bottom-up effects. Even in protected areas, the influence of humans might be greater than we previously thought.”
Ecologists have long debated whether natural ecosystems and associated food chains are primarily regulated by predators or by the productivity of plant species, called top-down and bottom-up effects, respectively. With most of the world’s ecosystems now dominated by humans, researchers from the University of Calgary sought to understand how much people influenced food chains in southwest Alberta.
Lead author Tyler Muhly, PhD, said the study — a collaboration between NSERC, Shell Canada, Parks Canada, the Alberta Government and the Universities of Alberta, Calgary and Montana — relied upon dozens of high-tech animal tagging devices and motion sensor-activated cameras to study human, animal and plant distribution throughout southwest Alberta. The research area stretched from Calgary in the northeast, through to the provincial borders with British Columbia in the west and the US-Canada border in the south. “We painstakingly monitored wolves, elk, cattle and plant species, as well as humans for five years. We evaluated how these species interacted across the landscape and ultimately found that humans dominated the ecosystem,” Muhly says.
“In particular, we found that forage-mediated effects of humans (bottom-up effects) were more influential than predator-mediated effects in the food chain. The presence of humans was most correlated with occurrence of forage (plants). Elk and cattle distribution correlated closely with forage, and the distribution of wolves matched that of the elk and cattle they view as potential prey.
“Our results contrast with research conducted in protected areas that suggested food chains are primarily regulated by predators. Rather, we found that humans influenced other species in the food chain in a number of direct and indirect ways, thus overshadowing top-down and bottom-up effects,” Muhly says.Read more