Insights into birds’ migration routes

Date:July 21, 2014Source:WileySummary:By tracking hybrids between songbird species, investigators have found that migration routes are under genetic control and could be preventing interbreeding. The research was conducted using geolocators that, like GPS, record the position of a bird and allow its long distance movement to be tracked.By tracking hybrids between songbird species, investigators have found that migration routes are under genetic control and could be preventing interbreeding. The research, which is published in Ecology Letters, was conducted using geolocators that, like GPS, record the position of a bird and allow its long distance movement to be tracked.Compared with their parents, hybrids exhibited increased variability in their migratory routes: some used intermediate routes across less suitable areas, while others used the same routes as one parental group on fall migration and the other on spring migration.”This is the first time we’ve been able to track songbirds over the entire annual cycle, and the data we collected support a longstanding hypothesis in ecological speciation, that differences in migratory behavior could be acting as postmating reproductive isolating barriers,” said lead author Kira Delmore.Story Source:The above story is based on materials provided by Wiley. Note: Materials may be edited for content and length.Journal Reference:Kira E. Delmore, Darren E. Irwin. Hybrid songbirds employ intermediate routes in a migratory divide. Ecology Letters, 2014; DOI: 10.1111/ele.12326 Cite This Page:MLA APA Chicago Wiley. “Insights into birds’ migration routes.” ScienceDaily. ScienceDaily, 21 July 2014. …

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Vulnerability of sharks as collateral damage in commercial fishing shown by study

A new study that examined the survival rates of 12 different shark species when captured as unintentional bycatch in commercial longline fishing operations found large differences in survival rates across the 12 species, with bigeye thresher, dusky, and scalloped hammerhead being the most vulnerable. The study, led by researchers at the University of Miami (UM) Rosenstiel School of Marine and Atmospheric Science and UM Abess Center for Ecosystem Science and Policy, provides new information to consider for future conservation measures for sharks in the Northwest Atlantic. The unintentional capture of a fish species when targeting another species, known as bycatch, is one of the largest threats facing many marine fish populations.Researchers from UM and the National Marine Fisheries Service analyzed over 10 years of shark bycatch data from the western Atlantic Ocean and Gulf of Mexico tuna and swordfish longline fisheries to examine how survival rates of sharks were affected by fishing duration, hook depth, sea temperature, animal size and the target fish. Some species, such as the tiger shark, exhibited over 95% survival, whereas other species survival was significantly lower, in the 20-40% range, such as night shark and scalloped hammerheads.”Our study found that the differences in how longline fishing is actually conducted, such as the depth, duration, and time-of-day that the longlines are fished can be a major driver of shark survival, depending on the species,” said UM Rosenstiel School Ph.D student and lead author Austin Gallagher. “At-vessel mortality is a crucial piece of the puzzle in terms of assessing the vulnerability of these open-ocean populations, some of which are highly threatened.”The researchers also generated overall vulnerability rankings of species taking into account not only their survival, but also reproductive potential. They found that species most at risk were those with both very slow reproductive potential and unusual body features, such as hammerheads and thresher sharks. The paper’s authors suggest that bycatch likely played an important role in the decline of scalloped hammerhead species in the Northwest Atlantic, which has been considered for increased international and national protections, such as the U.S. Endangered Species List.The researchers suggest that high at-vessel mortality, slow maturity, and specialized body structures combine for the perfect mixture to become extinction-prone.”Our results suggest that some shark species are being fished beyond their ability to replace themselves,” said UM Research Assistant Professor Neil Hammerschlag. “Certain sharks, such as big eye threshers and scalloped hammerheads, are prone to rapidly dying on the line once caught and techniques that reduce their interactions with fishing gear in the first place may be the best strategy for conserving these species.”The study, titled “Vulnerability of oceanic sharks as pelagic longline bycatch” was published online in the open-access journal Global Ecology and Conservation.Story Source:The above story is based on materials provided by University of Miami Rosenstiel School of Marine & Atmospheric Science. Note: Materials may be edited for content and length.

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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. …

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Calcification in changing oceans

What do mollusks, starfish, and corals have in common? Aside from their shared marine habitat, they are all calcifiers — organisms that use calcium from their environment to create hard carbonate skeletons and shells for stability and protection.The June issue of the Biological Bulletin, published by the Marine Biological Laboratory, addresses the challenges faced by these species as ocean composition changes worldwide.As atmospheric carbon dioxide rises, the world’s oceans are becoming warmer and more acidic. This impact of global climate change threatens the survival of calcifying species because of the reduced saturation of the carbonate minerals required for calcification.The ability to calcify arose independently in many species during the Cambrian era, when calcium levels in seawater increased. This use of calcium carbonate promoted biodiversity, including the vast array of calcifiers seen today.”Today, modern calcifiers face a new and rapidly escalating crisis caused by warming and acidification of the oceans with a reduction in availability of carbonate minerals, a change driven by the increase in atmospheric CO2 due to anthropogenic emissions and industrialization. The CO2 itself can also directly cause metabolic stress,” write the issue’s co-editors, Maria Byrne of the University of Sydney; and Gretchen Hofmann of the University of California-Santa Barbara.Contributors to the journal address this timely issue across many taxa and from a variety of perspectives, from genomic to ecosystem-wide.Janice Lough and Neal Cantin of the Australian Institute of Marine Science review historical data on coral reefs to look at potential environmental stressors, while Philippe Dubois (Universit Libre de Bruxelles) discusses sea urchin skeletons.Other researchers address lesser-known organisms that are nevertheless critical to marine ecosystems. Abigail Smith of the University of Otago examines how bryozoans, a group of aquatic invertebrate filter-feeders, increase biodiversity by creating niche habitats, and what features make them particularly sensitive to calcium fluctuations.Evans and Watson-Wynn (California State University-East Bay) take a molecular approach in a meta-analysis showing that ocean acidification is effecting genetic changes in sea urchin larvae. Several papers take a broader population-based view by studying the effect of ocean acidification on predator-prey interactions in mollusks (Kroeker and colleagues of the University of California-Davis) and oysters (Wright and colleagues of the University of Western Sydney).”The contributors have identified key knowledge gaps in the fast evolving field of marine global change biology and have provided many important insights,” the co-editors write.By sharing research on this topic from researchers around the world, the Biological Bulletin is raising awareness of some of the greatest threats to the oceans today and emphasizing the global nature of the problem.Story Source:The above story is based on materials provided by The Marine Biological Laboratory. The original article was written by Gina Hebert. Note: Materials may be edited for content and length.

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Biologist warn of early stages of Earth’s sixth mass extinction event

The planet’s current biodiversity, the product of 3.5 billion years of evolutionary trial and error, is the highest in the history of life. But it may be reaching a tipping point.In a new review of scientific literature and analysis of data published in Science, an international team of scientists cautions that the loss and decline of animals is contributing to what appears to be the early days of the planet’s sixth mass biological extinction event.Since 1500, more than 320 terrestrial vertebrates have become extinct. Populations of the remaining species show a 25 percent average decline in abundance. The situation is similarly dire for invertebrate animal life.And while previous extinctions have been driven by natural planetary transformations or catastrophic asteroid strikes, the current die-off can be associated to human activity, a situation that the lead author Rodolfo Dirzo, a professor of biology at Stanford, designates an era of “Anthropocene defaunation.”Across vertebrates, 16 to 33 percent of all species are estimated to be globally threatened or endangered. Large animals — described as megafauna and including elephants, rhinoceroses, polar bears and countless other species worldwide — face the highest rate of decline, a trend that matches previous extinction events.Larger animals tend to have lower population growth rates and produce fewer offspring. They need larger habitat areas to maintain viable populations. Their size and meat mass make them easier and more attractive hunting targets for humans.Although these species represent a relatively low percentage of the animals at risk, their loss would have trickle-down effects that could shake the stability of other species and, in some cases, even human health.For instance, previous experiments conducted in Kenya have isolated patches of land from megafauna such as zebras, giraffes and elephants, and observed how an ecosystem reacts to the removal of its largest species. Rather quickly, these areas become overwhelmed with rodents. Grass and shrubs increase and the rate of soil compaction decreases. Seeds and shelter become more easily available, and the risk of predation drops.Consequently, the number of rodents doubles — and so does the abundance of the disease-carrying ectoparasites that they harbor.”Where human density is high, you get high rates of defaunation, high incidence of rodents, and thus high levels of pathogens, which increases the risks of disease transmission,” said Dirzo, who is also a senior fellow at the Stanford Woods Institute for the Environment. …

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East African honeybees safe from invasive pests … for now

Several parasites and pathogens that devastate honeybees in Europe, Asia and the United States are spreading across East Africa, but do not appear to be impacting native honeybee populations at this time, according to an international team of researchers.The invasive pests include including Nosema microsporidia and Varroa mites.”Our East African honeybees appear to be resilient to these invasive pests, which suggests to us that the chemicals used to control pests in Europe, Asia and the United States currently are not necessary in East Africa,” said Elliud Muli, senior lecturer in the Department of Biological Sciences, South Eastern Kenya University, and researcher at the International Centre of Insect Physiology and Ecology, Kenya.The team first discovered Varroa mites in Kenya in 2009. This new study also provides baseline data for future analyses of possible threats to African honeybee populations.”Kenyan beekeepers believe that bee populations have been experiencing declines in recent years, but our results suggest that the common causes for colony losses in the United States and Europe — parasites, pathogens and pesticides — do not seem to be affecting Kenyan bees, at least not yet,” said Christina Grozinger, professor of entomology and director of the Center for Pollinator Research, Penn State. “Some of our preliminary data suggest that the loss of habitat and drought impacting flowering plants, from which the bees get all their food, may be the more important factor driving these declines.”According to Harland Patch, research scientist in entomology, Penn State, not only are flowering plants important for honeybees, but the insects are important for plants as well.”Honeybees are pollinators of untold numbers of plants in every ecosystem on the African continent,” Patch said. “They pollinate many food crops as well as those important for economic development, and their products, like honey and wax, are vital to the livelihood of many families. People say the greatest animal in Africa is the lion or the elephant, but honeybees are more essential, and their decline would have profound impacts across the continent.”In 2010, the researchers conducted a nationwide survey of 24 locations across Kenya to evaluate the numbers and sizes of honeybee colonies, assess the presence or absence of Varroa and Nosema parasites and viruses, identify and measure pesticide contaminants in hives and determine the genetic composition of the colonies.”This is the first comprehensive survey of bee health in East Africa, where we have examined diseases, genetics and the environment to better understand what factors are most important in bee health in this region,” said Grozinger. The results appeared today in PLOS ONE.The researchers found that Varroa mites were present throughout Kenya, except in the remote north. In addition, Varroa numbers increased with elevation, suggesting that environmental factors may play a role in honeybee host-parasite interactions. Most importantly, the team found that while Varroa infestation dramatically reduces honeybee colony survival in the United States and Europe, in Kenya, its presence alone does not appear to impact colony size.The scientists found Nosema at three sites along the coast and one interior site. At all of the sites, they found only a small number of pesticides at low concentrations. Of the seven common honeybee viruses in the United States and Europe, the team only identified three species, but, like Varroa, these species were absent from northern Kenya. …

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Improving understanding of valley-wide stream chemistry

A geostatistical approach for studying environmental conditions in stream networks and landscapes has been successfully applied at a valley-wide scale to assess headwater stream chemistry at high resolution, revealing unexpected patterns in natural chemical components.”Headwater streams make up the majority of stream and river length in watersheds, affecting regional water quality,” said Assistant Professor Kevin J. McGuire, associate director of the Virginia Water Resources Research Center in Virginia Tech’s College of Natural Resources and Environment. “However, the actual patterns and causes of variation of water quality in headwater streams are often unknown.””Understanding the chemistry of these streams at a finer scale could help to identify factors impairing water quality and help us protect aquatic ecosystems,” said Gene E. Likens, president emeritus and distinguished senior scientist emeritus with the Cary Institute of Ecosystem Studies and the University of Connecticut.Results of the study that used a new statistical tool to describe spatial patterns of water chemistry in stream networks are published in the April 21 issue of the Proceedings of the National Academies of Science by a team of ecosystem scientists, including McGuire and Likens.The data used in the new analysis consist of 664 water samples collected every 300 feet throughout all 32 tributaries of the 14-square-mile Hubbard Brook Valley in New Hampshire. The chemistry results were originally reported in 2006 in the journal Biogeochemistry by Likens and Donald C. Buso, manager of field research with the Cary Institute.McGuire and other members of the National Science Foundation’s Long-Term Ecological Research team at the Hubbard Brook Ecosystem Study decided that the huge, high-resolution dataset was ideal for a new statistical approach that examines how water flows both within the stream network and across the landscape.”The goal was to visualize patterns that no one has been able to quantify before now and describe how they vary within headwater stream networks,” said McGuire. “Some chemical constituents vary at a fine scale, that is patterns of chemical change occur over very short distances, for example several hundred feet, but some constituents vary over much larger scales, for example miles. Several chemical constituents that we examined even varied at multiple scales suggesting that nested processes within streams and across the landscape influence the chemistry of stream networks.””The different spatial relationships permit the examination of patterns controlled by landscape versus stream network processes,” the article reports. Straight-line and unconnected network spatial relationships indicate landscape influences, such as soil, geology, and vegetation controls of water chemistry, for instance. In contrast, flow-connected relationships provide information on processes affected within the flowing streams.The researchers are very familiar with the Hubbard Brook Valley and could point to the varying influences of the geology and distinct soil types, including areas of shallow acidic organic-rich soils.The findings revealed by the analysis technique showed how chemistry patterns vary across landscapes with two scales of variation, one around 1,500 feet and another at about 4 miles. …

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Putting a price on ecological restoration

Putting a price on clean water and soil fertility helps the UN set ecological restoration targets for degraded and deforested land.Forests provide essential ecosystem services for people, including timber, food and water. For those struggling with the after-effects of deforestation, the main hope lies in rebuilding forest resources through ecological restoration.Researchers at BU have shown that placing a monetary value on ecosystem services provides a mechanism for evaluating the costs and benefits of reforestation activity.”Ecological restoration initiatives are being undertaken around the world, attracting investment of $US billions annually,” explained Professor Adrian Newton. “They make a significant contribution to sustainable development but few attempts have been made to systematically evaluate their effectiveness.”To address this knowledge gap, Professor Newton and fellow BU researchers analysed 89 different types of restored ecosystem sites across the world. The results showed that, although restored land was not as productive as land that had not been degraded, restoration efforts increased biodiversity by 44% and provision of ecosystem services by 25%.What’s unique about Professor Newton’s research is that it also provides one of the first evidence-based assessments of how cost-effective ecological restoration initiatives actually are.Professor Newton developed this method as part of the ReForLan research project in the dryland forests of Latin America. ReForLAn brought together researchers from six countries to assess the environmental degradation and the potential for ecological recovery through restoration.The methodology assigns financial value to ecosystem services, such as the provision of clean water, carbon storage and soil fertility that would result from restoration, thereby demonstrating how cost effective these efforts are.”We examined whether ecological restoration can be cost effective, based on the value of ecosystem services provided by restoration actions,” he explained. “This was undertaken by analysing the value of the increased provision of ecosystem services that could potentially be provided as a result of ecological restoration actions.”So successful is the methodology that it was used to inform the United Nations Environment Programme’s restoration targets and specifically ‘Target 15’ of the Aichi Biodiversity Targets to restore 15% of the world’s degraded ecosystems by 2020.The UN say these targets can be achieved through Forest Landscape Restoration, which is an approach developed, tested and refined by Professor Newton during the ReForLan project.”We examined how Forest Landscape Restoration may be implemented in practice, and evaluated the cost effectiveness of this approach and its benefit to human communities,” he explained.Professor Newton has demonstrated that at the heart of successful forest landscape restoration is a flexible and adaptive approach. It should allow communities to participate in the decision-making process, and enhance ecosystem service provision for those living within them.The Forest Landscape Restoration method has been heralded as the solution to restoring 150 million acres of degraded and deforested land. This target is part of a global movement, known as ‘Bonn Challenge’, named from its inception in Bonn, Germany in 2011. Individual countries have so far committed to restoring 50 million hectares of forest, which is a significant step towards achieving the policy goals.”This initiative directly employs the Forest Landscape Restoration approach that we researched, developed, tested and refined,” explains Professor Newton.He conclude, “Ecosystems are a rich source of biodiversity and the services they provide are relied upon by local people. The approach developed through the ReForLan project allows policy makers to identify locations where ecological restoration is most likely to be cost effective.”ReForLan was funded by the European Commission and the full title of the project is ‘Restoration of Forest Landscapes for Biodiversity Conservation and Rural Development’.Story Source:The above story is based on materials provided by Bournemouth University. …

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Amazon Studied to Predict Impact of Climate Change

Three extreme weather events in the Amazon Basin in the last decade are giving scientists an opportunity to make observations that will allow them to predict the impacts of climate change and deforestation on some of the most important ecological processes and ecosystem services of the Amazon River wetlands.Scientists from Virginia Tech, the Woods Hole Research Center, and the University of California, Santa Barbara, funded by NASA, are collaborating with Brazilian scientists to explore the ecosystem consequences of the extreme droughts of 2005 and 2010 and the extreme flood of 2009.”The research fills an important gap in our understanding of the vulnerability of tropical river-forest systems to changes in climate and land cover,” said the project’s leader, Leandro Castello, assistant professor of fish and wildlife conservation in Virginia Tech’s College of Natural Resources and Environment.The huge study area encompasses 1.7 million square miles, the equivalent of half of the continental United States.In addition to historical records and ground observations, the researchers will use newly available Earth System Data Records from NASA — satellite images of the Amazon and its tributaries over the complete high- and low-water cycles.NASA is funding the study with a $1.53 million grant shared among the three institutions.”Amazon floodplains and river channels — maintained by seasonal floods — promote nutrient cycling and high biological production, and support diverse biological communities as well as human populations with one of the highest per capita rates of fish consumption,” said Castello.The researchers will look at how the natural seasonality of river levels influences aquatic and terrestrial grasses, fisheries, and forest productivity in the floodplains, and how extreme events such as floods and droughts may disturb this cycle.”We are confident that deforestation and climate change will, in the future, lead to more frequent and severe floods and droughts,” said Michael Coe, a senior scientist at the Woods Hole Research Center. “It is important that we understand how the Amazon River and ecosystem services such as fisheries are affected so that we can devise mitigation strategies.”Amazonian grasses, sometimes called macrophytes, convert atmospheric carbon to plant biomass, which is then processed by aquatic microorganisms upon decomposition.”Terrestrial grasses grow during the short window when water levels are low, sequestering some carbon, and then die when the floods arrive, releasing the carbon into the aquatic system,” said Thiago Silva, an assistant professor of geography at So Paulo State University in Rio Claro, Brazil. “They are followed by aquatic grasses that need to grow extremely fast to surpass the rising floods and then die off during the receding-water period.””Although most of the macrophyte carbon is released back to the atmosphere in the same form that it is assimilated, carbon dioxide, some of it is actually exported to the ocean as dissolved carbon or released to the atmosphere as methane, a gas that has a warming potential 20 times larger than carbon dioxide,” said John Melack, a professor at the University of California, Santa Barbara.Researchers will measure plant growth and gas exchange, and use photographs from the field and satellites.Two other Amazon resources — fisheries and forests — are important to the livelihood of the people of the region.”We will combine water level, fishing effort, and fish life-history traits to understand the impact of droughts and floods on fishery yields,” said Castello, whose specialty is Amazon fisheries. “Floods in the Amazon are almost a blessing because in some years they can almost double the amount of fish in the river that is available for fishermen and society.”The fishery data include approximately 90,000 annual interview records of fisheries activities on the number of fishers, time spent fishing, characteristics of fishing boats and gear used, and weight of the catch for 40 species. The hydrological data include daily water level measurements recorded in the Madeira, Purus, and Amazonas-Solimes rivers.The researchers will examine the potential impact of future climate scenarios on the extent and productivity of floodplain forests — those enriched by rising waters, called whitewater river forests, and nutrient-poor blackwater river forests.For example, extreme droughts may reduce productivity due to water stress and increases in the frequency and severity of forest fires. Prolonged periods of inundation, on the other hand, may decrease productivity or increase mortality due to water-logging stress.”We will evaluate these responses for the first time at a regional scale using remotely sensed indicators of vegetation condition and fire-induced tree mortality to measure the response of floodplain forests to inter-annual flood variability and extreme climate events,” said Marcia Macedo, a research associate at the Woods Hole Research Center.Researchers will measure tree litter dry weight, depth of flooding, tree height and diameter, and stand density. They will also use photographs and satellite images.Previous research has focused on Amazon upland forests and the potential impacts of deforestation, fire, and drought. The research team will compare new greenhouse gas simulations to previous simulations.”Our research informs large river ecology globally because natural flowing rivers like the Amazon are rare these days, and most research to date, being done in North America and Europe, has focused on degraded systems,” Castello said.

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Deforestation of sandy soils a greater climate threat

Deforestation may have far greater consequences for climate change in some soils than in others, according to new research led by Yale University scientists — a finding that could provide critical insights into which ecosystems must be managed with extra care because they are vulnerable to biodiversity loss and which ecosystems are more resilient to widespread tree removal.In a comprehensive analysis of soil collected from 11 distinct U.S. regions, from Hawaii to northern Alaska, researchers found that the extent to which deforestation disturbs underground microbial communities that regulate the loss of carbon into the atmosphere depends almost exclusively on the texture of the soil. The results were published in the journal Global Change Biology.”We were astonished that biodiversity changes were so strongly affected by soil texture and that it was such an overriding factor,” said Thomas Crowther, a postdoctoral fellow at the Yale School of Forestry & Environmental Studies and lead author of the study. “Texture overrode the effects of all the other variables that we thought might be important, including temperature, moisture, nutrient concentrations, and soil pH.”The study is a collaboration among Yale researchers and colleagues at the University of Boulder, Colorado and the University of Kentucky.A serious consequence of deforestation is extensive loss of carbon from the soil, a process regulated by subterranean microbial diversity. Drastic changes to the microbial community are expected to allow more CO2 to escape into the atmosphere, with the potential to exaggerate global warming.Specifically, the researchers found that deforestation dramatically alters microbial communities in sandy soils, but has minimal effects in muddy, clay-like soils, even after extensive tree removal.According to the researchers, particles in fine, clay-like soil seem to have a larger surface area to bind nutrients and water. This capacity might buffer soil microbes against the disturbance of forest removal, they said. In contrast, sandy soils have larger particles with less surface area, retaining fewer nutrients and less organic matter.”If you disrupt the community in a sandy soil, all of the nutrients the microbes rely on for food are leached away: they’re lost into the atmosphere, lost into rivers, lost through rain,” Crowther said. “But in clay-like soil, you can cut down the forest and the nutrients remain trapped tightly in the muddy clay.”The researchers also examined how the effects of deforestation on microbial biodiversity change over time. Contrary to their expectations, they found no correlation, even over the course of 200 years.”The effects are consistent, no matter how long ago deforestation happened,” Crowther said. “In a clay soil, you cut down the forest and the nutrients are retained for long periods of time and the community doesn’t change. …

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Agroforestry systems can repair degraded watersheds

Agroforestry, combined with land and water management practices that increase agricultural productivity, can save watersheds from degradation.A study conducted by the World Agroforestry Centre (ICRAF) in the Gabayan watershed in eastern Bohol, Philippines, has shown that agroforestry systems create a more sustainably managed watershed that allows people living there to benefit from the ecosystem. The benefits include higher crop yields, increased income and resilience to climate change.Agroforestry is an integrated land-use management technique that incorporates trees and shrubs with crops and livestock on farms.The study, called “Modeling the effects of adopting agroforestry on basin scale surface runoff and sediment yield in the Philippines,” uses a computer-based Soil and Water Assessment Tool (SWAT) to simulate the effects of different land uses on watershed hydrology and the ecosystem services provided by the Gabayan watershed. The tool predicts the environmental impact of land use, land management practices, and climate change.Watersheds are areas of land with streams and rivers that all drain into a larger body of water, such as a bigger river, a lake or an ocean. Watersheds not only supply water for domestic use but also provide a multitude of ecological and cultural services, including water for irrigation and industry, shelter, habitats for biodiversity and, in very poor areas, sources of livelihoods.Over the years, however, many watersheds throughout the world have suffered from intensive resource extraction and mismanagement. In countries like the Philippines, several watershed areas in the country are now degraded due to deforestation and soil erosion.The Gabayan watershed incorporates a heavily degraded, multi-use landscape covering over 5000 hectares hosting about 60,000 people whose livelihoods depend on subsistence agricultureFarmers here have reported environmental problems, such as floods, droughts, reductions in water quality and increases in soil erosion and downstream sedimentation of irrigation networks.”The degraded watershed has been largely deforested and replaced with extensive agricultural and grasslands over the last half century,” says David Wilson, the lead researcher. “It has disrupted the evenness of river flow, resulting in alternate flooding and drought episodes, an accelerated level of soil erosion as well as downstream sedimentation.”SWAT was used to simulate the impacts of current land-use practices and conservation agriculture with agroforestry in strategic locations. The study results showed a significant reduction in sediment yield (20%) and sediment concentration (35%)in the Gabayan watershed under agroforestry and conservation agriculture.The study was therefore able to provide scientific evidence that agroforestry, combined with improved land management practices, are an effective land-use strategy for the watersheds.”Specifically, the use of restored areas that have vegetation next to water resources and contour planting in grasslands appear to be the most effective techniques to reduce sediment transfer to the watershed river network,” says Wilson.Story Source:The above story is based on materials provided by World Agroforestry Centre (ICRAF). Note: Materials may be edited for content and length.

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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. …

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The first insects were not yet able to smell well: Odorant receptors evolved long after insects migrated from water to land

An insect’s sense of smell is vital to its survival. Only if it can trace even tiny amounts of odor molecules is it is able to find food sources, communicate with conspecifics, or avoid enemies. According to scientists at the Max Planck Institute for Chemical Ecology, many proteins involved in the highly sensitive odor perception of insects emerged rather late in the evolutionary process. The very complex olfactory system of modern insects is therefore not an adaptation to a terrestrial environment when ancient insects migrated from water to land, but rather an adaptation that appeared when insects developed the ability to fly. The results were published in the Open Access Journal eLIFE.Many insect species employ three families of receptor proteins in order to perceive thousands of different environmental odors. Among them are the olfactory receptors. They form a functional complex with another protein, the so-called olfactory receptor co-receptor, which enables insects to smell the tiniest amounts of odor molecules in their environment very rapidly.Crustaceans and insects share a common ancestor. Since crustaceans do not have olfactory receptors, previously scientists assumed that these receptors evolved as an adaptation of prehistoric insects to a terrestrial life. This hypothesis is also based on the assumption that for the ancestors of recent insects, the ability to detect odor molecules in the air rather than dissolved in water was of vital importance.Early research on insect olfactory receptors focused entirely on insects with wings. Ewald Groe-Wilde and Bill S. …

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A more potent greenhouse gas than carbon dioxide, methane emissions will leap as Earth warms

While carbon dioxide is typically painted as the bad boy of greenhouse gases, methane is roughly 30 times more potent as a heat-trapping gas. New research in the journal Nature indicates that for each degree that Earth’s temperature rises, the amount of methane entering the atmosphere from microorganisms dwelling in lake sediment and freshwater wetlands — the primary sources of the gas — will increase several times. As temperatures rise, the relative increase of methane emissions will outpace that of carbon dioxide from these sources, the researchers report.The findings condense the complex and varied process by which methane — currently the third most prevalent greenhouse gas after carbon dioxide and water vapor — enters the atmosphere into a measurement scientists can use, explained co-author Cristian Gudasz, a visiting postdoctoral research associate in Princeton’s Department of Ecology and Evolutionary Biology. In freshwater systems, methane is produced as microorganisms digest organic matter, a process known as “methanogenesis.” This process hinges on a slew of temperature, chemical, physical and ecological factors that can bedevil scientists working to model how Earth’s systems will contribute, and respond, to a hotter future.The researchers’ findings suggest that methane emissions from freshwater systems will likely rise with the global temperature, Gudasz said. But to not know the extent of methane contribution from such a widely dispersed ecosystem that includes lakes, swamps, marshes and rice paddies leaves a glaring hole in climate projections.”The freshwater systems we talk about in our paper are an important component to the climate system,” Gudasz said. “There is more and more evidence that they have a contribution to the methane emissions. Methane produced from natural or humanmade freshwater systems will increase with temperature.”To provide a simple and accurate way for climate modelers to account for methanogenesis, Gudasz and his co-authors analyzed nearly 1,600 measurements of temperature and methane emissions from 127 freshwater ecosystems across the globe.The researchers found that a common effect emerged from those studies: freshwater methane generation very much thrives on high temperatures. Methane emissions at 0 degrees Celsius would rise 57 times higher when the temperature reached 30 degrees Celsius, the researchers report. For those inclined to model it, the researchers’ results translated to a temperature dependence of 0.96 electron volts (eV), an indication of the temperature-sensitivity of the methane-emitting ecosystems.”We all want to make predictions about greenhouse gas emissions and their impact on global warming,” Gudasz said. “Looking across these scales and constraining them as we have in this paper will allow us to make better predictions.”Story Source:The above story is based on materials provided by Princeton University. …

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Dynamics behind Arctic ecosystems revealed

Species such as the musk ox, Arctic fox and lemming live in the harsh, cold and deserted tundra environment. However, they have often been in the spotlight when researchers have studied the impact of a warmer climate on the countryside in the north. Until now, the focus has been concentrated on individual species, but an international team of biologists has now published an important study of entire food-web dynamics in the journal Nature Climate Change. Field studies covering three continents show that temperature has an unexpectedly important effect on food-web structure, while the relationship between predator and prey is crucial for the food-web dynamics and thereby the entire ecosystem.Temperature is decisive’We have gathered data on all animals and plants characterising the arctic tundra in seven different areas. This has allowed us to generate a picture of how food chains vary over a very large geographical (and, with it, climatic) gradient. Therefore, and for the first time, we can offer an explanation of the factors governing the tundra as an ecosystem,’ says Niels Martin Schmidt from Aarhus University, Denmark, one of the researchers behind the study. The researchers have evidenced that temperature is of decisive importance for which elements form part of the food chain, thus permitting them to predict how climate changes may impact whole food chains — and not just the conditions for the individual species.The largest avoids being eatenTemperature regulates which organisms interact with each other in the far north arctic nature. However, the present study also shows that predation, i.e. the interactions between predators and prey, is the factor regulating the energy flows in ecosystems and, with that, the function of the ecosystem.’Our results show that predators are the most important items of the tundra food chains, except in the High Arctic. The intensity varies with the body size of the herbivores (plant eaters) of the chains. …

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Ancient sea creatures filtered food like modern whales

Ancient, giant marine animals used bizarre facial appendages to filter food from the ocean, according to new fossils discovered in northern Greenland. The new study, led by the University of Bristol and published today in Nature, describes how the strange species, called Tamisiocaris, used these huge, specialized appendages to filter plankton, similar to the way modern blue whales feed today.The animals lived 520 million years ago during the Early Cambrian, a period known as the ‘Cambrian Explosion’ in which all the major animal groups and complex ecosystems suddenly appeared. Tamisiocaris belongs to a group of animals called anomalocarids, a type of early arthropod that included the largest and some of the most iconic animals of the Cambrian period. They swam using flaps down either side of the body and had large appendages in front of their mouths that they most likely used to capture larger prey, such as trilobites.However, the newly discovered fossils show that those predators also evolved into suspension feeders, their grasping appendages morphing into a filtering apparatus that could be swept like a net through the water, trapping small crustaceans and other organisms as small as half a millimetre in size.The evolutionary trend that led from large, apex predators to gentle, suspension-feeding giants during the highly productive Cambrian period is one that has also taken place several other times throughout Earth’s history, according to lead author Dr Jakob Vinther, a lecturer in macroevolution at the University of Bristol.Dr Vinther said: “These primitive arthropods were, ecologically speaking, the sharks and whales of the Cambrian era. In both sharks and whales, some species evolved into suspension feeders and became gigantic, slow-moving animals that in turn fed on the smallest animals in the water.”In order to fully understand how the Tamisiocaris might have fed, the researchers created a 3D computer animation of the feeding appendage to explore the range of movements it could have made.”Tamisiocaris would have been a sweep net feeder, collecting particles in the fine mesh formed when it curled its appendage up against its mouth,” said Dr Martin Stein of the University of Copenhagen, who created the computer animation. “This is a rare instance when you can actually say something concrete about the feeding ecology of these types of ancient creatures with some confidence.”The discovery also helps highlight just how productive the Cambrian period was, showing how vastly different species of anomalocaridids evolved at that time, and provides further insight into the ecosystems that existed hundreds of millions of years ago.”The fact that large, free-swimming suspension feeders roamed the oceans tells us a lot about the ecosystem,” Dr Vinther said. “Feeding on the smallest particles by filtering them out of the water while actively swimming around requires a lot of energy — and therefore lots of food.”Tamisiocaris is one of many recent discoveries of remarkably diverse anomalocarids found in rocks aged 520 to 480 million years old. “We once thought that anomalocarids were a weird, failed experiment,” said co-author Dr Nicholas Longrich at the University of Bath. “Now we’re finding that they pulled off a major evolutionary explosion, doing everything from acting as top predators to feeding on tiny plankton.”The Tamisiocaris fossils were discovered during a series of recent expeditions led by co-author David Harper, a professor at Durham University. “The expeditions have unearthed a real treasure trove of new fossils in one of the remotest parts of the planet, and there are many new fossil animals still waiting to be described,” he said. …

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Forests crucial to green growth

The value of forests and tree-based ecosystems extends far beyond carbon sequestration; they are the foundation of sustainable societies.A new report, launched in Jakarta, Indonesia on 21 March — the International Day of Forests — promotes REDD+ and the Green Economy as together providing a new pathway to sustainable development that can benefit all nations. It claims this approach can conserve and even boost the economic and social benefits forests provide to human society.Building Natural Capital — How REDD+ Can Support a Green Economy was developed by the International Resources Panel. It outlines how REDD+ can be integrated into a Green Economy to support pro-poor development while maintaining or increasing forest cover.According to the report, REDD+ needs to be placed in a landscape-scale planning framework that goes beyond forests to consider all sectors of a modern economy and the needs of agriculture, energy, water resources, finance, transport, industry, trade and cities.In this way, REDD+ would add value to other initiatives, such as agroforestry projects that are being implemented within these sectors, and be a critical element in a green economy.The report provides recommendations on how to integrate REDD+ and Green Economy approaches, such as through better coordination, stronger private sector engagement, changes in fiscal incentive frameworks, greater focus on assisting policymakers to understand the role forests play in propping up economies, and equitable benefit sharing.While it is recognized that what lies ahead is a long process of societies adapting to new conditions, REDD+ could be integral to increasing agricultural and forestry outputs to meet future needs, while at the same time enhancing the conservation of forests and ecosystem services.Each year, the International Day of Forests highlights the unique role of forests in the environment and in sustaining livelihoods. The theme this year is Celebrating Forests for Sustainable Development.”It is important day to remind us to save our planet as it is the only one we know which has trees says Tony Simons the Director General of the World Agroforestry Centre (ICRAF). “Trees are what made Earth habitable for mammals, and destruction of forests will lead to the ultimate destruction of mammals — including humans. Trees are one of the few things which live longer than humans — a true intergenerational gift. He added.Forests and trees are key to sustainable development. Not only do they store carbon, they support biodiversity, regulate water flows and, reduce soil erosion. Nearly 1.6 billion people worldwide depend on forests as a source of food, medicines, timber and fuel.Story Source:The above story is based on materials provided by World Agroforestry Centre (ICRAF). Note: Materials may be edited for content and length.

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Omnivorous species are more resistant to fire effects

A study published on the journal PLOS ONE demonstrates that omnivorous species are the most resistant to fire.The main authors of the article are researchers Eduardo Mateos, from the Department of Animal Biology of the University of Barcelona (UB), and Xavier Santos, from the Research Centre in Biodiversity and Genetic Resources of the University of Porto. The article is also signed by experts Antoni Serra, from the Department of Animal Biology of UB; Teresa Saura and Ramon Vallejo, from the Department of Plant Biology of UB, and Santiago Sabat, from the Department of Ecology of UB and the Centre for Ecological Research and Forestry Applications (CREAF).The study analyses changes in composition and abundance in 274 species after the fire that happened in August 2003 in Sant Lloren del Munt i l’Obac Natural Park. It was developed within the monitoring of fauna recolonization developed in the burnt area after the fire.After the fireIt is the first time that a study compares different responses of a set of animal organisms to fire (snails, spiders, beetles, ants, grasshoppers, bugs, birds and reptiles). The study also enabled to analyse some causes that could explain species response, for instance dietary and mobility patterns.According to authors, omnivorous species are more resilient to fire probably due to their ability to adapt their dietary habits to available food resources, which vary between burnt and unburnt areas. Surprisingly, the study also demonstrates that high-mobility species — such as birds that move to unburnt areas — and low-mobility species — like snails that cannot hide and die by burning — are the ones that show more changes in composition.Professor Eduardo Mateos affirms that “postfire management practices must consider the strong relationship between animal and plant communities. If the main objective of is to maximize biodiversity, habitat management may provide mosaics to preserve heterogeneity; the study proves that this would be the best management practice.”Even if it seems to go against general opinion, results support the idea that fire may play a critical role for some threatened species, as the elimination of some species enables the appearance of certain species that can be more interesting regarding conservation. This would be the case of snail Xerocrassa montserratensis and Red-legged Partridge Alectoris rufa, two interesting species which appeared after the fire in the area.Other researchers and technicians also collaborated in the study. They belong to several institutions such as the Autonomous University of Barcelona, the University of Girona, the Centre for Ecological Research and Forestry Applications (CREAF), the Forest Sciences Centre of Catalonia (CTFC), the Natural History Museum of Barcelona, the Estacin Experimental de les Zonas ridas, the Mediterranean Centre for Environmental Studies (CEAM), the Oficina Tcnica de Parcs Naturals of the Barcelona Provincial Council and the Directorate General for the Environment and Biodiversity of the Goverment of Catalonia.Story Source:The above story is based on materials provided by Universidad de Barcelona. Note: Materials may be edited for content and length.

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Radiation damage at the root of Chernobyl’s ecosystems

Radiological damage to microbes near the site of the Chernobyl disaster has slowed the decomposition of fallen leaves and other plant matter in the area, according to a study just published in the journal Oecologia. The resulting buildup of dry, loose detritus is a wildfire hazard that poses the threat of spreading radioactivity from the Chernobyl area.Tim Mousseau, a professor of biology and co-director of the Chernobyl and Fukushima Research Initiatives at the University of South Carolina, has done extensive research in the contaminated area surrounding the Chernobyl nuclear facility, which exploded and released large quantities of radioactive compounds in the Ukraine region of the Soviet Union in 1986. He and frequent collaborator Anders Mller of Universit Paris-Sud noticed something unusual in the course of their work in the Red Forest, the most contaminated part of the Chernobyl Exclusion Zone.”We were stepping over all these dead trees on the ground that had been killed by the initial blast,” Mousseau said. “Some 15 or 20 years later, these tree trunks were in pretty good shape. If a tree had fallen in my backyard, it would be sawdust in 10 years or so.”They set out to assess the rate at which plant material decomposed as a function of background radiation, placing hundreds of samples of uncontaminated leaf litter (pine needles and oak, maple and birch leaves) in mesh bags throughout the area. The locations were chosen to cover a range of radiation doses, and the samples were retrieved after nine months outdoors.A statistical analysis of the weight loss of each leaf litter sample after those nine months showed that higher background radiation was associated with less weight loss. The response was proportional to radiation dose, and in the most contaminated regions, the leaf loss was 40 percent less than in control regions in Ukraine with normal background radiation levels.They also measured the thickness of the forest floor in the same areas where samples were placed. They found that it was thicker in places with higher background radiation.The team concluded that the bacteria and fungi that decompose plant matter in healthy ecosystems are hindered by radioactive contamination. They showed a smaller effect for small invertebrates, such as termites, that also contribute to decomposition of plant biomass.According to Mousseau, slower decomposition is likely to indirectly slow plant growth, too, given that the products of decomposition are nutrients for new plants. The team recently reported diminished tree growth near Chernobyl, which he says likely results both from direct radiation effects and indirect effects such as reduced nutrient supply.”It’s another facet of the impacts of low-dose-rate radioactive contaminants on the broader ecosystem,” Mousseau says. …

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