Researchers work to save endangered New England cottontail

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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. …


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Temperature and ecology: Rival Chilean barnacles keep competition cool

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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. …


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Zebrafish discovery may shed light on human kidney function

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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. …


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

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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. …


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Poaching threatens savannah ecosystems

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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). …


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

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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.


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Eucalypt in Ethiopian highlands: Increasing productivity of important tree

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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. …


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

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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. …


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Crocodilians can climb trees and bask in the tree crowns

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


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New maps reveal locations of species at risk as climate changes

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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.


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