Researchers work to save endangered New England cottontail

Scientists with the NH Agricultural Experiment Station are working to restore New Hampshire and Maine’s only native rabbit after new research based on genetic monitoring has found that in the last decade, cottontail populations in northern New England have become more isolated and seen a 50 percent contraction of their range.The endangered New England cottontail is now is at risk of becoming extinct in the region, according to NH Agricultural Experiment Station researchers at the University of New Hampshire College of Life Sciences and Agriculture who believe that restoring habitats is the key to saving the species.”The New England cottontail is a species of great conservation concern in the Northeast. This is our only native rabbit and is an integral component of the native New England wildlife. Maintaining biodiversity gives resilience to our landscape and ecosystems,” said NHAES researcher Adrienne Kovach, research associate professor of natural resources at UNH.New England cottontails have been declining for decades. However, NHAES researchers have found that in the last decade, the New England cottontail population in New Hampshire and Maine has contracted by 50 percent; a decade ago, cottontails were found as far north as Cumberland, Maine.The majority of research on New England cottontails has come out of UNH, much of it under the leadership of John Litvaitis, professor of wildlife ecology, who has studied the New England cottontail for three decades. Kovach’s research expands on this knowledge by using DNA analysis to provide new information on the cottontail’s status, distribution, genetic diversity, and dispersal ecology.The greatest threat and cause of the decline of the New England cottontail is the reduction and fragmentation of their habitat, Kovach said. Fragmentation of habitats occurs when the cottontail’s habitat is reduced or eliminated due to the maturing of forests or land development. Habitats also can become fragmented by roads or natural landscape features, such as bodies of water.”Cottontails require thicketed habitats, which progress from old fields to young forests. Once you have a more mature forest, the cottontail habitat is reduced. A lot of other species rely on these thicket habitats, including bobcats, birds, and reptiles. Many thicket-dependent species are on decline, and the New England cottontail is a representative species for this kind of habitat and its conservation,” Kovach said.Kovach explained that for cottontail and most animal populations to be healthy and grow, it is important for adult animals to leave the place where they were born and relocate to a new habitat, which is known as dispersal. …

Read more

Students on field course bag new spider species

As a spin-off (pun intended) of their Tropical Biodiversity course in Malaysian Borneo, a team of biology students discover a new spider species, build a makeshift taxonomy lab, write a joint publication and send it off to a major taxonomic journal.Discovering a new spider species was not what she had anticipated when she signed up for her field course in Tropical Biodiversity, says Elisa Panjang, a Malaysian master’s student from Universiti Malaysia Sabah. She is one of twenty students following the course, organised by Naturalis Biodiversity Center in The Netherlands, and held in the Danau Girang Field Centre in Sabah, Malaysian Borneo. The aim of the one-month course, say organisers Vincent Merckx and Menno Schilthuizen, is to teach the students about how the rich tapestry of the tropical lowland rainforest’s ecosystem is woven.Besides charismatic species, such as the orangutans that the students encounter every day in the forest, the tropical ecosystem consists of scores of unseen organisms, and the course focus is on these “small things that run the world” — such as the tiny orb-weaving spiders of the tongue-twistingly named family Symphytognathidae. These one-millimetre-long spiders build tiny webs that they suspend between dead leaves on the forest floor. “When we started putting our noses to the ground we saw them everywhere,” says Danish student Jennie Burmester enthusiastically. What they weren’t prepared for was that the webs turned out to be the work of an unknown species, as spider specialist Jeremy Miller, an instructor on the course, quickly confirmed.The students then decided to make the official naming and description of the species a course project. They rigged the field centre’s microscopes with smartphones to produce images of the tiny spider’s even tinier genitals (using cooking oil from the station’s kitchen to make them more translucent), dusted the spider’s webs with puffs of corn flour (also from the kitchen) to make them stand out and described the way they were built. They also put a spider in alcohol as “holotype,” the obligatory reference specimen for the naming of any new species — which is to be stored in the collection of Universiti Malaysia Sabah. Finally, a dinner-time discussion yielded a name for this latest addition to the tree of life: Crassignatha danaugirangensis, after the field centre’s idyllic setting at the Danau Girang oxbow lake.All data and images were then compiled into a scientific paper, which, via the station’s satellite link, was submitted to the Biodiversity Data Journal, a leading online journal for quick dissemination of new biodiversity data. Even though thousands of similarly-sized spider species still await discovery, Miller thinks the publication is an important one. …

Read more

Temperature and ecology: Rival Chilean barnacles keep competition cool

Here are two facts that make the lowly barnacle important: They are popular models for ecology research, and they are very sensitive to temperature. Given that, the authors of a new study about a bellwether community of two barnacle species in Chile figured they might see clear effects on competition between these two species if they experimentally changed temperature. In the context of climate change, such an experiment could yield profound new insights into the biological future of a major coastline that is prized for its ecological, aesthetic, and economic values.But in the study to be printed in the April 2014 issue of the Journal of Experimental Marine Biology and Ecology, the scientists found no significant effect of temperature on competition at all. That surprising non-finding may have its own implications.”The dominant if somewhat dated narrative in marine ecology, and ecology more broadly, is that competition is a major structuring force in natural communities,” said co-author Heather Leslie, assistant professor of environmental studies and biology at Brown University. “We know it’s a more nuanced story, but to find cases where it’s a bit of a draw is really unusual.”Moreover, temperature did not turn out to be the mediating factor.”Temperature wasn’t the beast that we often think of it being, which in itself is surprising,” Leslie said.Plenty of studies of other co-occurring barnacles would have suggested otherwise. In the North Atlantic, there is a well-documented and clear dynamic between two barnacle species, the little gray barnacle (Chthamalus fragilis) and the northern rock barnacle (Semibalanus balanoides). The little gray barnacle can only survive high up on the rocks, where it is hottest and driest, because farther down it gets thoroughly routed by the northern rock barnacle. Temperature, in other words, provides the little gray’s only refuge.The picture in Chile was downright unclear. Previous studies had yielded conflicting hints about how temperature might affect the competition between two southern hemisphere barnacle species, Jehlius cirratus and Notochthalamus scabrosus. Led by Emily Lamb, who began the work as a Brown undergraduate concentrating in environmental science and is now a research assistant at the Estacin Costera de Investigaciones Marinas (ECIM) in Chile, the team devised an experiment to get a more definitive answer.Made in the shadeLike their northern cousins, the Chilean barnacles Jehlius and Notochthalamus live in a clearly stratified society with Jehlius more abundant higher up and Notochthalamus more abundant lower down into the tide. …

Read more

Zebrafish discovery may shed light on human kidney function

Researchers say the discovery of how sodium ions pass through the gill of a zebrafish may be a clue to understanding a key function in the human kidney. The findings from a collaboration between Mayo Clinic and the Tokyo Institute of Technology appear in the online issue of the American Journal of Physiology-Regulatory, Integrative and Comparative Physiology.The researchers discovered a protein responsible for gas exchanges in the fish gill structure. Specifically they studied and characterized the Na+/H+ (sodium/hydrogen) exchanger named NHE3, responsible for controlling sodium and hydrogen ions across the gill. The researchers also directly demonstrated that NHE3 can function as a Na+/NH4+ (sodium/ammonium) exchanger.”This is significant because the fish tends to mimic the process in humans,” says Michael Romero, Ph.D., a Mayo Clinic physiologist who works in nephrology. “This is the true beauty of comparative physiology– a lot of the organs function by very similar processes, down to ionic transfer.”In this case the protein allows the sodium ions to be absorbed from the forming urine while at the same time discarding waste from normally functioning cells, thus keeping the body in balance and serving as an energy saving system. The researchers say the same NHE3 protein performs a similar function in the intestine, pancreas, liver, lungs and reproductive system.The gill is used in the fish as a transport system: sodium ions are nutrients and ammonium carries away waste. It’s a key process allowing zebrafish to extract sodium ions from fresh water. In humans, NHE3 is involved in the acid-waste control system in the kidney, but there hasn’t been a good analysis of that process in humans. Part of this acid-control process in the human kidney is “ammoniagenesis” which requires the initial part of the kidney tubule (proximal tubule) to export ammonia/ammonium. Physiologically, it has been assumed that NHE3 can perform a Na+/NH4+ exchange, but this has never been experimentally demonstrated.Ammoniagenesis and increased renal sodium bicarbonate absorption are partly under the control of the renin-angiotensin-aldosterone system (RAAS), which means that this work enhances understanding of human hypertension. …

Read more

Extreme weather caused by climate change decides distribution of insects, study shows

As climate change is progressing, the temperature of our planet increases. This is particularly important for the large group of animals that are cold-blooded (ectothermic), including insects. Their body temperature is ultimately determined by the ambient temperature, and the same therefore applies to the speed and efficiency of their vital biological processes.But is it changes in average temperature or frequency of extreme temperature conditions that have the greatest impact on species distribution? This was the questions that a group of Danish and Australian researchers decided to examine in a number of insect species.Johannes Overgaard, Department of Bioscience, Aarhus University, Denmark, Michael R. Kearney and Ary A. Hoffmann, Melbourne University, Australia, recently published the results of these studies in the journal Global Change Biology. The results demonstrate that it is especially the extreme temperature events that define the distribution of both tropical and temperate species. Thus climate change affects ectotermic animals primarily because more periods of extreme weather are expected in the future.Fruit flies were modeledThe researchers examined 10 fruit fly species of the genus Drosophila adapted to tropical and temperate regions of Australia. First they examined the temperatures for which the species can sustain growth and reproduction, and then they found the boundaries of tolerance for hot and cold temperatures.”This is the first time ever where we have been able to compare the effects of extremes and changes in average conditions in a rigorous manner across a group of species,” mentions Ary Hoffmann.Based on this knowledge and knowledge of the present distribution of the 10 species they then examined if distribution was correlated to the temperatures required for growth and reproduction or rather limited by their tolerance to extreme temperature conditions.”The answer was unambiguous: it is the species’ tolerance to very cold or hot days that define their present distribution,” says Johannes Overgaard.It is therefore the extreme weather events, such as heat waves or extremely cold conditions, which costs the insects their life, not an increase in average temperature.Drastic changes in storeWith this information in hand, the researchers could then model how distributions are expected to change if climate change continues for the next 100 years.Most terrestrial animals experience temperature variation on both daily and seasonal time scale, and they are adapted to these conditions. Thus, for a species to maintain its existence under varying temperature conditions there are two simple conditions that must be met. …

Read more

Poaching threatens savannah ecosystems

White rhinoceros may be extinct in twenty years with the current poaching rates. The loss of this megaherbivore is in itself a tragedy, but it may also have tremendous effects on the ecosystems they now live in.The white rhino (Ceratotherium simum), and other megaherbivores, are key drivers of ecosystem functioning because theyre not controlled by predation.A new study by Joris Cromsigt and Mariska te Beest, published in Journal of Ecology, highlights the role of the white rhino in the savannah ecosystems.Earlier empirical studies on the ecosystem impact of megaherbivores are strongly biased to African elephant with very little contemporary evidence for other megaherbivore species. Cromsigt and te Beest quantifies how rhino recolonized Kruger National Park (KNP) following their re-introduction in the 1960s to create a unique ‘recolonization experiment’ and tests how this megagrazer is affecting the structure of savannah grasslands.The researchers identified landscapes that rhino recolonized long time ago versus landscapes that were recolonized more recently. The assumption was that time since colonization represents a proxy for extent of rhino impact. Grassland heterogeneity on 40 transects covering a total of 30 kilometer were recorded. Short grass cover was clearly higher in the high rhino impact than low rhino impact landscape. Moreover, they encountered about 20 times more grazing lawns, a specific grassland community, in the high rhino impact landscape. The conclusion is that white rhinoceros may have started to change the structure and composition of KNP’s savannah grasslands. The amount of short grass has important consequences for other species, but also components of ecosystem functioning such as fire regimes. The results highlight that this poaching crisis not only affects the species but threatens the potentially key role of this megaherbivore as a driver of savannah functioning.Story Source:The above story is based on materials provided by Swedish University of Agricultural Sciences (SLU). …

Read more

Fish living near the equator will not thrive in the warmer oceans of the future

According to an international team of researchers, the rapid pace of climate change is threatening the future presence of fish near the equator.”Our studies found that one species of fish could not even survive in water just three degrees Celsius warmer than what it lives in now,” says the lead author of the study, Dr Jodie Rummer from the ARC Centre of Excellence for Coral Reef Studies (Coral CoE) at James Cook University.Dr Rummer and her colleagues studied six common species of fish living on coral reefs near the equator. She says many species in this region only experience a very narrow range of temperatures over their entire lives, and so are likely adapted to perform best at those temperatures.This means climate change places equatorial marine species most at risk, as oceans are projected to warm by two to three degrees Celsius by the end of this century.”Such an increase in warming leads to a loss of performance,” Dr Rummer explains. “Already, we found four species of fish are living at or above the temperatures at which they function best.”The team measured the rates at which fish use oxygen, the fuel for metabolism, across different temperatures — at rest and during maximal performance. According to the results, at warmer temperatures fish lose scope for performance. In the wild, this would limit activities crucial to survival, such as evading predators, finding food, and generating sufficient energy to breed.Because many of Earth’s equatorial populations are now living close to their thermal limits, there are dire consequences ahead if these fish cannot adapt to the pace at which oceans are warming.Dr Rummer suggests there will be declines in fish populations as species may move away from the equator to find refuge in areas with more forgiving temperatures.”This will have a substantial impact on the human societies that depend on these fish,” she says.A concentration of developing countries lies in the equatorial zone, where fish are crucial to the livelihoods and survival of millions of people, including those in Papua New Guinea and Indonesia.In an era of rapid climate change, understanding the link between an organism and its environment is crucial to developing management strategies for the conservation of marine biodiversity and the sustainable use of marine fisheries.”This is particularly urgent when considering food security for human communities.”Story Source:The above story is based on materials provided by ARC Centre of Excellence in Coral Reef Studies. Note: Materials may be edited for content and length.

Read more

Eucalypt in Ethiopian highlands: Increasing productivity of important tree

Researchers at the UPM are collaborating in a eucalypts breeding program in the Ethiopian highlands which will increase this species productivity.This program is developed by the research group of Forest Physiology and Genetics and the cooperative group of Support to Forestry Development of the Universidad Politcnica de Madrid (UPM). Also, it is supported by several national and international institutions that will contribute to satisfy the demand of woody biomass and other financial needs of Ethiopian farmers.For years, these two research groups have been collaborating with Forestry Research Center and the St. Mary’s College and supported by Ence and the Council of Alcorcn. Also, they are working on providing the Ethiopian highlands with tools and knowledge for better forestry management. This could constitute a valuable tool to achieve sustainability when using and supplying natural resources. The main project consists of a eucalypt breeding program that will result in improvements in many areas.The great demand for forest products to use for agriculture by the population of the Ethiopian highlands has resulted in the deforestation of a region with the lowest human development rate in the world. The eucalypt is the species with the highest demand among Ethiopian farmers and has an important environmental and socioeconomic key role in the highlands area. The consumption of eucalypt is been boosted because of its compatibility with the grazing system and its high yields even in marginal agricultural soils of abandoned lands. However, farmers are lacking of start materials and the current techniques make production difficult.Within the improvement program, the researchers established an experimental test with eucalypt plants from Ethiopia and Spain in order to compare their potential productivity in local conditions. The Spanish plant, that had a certain rate of improvement, showed a growth and survival rate between 27% and 35%, a rate higher than the Ethiopian plants. …

Read more

Giant mass extinction quicker than previously thought: End-Permian extinction happened in 60,000 years

The largest mass extinction in the history of animal life occurred some 252 million years ago, wiping out more than 96 percent of marine species and 70 percent of life on land — including the largest insects known to have inhabited Earth. Multiple theories have aimed to explain the cause of what’s now known as the end-Permian extinction, including an asteroid impact, massive volcanic eruptions, or a cataclysmic cascade of environmental events. But pinpointing the cause of the extinction requires better measurements of how long the extinction period lasted.Now researchers at MIT have determined that the end-Permian extinction occurred over 60,000 years, give or take 48,000 years — practically instantaneous, from a geologic perspective. The new timescale is based on more precise dating techniques, and indicates that the most severe extinction in history may have happened more than 10 times faster than scientists had previously thought.”We’ve got the extinction nailed in absolute time and duration,” says Sam Bowring, the Robert R. Shrock Professor of Earth and Planetary Sciences at MIT. “How do you kill 96 percent of everything that lived in the oceans in tens of thousands of years? It could be that an exceptional extinction requires an exceptional explanation.”In addition to establishing the extinction’s duration, Bowring, graduate student Seth Burgess, and a colleague from the Nanjing Institute of Geology and Paleontology also found that, 10,000 years before the die-off, the oceans experienced a pulse of light carbon, which likely reflects a massive addition of carbon dioxide to the atmosphere. This dramatic change may have led to widespread ocean acidification and increased sea temperatures by 10 degrees Celsius or more, killing the majority of sea life.But what originally triggered the spike in carbon dioxide? The leading theory among geologists and paleontologists has to do with widespread, long-lasting volcanic eruptions from the Siberian Traps, a region of Russia whose steplike hills are a result of repeated eruptions of magma. To determine whether eruptions from the Siberian Traps triggered a massive increase in oceanic carbon dioxide, Burgess and Bowring are using similar dating techniques to establish a timescale for the Permian period’s volcanic eruptions that are estimated to have covered over five million cubic kilometers.”It is clear that whatever triggered extinction must have acted very quickly,” says Burgess, the lead author of a paper that reports the results in this week’s Proceedings of the National Academy of Sciences, “fast enough to destabilize the biosphere before the majority of plant and animal life had time to adapt in an effort to survive.”Pinning dates on an extinctionIn 2006, Bowring and his students made a trip to Meishan, China, a region whose rock formations bear evidence of the end-Permian extinction; geochronologists and paleontologists have flocked to the area to look for clues in its layers of sedimentary rock. …

Read more

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. …

Read more

New maps reveal locations of species at risk as climate changes

In research published today in the journal Nature, CSIRO and an international team of scientists revealed global maps showing how fast and in which direction local climates are shifting. This new study points to a simpler way of looking at climatic changes and their likely effects on biodiversity.As climate change unfolds over the next century, plants and animals will need to adapt or shift locations to track their ideal climate.”The maps show areas where plants and animals may struggle to find a new home in a changing climate and provide crucial information for targeting conservation efforts,” CSIRO’s Dr Elvira Poloczanska said.The study analyzed 50 years of sea surface and land temperature data (1960-2009) and also investigated two future scenarios for marine environments (‘business as usual’ and a 1.75C temperature increase).The new maps show where new thermal environments are being generated and where existing environments may disappear.”The maps show us how fast and in which direction temperatures are shifting, and where climate migrants following them may hit barriers such as coastlines. Our work shows that climate migration is far more complex than a simple shift towards the poles,” ecological geographer with the project Kristen Williams said.”Across Australia, species are already experiencing warmer temperatures. In terrestrial habitats, species have started to seek relief by moving to higher elevations, or further south. However, some species of animals and plants cannot move large distances, and some not at all.”Species migration can have important consequences for local biodiversity. For example, the dry, flat continental interior of Australia is a hot, arid region where species already exist close to the margin of their thermal tolerances.Some species driven south from monsoonal northern Australia in the hope of cooler habitats may perish in that environment.”In the oceans, warming waters and a strengthening of the East Australian Current have mobilised the Long-spined Sea Urchin (Centrostephanus rodgersii), previously only found as far south as southern NSW, to invade the eastern Tasmania coast. This has resulted in the decline of giant kelp forests with knock-on effects for commercially-fished rock lobsters,” Dr Poloczanska said.CSIRO and University of Queensland’s Anthony Richardson said the study cannot be used as a sole guide as to what to do in the face of climate change.”Biological factors such as a species’ capacity to adapt and disperse need to be taken into consideration,” Professor Richardson said.”But in an unprecedented period of climate change, economic development and fast growing demand on an already pressured planet, we need to act fast to make sure as much of the world’s living resources survive that change.”Story Source:The above story is based on materials provided by CSIRO Australia. Note: Materials may be edited for content and length.

Read more

A plant catalogued as extinct in Catalonia is rediscovered, Spanish researchers show

Spirodela polyrrhiza is the name of a small floating plant that was not found in the Mediterranean basin during more than 80 years. The plant, catalogued as extinct in Catalonia, has been found in the lower course of the Ebro River and the Vallvidrera reservoir (Catalonia, Spain). The finding in the Ebro River is described on an article published in the journal Flora Montiberica, authored by Nria Bonada, from the Department of Ecology of the UB, and scar Gavira and Tony Herrera Grao, from the company Mediodes Consultora Ambiental y Paisajismo.This scientific finding is also described on an article published in the journal Orsis 27 written by experts of the Scientific Research Group Terres de l’Ebre.A giant in the family of duckweedsThe species Spirodela polyrrhiza, which belongs to the family of duckweeds, has a miniature body reduced to a floating disc from which several roots hang, without stems or leaves. With a diameter of about 10 millimetres, S. polyrrhiza is considered a giant in the family of duckweeds (for instance, Wolffia arrhiza’s diameter is not longer than 1.5 millimetres).It has a world-wide distribution; it also lives in the Iberian Atlantic basin. In Catalonia, it was only thought to be in the area of L’Empord (Girona), and it was never identified before in the Ebro basin or the vicinity of Barcelona. In Catalonia, it was last referred in the 1980s in Rossell, and in the 19th century it was documented in Empries. When the plant disappeared in Catalonia, it also did it in the Iberian Mediterranean basin, as it was not identified any other hydrological point of this network.”The plant lives in swampy and shady areas, backwaters of rivers and marshes; it shares its habitat with other species of duckweeds and macrophytes,” explains Professor Nria Bonada, member of the Research Group Freshwater Ecology and Management (FEM) of UB.No idea of its presence for 80 yearsMore than 80 years later, S. polyrrhiza has been re-discovered in the lower course of the Ebro River, in Tarragona, and the Vallvidrera reservoir, near Barcelona. These findings are described in a study published recently on the Butllet of the Catalan Institute of Natural History (ICHN), coordinated by the expert Pere Aymerich.”The species was never identified again at its original location or in studies carried out in the Ebro River, so we think that it is an uncommon species that inhabits some particular habitats,” affirms Nria Bonada. …

Read more

Death by moonlight? Not always

Oct. 22, 2013 — Is moonlight dangerous? It depends on what you are, according to a study published online recently in the Journal of Animal Ecology.”Ecologists have long viewed the darkness of a moonless night as a protective blanket for nocturnal prey species,” said Laura Prugh, a wildlife biologist at the University of Alaska Fairbanks.In the dark, creatures of the night can go about their business in relative safety from lurking predators. Moonlight, according to this logic, helps predators find their prey and is risky if you are a prey species trying not to get eaten.That’s not always so, says Prugh, a researcher with the UAF Institute of Arctic Biology, and colleague Christopher Golden of Harvard University.”The theory that moonlight increases predation risk ignores the fact that prey animals also have eyes, and they often use them to detect predators,” said Prugh. If moonlight helps predators to find prey, it could also help prey species to detect approaching predators.To find out if moonlit nights are dangerous, Prugh and Golden compiled the effects of moonlight reported in existing studies of 58 nocturnal mammal species. If moonlight is dangerous for prey species, they expected predators to be more active on moonlit nights and prey species to be less active.The researchers found that species ranged widely in their affinity for moonlight, from the moon-loving or lunar-philic lemurs of Madagascar to the lunar-phobic kangaroo rats in the southwestern United States. And, responses to moonlight were related to the sensory systems of species rather than their positions in the food chain.Prey animals that use vision as their main sensory system, such as primates, were generally more active on bright nights. Prey species that rely mainly on senses like smell or echolocation, such as many rodents and bats, were generally less active. And contrary to expectations, predators such as African lions were less active on moonlit nights.”Moonlight is indeed risky for some prey species, but only those that use vision as a backup system rather than their first line of defense,” said Prugh. “Our synthesis shows that moonlight can benefit visually oriented prey.” And as for those lurking predators, the moon may often hurt rather than help their chances of catching prey.This study is the first to examine moonlight effects across a diverse assemblage of species. …

Read more

World’s first mapping of America’s rare plants

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

Gene regulation differences between humans, chimpanzees very complex

Oct. 17, 2013 — Changes in gene regulation have been used to study the evolutionary chasm that exists between humans and chimpanzees despite their largely identical DNA. However, scientists from the University of Chicago have discovered that mRNA expression levels, long considered a barometer for differences in gene regulation, often do not reflect differences in protein expression — and, therefore, biological function — between humans and chimpanzees. The work was published Oct. 17 in Science.”We thought that we knew how to identify patterns of mRNA expression level differences between humans and chimpanzees that would be good candidates to be of functional importance,” said Yoav Gilad, PhD, Professor of Human Genetics at the University of Chicago. “Now we see that even such mRNA patterns are not translated to the protein level. Which means that it is unlikely that they can affect a functional phenotypic difference.”For genes to be expressed, DNA must be transcribed into messenger RNA (mRNA), which then code for proteins, the biological building blocks and engines that drive cellular function. Although humans and chimpanzees share highly similar genomes, previous studies have shown that the species evolved major differences in mRNA expression levels. Many of these differences were thought to indicate areas of evolutionary divergence, thus pointing to genes important for human-specific traits.To test this, Gilad, Jonathan Pritchard, PhD, currently at Stanford University, and their team, spearheaded by postdoctoral fellow Zia Khan, PhD, used high-resolution mass spectrometry to compare the expression levels of thousands of proteins with corresponding mRNA expression data in human and chimpanzee cell lines.The team found 815 genes with differing mRNA expression levels but only 571 genes that differed in protein expression. In total, they identified an estimated 266 genes with mRNA differences that did not lead to changes in protein levels. …

Read more

Analysis of herbal products shows contamination is common

Oct. 10, 2013 — Most herbal products, available to buy as alternative medicines, may be contaminated. Reporting in BioMed Central’s open access journal BMC Medicine researchers demonstrate the presence of contamination and substitution of plant species in a selection of herbal products using DNA barcoding.Share This:There is currently no best practice for identifying plant species in herbal products. Traditionally plants are identified through the appearance of the whole plant. This method is not useful though when analyzing processed plant material. DNA barcoding analyses a short genetic sequence from the plant’s genome and identifies small differences that allows species identification. In this new study the researchers used barcoding to examine the plant species found in a sample of herbal plant products.The results showed that 59% of the products contained plant species not listed on the labels. Over two thirds of the products tested had plant species present which were a substitution for the plants listed on the label and a third of products also contained other species that may be a filler or contamination.According to the World Health Organization, the adulteration of herbal products is a threat to consumer safety. In this current analysis the researchers detected plant species that could pose serious health risks when consumed. The results revealed plant species with known toxicity, side effects and/or negatively interact with other herbs, supplements, or medications were present in some products.The authors concluded that the contamination and substitution dilute the effectiveness of otherwise useful remedies, lowering the perceived value of all related products because of a lack of consumer confidence in them. …

Read more

Is a constructive conservation the last chance for biodiversity? Pragmatic approach to saving what can be saved

Oct. 10, 2013 — How can biodiversity be preserved in a world in which traditional ecosystems are increasingly being displaced by “human-made nature”? Biologists at the TU Darmstadt and ETH Zurich have developed a new concept for conservation measures that incorporates current landscapes formerly considered ecologically “of little value.” Numerous experiences from islands have shown that this concept has a positive effect on biodiversity. Now the authors are proposing applying these lessons learned to other landscapes.In a human-dominated world that contains only little “historical” nature, the term ecosystem can no longer be a synonym for unspoilt nature. The term “novel ecosystems” was coined a few years ago to describe disturbed ecosystems in which biodiversity has been significantly altered as the result of human intervention. “In our new conservation framework we argue that this strict distinction between historic and novel ecosystems should be reconsidered to aid conservation,” pollination biologist Dr. Christopher Kaiser-Bunbury describes the approach, which is not without controversy.On continents with vast natural parks, such as the USA and Africa, critics fear that the new concept could weaken the protection of historic nature by, for instance, redirecting financial resources towards more active intervention and design of ecosystems. The team of Darmstadt and Zurich biologists, however, propagates a reconciling approach. “Our framework combines strategies that were, until now, considered incompatible. Not only historic wildlands are worth protecting, but also designed cultural landscapes. …

Read more

Longer life for humans linked to further loss of endangered species

Oct. 9, 2013 — As human life expectancy increases, so does the percentage of invasive and endangered birds and mammals, according to a new study by the University of California, Davis.The study, published in the September issue of Ecology and Society, examined a combination of 15 social and ecological variables — from tourism and per capita gross domestic product to water stress and political stability. Then researchers analyzed their correlations with invasive and endangered birds and mammals, which are two indicators of what conservationist Aldo Leopold termed “land sickness,” the study said.Human life expectancy, which is rarely included among indexes that examine human impacts on the environment, surfaced as the key predictor of global invasions and extinctions.”It’s not a random pattern,” said lead author Aaron Lotz, a postdoctoral scholar in the Department of Wildlife, Fish and Conservation Biology when the study was conducted. “Out of all this data, that one factor — human life expectancy — was the determining factor for endangered and invasive birds and mammals.”The study analyzed data from 100 countries, which included roughly 87 percent of the world’s population, 43 percent of global GDP per capita, and covered 74 percent of Earth’s total land area. Additional factors considered were agricultural intensity, rainfall, pesticide regulation, energy efficiency, wilderness protection, latitude, export-import ratio, undernourishment, adult literacy, female participation in government, and total population.The findings include:New Zealand, the United States and the Philippines had among the highest percentages of endangered and invasive birds. New Zealand had the highest percentage of all endangered and invasive species combined, largely due to its lack of native terrestrial mammals. The study said that in the past 700 to 800 years since the country was colonized, it has experienced massive invasion by nonindigenous species, resulting in catastrophic biodiversity loss. African countries had the lowest percentage of invasive and endangered birds and mammals. These countries have had very little international trade, which limits opportunities for biological invasion. As GDP per capita — a standard measure of affluence — increased in a country, so did the percentage of invasive birds and mammals. …

Read more

Rare fossil ape cranium discovered in China

Sep. 6, 2013 — A team of researchers has discovered the cranium of a fossil ape from Shuitangba, a Miocene site in Yunnan Province, China. The juvenile cranium of the fossil ape Lufengpithecus is significant, according to team member Nina Jablonski, Distinguished Professor of Anthropology at Penn State.Jablonski noted that juvenile crania of apes and hominins are extremely rare in the fossil record, especially those of infants and young juveniles. This cranium is only the second relatively complete cranium of a young juvenile in the entire Miocene — 23-25 million years ago — record of fossil apes throughout the Old World, and both were discovered from the late Miocene of Yunnan Province.The cranium is also noteworthy for its age. Shuitangba, the site from which it was recovered, at just over 6 million years old, dates to near the end of the Miocene, a time when apes had become extinct in most of Eurasia. Shuitangba has also produced remains of the fossil monkey, Mesopithecus, which represents the earliest occurrence of monkeys in East Asia.Jablonski was co-author of a recent paper online in the Chinese Science Bulletin that described the discovery.”The preservation of the new cranium is excellent, with only minimal post-depositional distortion,” Jablonski said. “This is important because all previously discovered adult crania of the species to which it is assigned, Lufengpithecus lufengensis, were badly crushed and distorted during the fossilization process. In living ape species, cranial anatomy in individuals at the same stage of development as the new fossil cranium already show a close resemblance to those of adults.”Therefore, the new cranium, despite being from a juvenile, gives researchers the best look at the cranial anatomy of Lufengpithecus lufengensis.”Partly because of where and when Lufengpithecus lived, it is considered by most to be in the lineage of the extant orangutan, now confined to Southeast Asia but known from the late Pleistocene of southern China as well,” Jablonski said.However, the researchers noted the cranium shows little resemblance to those of living orangutans, and in particular, shows none of what are considered to be key diagnostic features of orangutan crania. Lufengpithecus therefore appears to represent a late surviving lineage of Eurasian apes, but with no certain affinities yet clear.The survival of this lineage is not entirely surprising since southern China was less affected by climatic deterioration during the later Miocene that resulted in the extinction of many ape species throughout the rest of Eurasia. The researchers are hopeful that further excavations will produce the remains of adult individuals, which will allow them to better assess the relationships among members of this lineage as well as the relationships of this lineage to other fossil and extant apes.

Read more

Simian foamy viruses readily occur between humans and macaques in urban Bangladesh

Sep. 4, 2013 — Throughout Asia, humans and monkeys live side-by side in many urban areas. An international research team from the University of Washington, Fred Hutchinson Cancer Research Center and Jahangirnagar University has been examining transmission of a virus from monkeys to humans in Bangladesh, one of the world’s most densely populated countries. The scientists have found that some people in these urban areas are concurrently infected with multiple strains of simian foamy virus (SFV), including strains from more than one source (recombinant) that researchers originally detected in the monkeys.Simian foamy viruses, which are ubiquitous in nonhuman primates, are retroviruses like HIV. Retroviruses are shown to exhibit high levels of mutation and recombination — a potentially explosive combination.Their paper, “Zoonotic simian foamy virus in Bangladesh reflects diverse patterns of transmission and co-infection” published in the Sept. 4 issue of Emerging Microbes and Infections (EMI), characterizes the simian retroviral strains that are being zoonotically transmitted and provides a glimpse into the behaviors of humans and monkeys contributing to the infections.By analyzing what is happening at the human-primate interface, the researchers hope to protect humans from another deadly outbreak like HIV. Their focus is in Asia because it is a continent that has witnessed the emergence of several infectious diseases in the past decade. Asia also has a volatile combination of an increasingly mobile and immunocompromised population living in proximity with animals.Since more humans have been shown to have been infected with SFV through primate contact than with any other simian-borne virus, the researchers reason that pinpointing the factors that influence SFV transmission and infection are important to a general understanding of how viruses can jump the species barrier.”If we want to understand how, where and why these primate viruses are being transmitted, we need to be looking at SFV in Asia where millions of people and tens of thousands of macaques are interacting everyday and where we estimate that thousands of people could be infected with strains of SFV,” said Lisa Jones-Engel, a primatologist with the National Primate Research Center at the University of Washington and the project leader. “These Asian rhesus macaques are Darwinian superstars. They are very responsive to change and, unlike many other species of primates, they are going to continue to thrive in human-altered habitats.”Jones-Engel said if researchers had been on the ground 50 years ago, they may have seen how simian immunodeficiency viruses (SIV) crossed the species barrier resulting in HIV.”We have been playing catch up with the SIV-HIV question for years,” she said. …

Read more

Utilizzando il sito, accetti l'utilizzo dei cookie da parte nostra. maggiori informazioni

The cookie settings on this website are set to "allow cookies" to give you the best browsing experience possible. If you continue to use this website without changing your cookie settings or you click "Accept" below then you are consenting to this.

Close