Ants plant tomorrow’s rainforest

Tropical montane rain forests are highly threatened and their remnants are often surrounded by deforested landscapes. For the regeneration of these degraded areas, seed dispersal of forest trees plays a crucial role but is still poorly understood. Most tree species are dispersed by birds and mammals, but also by ants. A study published today in the Journal of Ecology by a team from the LOEWE Biodiversity and Climate Research Centre and the University of Halle-Wittenberg demonstrates the importance of this hitherto neglected ecosystem function for the restoration of montane rain forests. Ants promote the regeneration of these forests by dispersing seeds to safe sites for tree establishment.The Yungas, a region on the eastern slopes of the Bolivian Andes near La Paz, are marked by elongated valleys with relicts of the original mountain rain forest. Due to land-use practices like slash-and-burn agriculture and the extension of coca plantations, the forests are highly fragmented. The forest relicts are surrounded by an open, largely degraded cultural landscape. In this context, the team conducted experiments to find out to what extent ants contribute to the dispersal of a widespread, primarily bird-dispersed tree (Clusia trochiformis) and tested whether this ecosystem function may contribute to the restoration of deforested areas.The red, lipid-rich aril, a fleshy pulp surrounding the seeds of Clusia, is highly attractive to many animals. Birds are the primary dispersers. They feed on the nutritious part of the fruits, the fleshy aril, and defecate the seeds. …

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Plankton make scents for seabirds and a cooler planet

The top predators of the Southern Ocean, far-ranging seabirds, are tied both to the health of the ocean ecosystem and to global climate regulation through a mutual relationship with phytoplankton, according to newly published work from the University of California, Davis.When phytoplankton are eaten by grazing crustaceans called krill, they release a chemical signal that calls in krill-eating birds. At the same time, this chemical signal — dimethyl sulfide, or DMS — forms sulfur compounds in the atmosphere that promote cloud formation and help cool the planet. Seabirds consume the grazers, and fertilize the phytoplankton with iron, which is scarce in the vast Southern Ocean. The work was published March 3 in the Proceedings of the National Academy of Sciences.”The data are really striking,” said Gabrielle Nevitt, professor of neurobiology, physiology and behavior at UC Davis and co-author on the paper with graduate student Matthew Savoca. This suggests that marine top predators are important in climate regulation, although they are mostly left out of climate models, Nevitt said.”In addition to studying how these marine top predators are responding to climate change, our data suggest that more attention should be focused on how ecological systems, themselves, impact climate. Studying DMS as a signal molecule makes the connection,” she said.Nevitt has studied the sense of smell in ocean-going birds for about 25 years, and was the first to demonstrate that marine top predators use climate-regulating chemicals for foraging and navigation over the featureless ocean. DMS is now known to be an important signal for petrels and albatrosses, and the idea has been extended to various species of penguins, seals, sharks, sea turtles, coral reef fishes and possibly baleen whales, she said.Phytoplankton are the plants of the open ocean, absorbing carbon dioxide and sunlight to grow. When these plankton die, they release an enzyme that generates DMS.A role for DMS in regulating climate was proposed by Robert Charlson, James Lovelock, Meinrat Andreae and Stephen Warren in the 1980s. According to the CLAW hypothesis, warming oceans lead to more growth of green phytoplankton, which in turn release a precursor to DMS when they die. Rising levels of DMS in the atmosphere cause cloud formation, and clouds reflect sunlight, helping to cool the planet. …

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Ancient food webs developed modern structure soon after mass extinction

Researchers from the Santa Fe Institute and the Smithsonian Institution have pieced together a highly detailed picture of feeding relationships among 700 mammal, bird, reptile, fish, insect, and plant species from a 48 million year old lake and forest ecosystem.Their analysis of fossilized remains from the Messel deposit near Frankfurt, Germany, provides the most compelling evidence to date that ancient food webs were organized much like modern food webs. Their paper describing the research appears online and open access this week in Proceedings of the Royal Society B: Biological Sciences.The researchers first compiled data about the more than 6,500 feeding relationships among 700 species found in the deposit, which dates to the Eocene epoch. Then they constructed two networks of feeding interactions — one for the lake and one for the surrounding forest.Next, they mathematically compared each food web’s structural features with those of modern-day food web datasets — matching up such indicators as fractions of cannibals, herbivores, and omnivores; the distributions of generalist and specialist feeders; the mean lengths of feeding chains connecting pairs of taxa; and so on.”What we found is that the Messel lake food web, with 94 taxa and 517 links, looks very much like a modern food web,” says SFI Professor Jennifer Dunne. “This is despite the fact that 48 million years of species turnover and evolution separate the Messel lake ecosystem from modern ecosystems.”Analysis of the Messel forest food web’s structure was more challenging due to the high degree of species diversity represented in the Messel dataset — 630 taxa and 5,534 feeding links — far more than what datasets for modern webs include.”Basically, we don’t yet have examples of comprehensive modern terrestrial food web datasets that have the high resolution of plants, insects, and their interactions that we included in the Messel forest dataset,” says Dunne.Nevertheless, the researchers were able to show that the Messel forest web is likely comparable in structure to modern webs, by using models to account for differences in structure that would result from the many more taxa and interactions in the Messel data.The results are significant because they show that the Messel ecosystem developed a modern ecological structure, along with a modern biota, in a relatively brief 18 million year period following Earth’s most recent die-off, the end-Cretaceous mass extinction, which disrupted ecosystem dynamics on a massive scale and served as a species diversity bottleneck.Dunne says that beyond the ecological and evolutionary significance of the study, the work resulted in the most highly resolved, detailed, and comprehensive terrestrial food web ever compiled.”We want our data to serve as a challenge to ecologists to compile more highly and evenly resolved food web data for extant systems,” she says.Ancient food webs are particularly difficult to reconstruct because data about them is usually limited and of low quality. But the Messel shale deposit is unique. Scientists hypothesize that releases of toxic volcanic gases rendered the area’s air and water lethal to most life in a short time. Animals in and near the lake were overwhelmed, and, along with plants, sunk to the low-oxygen depths of the lake where they were smothered in mud and fossilized, soft tissue and all.The Messel includes outstanding evidence of feeding interactions, including stomach contents and bite marks in soft tissues that can be traced back to particular species’ mouth parts, Dunne says.”Compiling such a highly resolved food web was possible for the Messel because of the exquisite preservation of soft body parts and ecological traces in the deposit,” she says, “and because my co-author, Conrad Labandeira, is one of the world’s foremost experts on fossil plant-insect interactions.”Story Source:The above story is based on materials provided by Santa Fe Institute. Note: Materials may be edited for content and length.

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Reintroduction experiments give new hope for plant on brink of extinction

A critically endangered plant known as marsh sandwort (Arenaria paludicola) is inching back from the brink of extinction thanks to the efforts of a UC Santa Cruz plant ecologist and her team of undergraduate students.Ingrid Parker, the Langenheim professor of plant ecology and evolution at UC Santa Cruz, got involved in the marsh sandwort recovery effort at the request of the U.S. Fish and Wildlife Service (USFWS). Although it used to occur all along the west coast, from San Diego to Washington state, this wetland plant with delicate white flowers had dwindled to one population in a boggy wetland in San Luis Obispo County. Federal biologists wanted to reintroduce the plant to other locations, but they weren’t sure where it would be likely to thrive.”When you have a species that’s only known from one place, how do you figure out where it could live? We had very little information about its biology that would allow us to predict where it might be successful,” Parker said.Her team, which included undergraduate students and greenhouse staff at UCSC as well as USFWS biologists, propagated cuttings from the last remaining wild population, studied the plant’s tolerance for different soil conditions in greenhouse experiments, and conducted field experiments to identify habitats where the plant could thrive. They published their findings in the April issue of Plant Ecology (available in advance online).Surprisingly, the plants tolerated a much wider range of soil moisture and salinity than biologists had expected. “This really brought home to me the importance of experiments to help guide conservation,” Parker said. “The one place where this species is found in San Luis Obispo County is a freshwater bog where the plants are in standing water. There are so few places like that left in California, we wondered if that’s the only kind of place where it can grow. Instead we found that it actually does better without standing water.”In addition, field studies showed the importance of small-scale habitat variations, according to first author Megan Bontrager. …

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Preserving large carnivores in ecosystem requires multifaceted approach

Carnivore management is not just a numbers game, Virginia Tech wildlife scientists assert in response to an article in the Jan. 10 issue of the journal Science that urged “minimum population densities be maintained for persistence of large carnivores, biodiversity, and ecosystem structure.””This type of approach may fail in social carnivore species,” said Kathleen Alexander, an associate professor of fisheries and wildlife conservation in the College of Natural Resources and Environment. “Predator management is incredibly complex and we need to be extremely cautious in applying blanket approaches which rely on securing some target number or density of individuals in an ecosystem.”The research-based argument appears in a letter in the March 14 issue of Science and an article abstract in the October 2013 issue of the journal Population Ecology.”Life history strategy, including number of offspring, lifespan, diet, and behavior that evolves from ecological pressures of the species in question should also guide management approaches,” wrote Alexander and Claire E. Sanderson, a postdoctoral associate in fisheries and wildlife conservation, in the Science letter.The research published in Population Ecology evaluated 45 solitary and social medium and large carnivore species and their key life history attributes, population trends, and identified the presence of factors that increase the potential for extinction.Disturbingly, 73 percent of carnivore species — both social and solitary — were declining, observed Sanderson, Sarah Jobbins, also a postdoctoral associate, and Alexander.”Social carnivores appeared to be particularly vulnerable with 45 percent threatened by infectious disease but only 3 percent of solitary carnivores similarly impacted,” they report. “In this, increased contact between individuals, disease-related mortality, and loss of individuals below some critical threshold seems to be the issue, pushing social carnivores closer to the brink of extinction.”Reporting on their research on social carnivores, Sanderson, Jobbins, and Alexander said in the article, “Highly cohesive social species, like African wild dog, require strict participation from all group members … in all areas of life, including predator avoidance, reproductive success, hunting, and survivorship. This life-history strategy can result in enhanced fitness benefits for the group, but also a higher critical threshold for extinction.””The number of individuals in the group then becomes the critical factor influencing population persistence,” said Sanderson.For example, rabies and distemper have caused local extinction of African wild dog in regions of Africa. Even in a large population, transmission of an infectious disease from only a few infected individuals can result in sufficient mortality to push groups below a critical threshold, ultimately threatening population persistence, the researchers report.It has been found in certain ecosystems that when wild dog packs are reduced to less than four individuals, they may be unable to rear pups because of trade-offs between specialized roles, such as pup guarding and hunting.”While aggregation of conspecifics may be beneficial for reproduction, hunting, and vigilance, social living is a disadvantage when it comes to transmission of disease,” according to Alexander’s research.Also a wildlife veterinarian, she cofounded the Centre for Conservation of African Resources: Animals, Communities and Land Use, in Kasane, Botswana and has been conducting research in Africa since the late 1980s.”Failure to consider the impacts of group dynamics may result in underestimation of critical threshold population sizes or densities required for population persistence,” Sanderson, Jobbins, and Alexander write.Alexander and Sanderson conclude in their letter in Science, “We urge consideration of life-history strategy and social behavior in the development of carnivore management strategy.”

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Reindeer grazing may counteract effects of climate warming on tundra carbon sink

Local reindeer grazing history is an important determinant in the response of an ecosystem’s carbon sink to climate warming, say researchers at the Arctic Centre of the University of Lapland. Their study was published in the journal Nature Climate Change on 16 March 2014. The research project has been funded by the Academy of Finland.The consequences of global climate warming on ecosystem carbon sink in tundra are of great interest, because carbon that is currently stored in tundra soils may be released to the atmosphere in a warmer climate. This could contribute to atmospheric carbon dioxide concentration, and thus create a positive feedback that intensifies global change.A major portion of the Arctic is grazed by reindeer. In northernmost Europe, the reindeer was domesticated a few centuries ago. In a field experiment in northern Norway, the effects of experimental warming were compared between lightly and heavily grazed tundra. The grazing history between these areas had varied for the past 50 years. Carbon balances showed that under the current climate, lightly grazed, dwarf-shrub-dominated tundra were a stronger carbon sink than heavily grazed, graminoid-dominated tundra. However, warming decreased the carbon sink in lightly grazed tundra, but had no effect in heavily grazed tundra. Thus, tundra with a long history of intensive grazing showed a weak response to climate warming.The main reason for this grazer-induced difference was that in heavily grazed tundra, graminoids with rapid growth rates were able to increase their photosynthesis and carbon fixation under increased temperatures. …

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Serpentine ecosystems shed light on nature of plant adaptation, speciation

Plants that live in unusual soils, such as those that are extremely low in essential nutrients, provide insight into the mechanisms of adaptation, natural selection, and endemism. A seminal paper by Arthur Kruckeberg from 1951 on serpentine plant endemism has served as a solid bedrock foundation for future research on the link between natural selection and speciation. A recent article in the American Journal of Botany focuses on how this paper has influenced subsequent research on local adaptation, evolutionary pathways, and the relationship between climate, soils, and endemism.In the latest in a series of AJB Centennial Review papers, AJB Anacker (University of California, Davis) examines the impact that Kruckeberg’s 1951 AJB paper has had on our subsequent understanding of plant evolution and ecology.Kruckeberg’s classic paper reported on reciprocal transplant experiments, in which he made several generalizations about plant competition, local adaptation, and speciation. Kruckeberg showed that the strong selective pressures of serpentine soils — characterized by low amounts of essential nutrients and water, and high in heavy metals — can lead to the formation of soil ecotypes (genetically distinct plant varieties), representing a possible first step in the evolution of serpentine endemism (e.g., plants that are only found on serpentine type soils). These important initial findings spurred subsequent research on determining plant traits (from molecular to organismal) that underlie serpentine adaptation.Anacker draws attention to a second significant contribution of Kruckeberg’s paper — researching the historic origins of endemic species, such as those found in serpentine soils. Anacker explains that endemic species are thought to originate in two ways: neoendemics are species that have formed relatively recently via nearby progenitor taxa, and paleoendemics are species that formed following habitat-specific population extirpation. Kruckeberg viewed serpentine ecotypes as representing the first step along the path of paleoendemism. While this stimulated much research in this area, Anacker points out that several serpentine endemics appear to have arisen from nearby progenitor taxa, and thus the neoendemic pathway is also likely important.Interestingly, Kruckeberg’s experiments also showed that many serpentine ecotypes actually performed better on the non-serpentine soils than on serpentine soils, which begs the question of why serpentine-adapted plants are not also found on non-serpentine soils. Anacker points out that Kruckeberg was one of the first to indicate that competition may play a key role in serpentine specialization. He also highlights recent research indicating that serpentine species are typically slow-growing stress tolerators rather than fast-growing competitive dominants, and their adaptations for being more drought-tolerant puts them at a disadvantage in soils where water and nutrients are not limiting.While serpentine ecosystems are special and unique environments, Kruckeberg and subsequent researchers have shown how important these systems are for shedding light on broader aspects of plant ecology and evolution.The 1951 paper can be accessed online at: http://www.jstor.org/discover/10.2307/2438248?uid=3739448&uid=2&uid=3737720&uid=4&sid=21103728973903Story Source:The above story is based on materials provided by American Journal of Botany. …

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A tale of two data sets: New DNA analysis strategy helps researchers cut through the dirt

For soil microbiology, it is the best of times. While no one has undertaken an accurate census, a spoonful of soil holds hundreds of billions of microbial cells, encompassing thousands of species. “It’s one of the most diverse microbial habitats on Earth, yet we know surprisingly little about the identities and functions of the microbes inhabiting soil,” said Jim Tiedje, Distinguished Professor at the Center for Microbial Ecology at Michigan State University. Tiedje, along with MSU colleagues and collaborators from the U.S. Department of Energy Joint Genome Institute (DOE JGI) and Lawrence Berkeley National Laboratory (Berkeley Lab), have published the largest soil DNA sequencing effort to date in the March 10, 2014, issue of Proceedings of the National Academy of Sciences (PNAS). What has emerged in this first of the studies to come from this project is a simple, elegant solution to sifting through the deluge of information gleaned, as well as a sobering reality check on just how hard a challenge these environments will be.”The Great Prairie represents the largest expanse of the world’s most fertile soils, which makes it important as a reference site and for understanding the biological basis and ecosystem services of its microbial community,” said Tiedje. “It sequesters the most carbon of any soil system in the U.S. and produces large amounts of biomass annually, which is key for biofuels, food security, and carbon sequestration. It’s an ecosystem that parallels the large ocean gyres in its importance in the world’s primary productivity and biogeochemical cycles.”Since the release of the first human genome over a decade ago, the applications of DNA sequencing have been extended as a powerful diagnostic technique for gauging the health of the planet’s diverse ecological niches and their responsiveness to change. In this ambitious pilot study launched by the DOE JGI, MSU researchers sought to compare the microbial populations of different soils sampled from Midwestern corn fields, under continuous cultivation for 100 years, with those sourced from pristine expanses of the Great Prairie. …

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Soil microbes shift as shrubs invade remnant hill prairies

Perched high on the bluffs of the big river valleys in the Midwest are some of the last remnants of never-farmed prairie grasslands. These patches, edged by forest, are slowly being taken over by shrubs. A recent University of Illinois study examined the soil microbes on nine patches, also called “balds,” that had varying degrees of shrub invasion and found an interesting shift in the composition of the microbial community.”When we looked at the soil samples from a lightly encroached hill prairie remnant, it was very clear that there was a set of fungi that look like grassland fungi, a set of fungi that look like tree fungi, and the shrubs between the two have some features of both,” said U of I microbial ecologist Tony Yannarell. “As the degree of shrub encroachment increased, the amount of change in the fungal communities also increased, and as the degree of shrub encroachment increased, that shrub fungi joined the forest group to become one big woody community.”Yannarell said that on the balds that were completely encroached, the soil samples across the entire remnant were the same. “You get this shift toward woody fungal communities that mirror how much shrub density you have in the hill prairie,” he said.Yannarell said that forest and prairie microbial communities are always very different from each other even in this case where they are only a couple of meters apart. And because of the close proximity, with the same overall climate conditions and soil origin, they could rule out a lot of factors that would normally affect a change in microbial community structure.The microbes in the shrub soil tend to be different, but different parts of the microbial community change in relationship to the shrub, to the forest, to the prairie. The shrub bacteria are more like what they found in open prairie than in the forest. But the shrub fungi looked a lot more like the forest fungi.”We think what we found is the signature of these early changes, these early shifts of microbial communities toward a woody fungal community,” Yannarell said. “This first study only reveals one side of the change. We think we can firmly conclude that there are some woody, plant-liking fungi. …

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Fish species unique to Hawaii dominate deep coral reefs in Northwestern Hawaiian Islands

Deep coral reefs in Papahanaumokuakea Marine National Monument (PMNM) may contain the highest percentage of fish species found nowhere else on Earth, according to a study by NOAA scientists published in the Bulletin of Marine Science. Part of the largest protected area in the United States, the islands, atolls and submerged habitats of the Northwestern Hawaiian Islands (NWHI) harbor unprecedented levels of biological diversity, underscoring the value in protecting this area, scientists said.Hawaii is known for its high abundance of endemic species — that is, species not found anywhere else on Earth. Previous studies, based on scuba surveys in water less than 100 feet, determined that on average 21 percent of coral reef fish species in Hawaii are unique to the Hawaiian Archipelago.However, in waters 100 to 300 feet deep, nearly 50 percent of the fish scientists observed over a two-year period in the monument were unique to Hawaii, a level higher than any other marine ecosystem in the world. The study also found that on some of PMNM’s deeper reefs, more than 90 percent of fish were unique to the region. These habitats can only be accessed by highly trained divers using advanced technical diving methods.”The richness of unique species in the NWHI validates the need to protect this area with the highest conservation measures available,” said Randy Kosaki, PMNM’s deputy superintendent and co-author of the study. “These findings also highlight the need for further survey work on the monument’s deeper reefs, ecosystems that remain largely unexplored.”Data for the study was collected during two research expeditions to the NWHI aboard NOAA Ship Hi’ialakai in the summers of 2010 and 2012. Some of the unique fish species that were observed include: Redtail Wrasse (Anampses chrysocephalus), Thompson’s Anthias (Pseudanthias thompsoni), Potter’s Angelfish (Centropyge potteri), Hawaiian Squirrelfish (Sargocentron xantherythrum), Chocolate Dip Chromis (Chromis hanui), Masked Angelfish (Genicanthus personatus), and Blueline Butterflyfish (Chaetodon fremblii).Story Source:The above story is based on materials provided by NOAA Headquarters. Note: Materials may be edited for content and length.

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Land cover change over five years across North America revealed

A new set of maps featured in the CEC’s North American Environmental Atlas depicts land cover changes in North America’s forests, prairies, deserts and cities, using satellite images from 2005 and 2010. These changes can be attributed to forest fires, insect infestation, urban sprawl and other natural or human-caused events. Produced by the North American Land Change Monitoring System (NALCMS), a trinational collaborative effort facilitated by the CEC, these maps and accompanying data can be used to address issues such as climate change, carbon sequestration, biodiversity loss, and changes in ecosystem structure and function.This project, which seeks to address land cover change at a North American scale, was initiated at the 2006 Land Cover Summit, in Washington, DC. Since then, specialists from government agencies in Canada, Mexico and the United States have worked together to harmonize their land cover classification systems into 19 classes that provide a uniform view of the continent at a consistent 250-meter scale.To view examples of significant land cover changes in British Colombia, California, and Cancun, slide the green bars on the maps, found at: www.cec.org/nalcms.To view the full 2005-2010 land cover change map, visit www.cec.org/atlas and click on “Terrestrial Ecosystems” on the left. Under “Land Cover,” click on the plus sign next to “2005-2010 land cover change” to add the map layer to North America. Then zoom in and take a look at all the purple patches — these are the areas of North America where land cover has changed over the five-year period.North American Land Change Monitoring SystemNALCMS is a joint project between Natural Resources Canada/Canada Centre for Mapping and Earth Observation (NRCan/CCMEO), the United States Geological Survey (USGS), and three Mexican organizations: the National Institute of Statistics and Geography (Instituto Nacional de Estadstica y Geografa — Inegi), the National Commission for the Knowledge and Use of Biodiversity (Comisin Nacional para el Conocimiento y Uso de la Biodiversidad — Conabio), and the National Forestry Commission of Mexico (Comisin Nacional Forestal — Conafor), supported by the Commission for Environmental Cooperation (CEC).The North American Environmental AtlasThe North American Environmental Atlas brings together maps, data and interactive map layers that can be used to identify priority areas to conserve biodiversity, track cross-border transfers of pollutants, monitor CO2 emissions across major transportation routes and predict the spread of invasive species. Land Cover 2010 and Land Cover Change 2005-2010 are the latest in a series of maps that harmonize geographic information across North America’s political boundaries to depict significant environmental issues at a continental scale.Story Source:The above story is based on materials provided by Commission for Environmental Cooperation. Note: Materials may be edited for content and length.

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Dingo poisoning should be stopped to protect native Australian mammals

Poisoning of dingoes — the top predators in the Australian bush — has a deleterious effect on small native mammals such as marsupial mice, bandicoots and native rodents, a UNSW-led study shows.The research, in forested National Parks in NSW, found that loss of dingoes after baiting is associated with greater activity by foxes, which prey on small marsupials and native rodents.As well, the number of kangaroos and wallabies increases when dingoes, also known as wild dogs, disappear. Grazing by these herbivores reduces the density of the understorey vegetation in which the small ground-dwelling mammals live.”Dingoes should not be poisoned if we want to halt the loss of mammal biodiversity in Australia. We need to develop strategies to maintain the balance of nature by keeping dingoes in the bush, while minimising their impacts on livestock,” says the senior author, UNSW’s Dr Mike Letnic.The study is published in the journal Proceedings of the Royal Society B.The researchers surveyed seven pairs of forested sites within conservation reserves managed by the NSW National Parks and Wildlife Service.Baiting of dingoes with 1080 poison had been carried out at one location in each pair, but not the other. Apart from the resulting difference in the number of dingoes present, the pairs of locations had similar eucalypt coverage, geology and landforms, and were less than 50 kilometres apart.”This provided an extraordinary natural experiment to compare the impact of the loss of dingoes on a forested ecosystem,” says Dr Letnic, an ARC Future Fellow in the Centre for Ecosystem Science in the UNSW School of Biological, Earth and Environmental Sciences.It is the first study to show how removing large carnivores can result in simultaneous population outbreaks of herbivores and smaller predators. And that these population outbreaks, in turn, can have deleterious effects on smaller mammals.The activity of dingoes, foxes, feral cats and bandicoots was assessed from their tracks. Kangaroos and wallabies and possums were counted from the back of a four wheel drive. Traps were used to catch marsupials and native rodents, and surveys of vegetation were carried out.”We found foxes and large herbivores benefit from dingo control, while small-bodied terrestrial mammal species decline in abundance,” says Dr Letnic.”Predation by foxes is one of the most important threats to small native mammals, and grazing by herbivores can reduce their preferred habitats for shelter, leaving them exposed to predators.”The study’s findings in the forested areas are consistent with the effects of dingo removal in desert areas of Australia.”Actively maintaining dingo populations, or restoring them in areas where they have been exterminated, is controversial but could mitigate the impacts of foxes and herbivores,” says Dr Letnic.”Poisoning of dingoes is counter-productive for biodiversity conservation, because it results in increases in fox activity and declines of small ground-dwelling native mammals.”Story Source:The above story is based on materials provided by University of New South Wales. Note: Materials may be edited for content and length.

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Tropical grassy ecosystems under threat, scientists warn

Scientists at the University of Liverpool have found that tropical grassy areas, which play a critical role in the world’s ecology, are under threat as a result of ineffective management.According to research, published in Trends in Ecology and Evolution, they are often misclassified and this leads to degradation of the land which has a detrimental effect on the plants and animals that are indigenous to these areas.Greater area than tropical rain forestsTropical grassy areas cover a greater area than tropical rain forests, support about one fifth of the world’s population and are critically important to global carbon and energy cycles, and yet do not attract the interest levels that tropical rainforests do.They are characterised by a continuous grass understorey, widespread shade-intolerant plants and the prevalence of fire, which all generate a unique and complex set of ecological processes and interactions not found in other habitats.Dr Kate Parr, from the School of Environmental Sciences, said: “The distinctive evolutionary histories and biodiversity values of these areas needs to be recognised by conservation managers and policy makers.”Whilst it is generally assumed that ‘more trees are better’ in tropical rainforest this is not necessarily the case for tropical grassy ecosystems and so the outcomes of global carbon and conservation initiatives, which include the UN’s Clean Development Mechanism and its Reducing Emissions and Deforestation Forest Degradation schemes, need to be better considered when they are applied to tropical grasslands.”Any changes to the balance between human livelihoods and ecosystem function would have an impact on the use of land, the availability of resources and would affect the way the land functions including its climate.”The vast extent of tropical grasslands and the reliance of human welfare on them means that they deserve far more research and conservation attention than they currently receive.”Grazing, fuel and foodApproximately 20% of the world’s population depend on these areas of land for their livelihoods including their use for grazing, fuel and food. They also store about 15% of the world’s carbon.Tropical grassy ecosystems are associated with savannas and upland grasslands in Africa and savanna-type grasslands in India, Australia, and South America, representing diverse lands from open grassland through to densely canopied savanna.Story Source:The above story is based on materials provided by University of Liverpool. Note: Materials may be edited for content and length.

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New fossil find: Precursor of European rhinos found in Vietnam

A team of scientists from the University of Tbingen and the Senckenberg Center for Human Evolution and Palaeoenvironment Tbingen was able to recover fossils of two previously unknown mammal species that lived about 37 million years ago. The newly described mammals show a surprisingly close relationship to prehistoric species known from fossil sites in Europe. The location: The open lignite-mining Na Duong in Vietnam. Here, the team of scientists was also able to make a series of further discoveries, including three species of fossilized crocodiles and several new turtles.Southeast Asia is considered a particularly species-rich region, even in prehistoric times — a so-called hotspot of biodiversity. For several decades now, scientists have postulated close relationships that existed in the late Eocene (ca. 38-34 million years ago) between the faunas of that region and Europe. The recent findings by the research team under leadership of Prof. Dr. Madelaine Bhme serve as proof that some European species originated in Southeast Asia.Rhinoceros and Coal beastOne of the newly described mammals is a rhinoceros, Epiaceratherium naduongense. The anatomy of the fossil teeth allows identifying this rhinoceros as a potential forest dweller. …

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National U.S. study reveals how urban lawn care habits vary

What do people living in Boston, Baltimore, Miami, Minneapolis-St. Paul, Phoenix, and Los Angeles have in common? From coast to coast, prairie to desert — residential lawns reign.But, according to a new study in the Proceedings of the National Academy of Sciences, beneath this sea of green lie unexpected differences in fertilization and irrigation practices. Understanding urban lawn care is vital to sustainability planning, more than 80% of Americans live in cities and their suburbs, and these numbers continue to grow.The study was undertaken to test “the homogenization hypothesis.” Peter Groffman, a scientist at the Cary Institute of Ecosystem Studies and one of the paper’s authors explains, “Neighborhoods in very different parts of the country look remarkably alike, from lawns and roads to water features. This study is the first to test if urbanization produces similar land management behaviors, independent of the local environment.”Some 9,500 residents in the six study cities were queried about their lawn care habits. The research team, led by Colin Polsky of Clark University and colleagues at 10 other institutions, took into account differences in climate and neighborhood socioeconomics, both within and between cities. A focus was put on fertilization and irrigation, practices with potentially hefty environmental price tags.Fertilizer is rich in nitrogen and phosphorus. This stimulates lawn growth, but when fertilizer washes into waterways, it causes algal blooms that degrade water quality and rob oxygen from fish and other aquatic life. According to the Environmental Protection Agency, landscape irrigation accounts for nearly one-third of residential water use nationwide.Some 79% of surveyed residents watered their lawns and 64% applied fertilizer. Groffman comments, “These numbers are important when we bear in mind that lawns cover more land in the United States than any other irrigated crop. …

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Can the solution to climate change help eliminate poverty?

It is clear that climate change and poverty are two separate problems that affect all corners of the world, but can the solution to one help eliminate the other? Richard Munang and Jessica Andrews, authors of “Harnessing Ecosystem-Based Adaptation: To Address the Social Dimensions of Climate Change,” published in Environment: Science and Policy for Sustainable Development, think that we can.Ecosystem-Based Adaptation (EbA) is becoming more widely recognized as a possible solution to addressing climate change. “EbA is the use of biodiversity and ecosystem services as part of an overall adaptation to help people and communities adapt to the negative effects of climate change at local, regional, and global levels.” It works by providing sustainable social benefits for a local community within climate change adaptation practices. This idea understands the relationship and interconnectivity between many different facets of life; ecological, social/cultural, economic, and institutional.EbA is built to successfully implement sustained social and environmental achievements. Developing a community’s resilience in the face of climate change impacts improves the wellness of the entire ecosystem. “EbA can accelerate income gains, improve health, and secure food production, all while ensuring the sustainable development of local resources.” Munang and Andrews provide examples where this program has been successful. In Togo, Africa, EbA aided in the revitalization of water reservoirs, as well as cereal and vegetable production in the savannah region, directly benefiting women and youth groups. The extraordinary and integral component of this program is the collaboration between nongovernmental and civil society organizations (NGOs and CSOs, respectively) and the local community. This resulted in improved access to water, an array of social benefits, and a trained community competent to take an active role in future resilience efforts.However, there are some problems. The success of EbA depends largely on the involvement of the local community in the planning and implementation process, while also taking into consideration the overall political context and land use conflicts. …

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Deer proliferation disrupts a forest’s natural growth

By literally looking below the surface and digging up the dirt, Cornell researchers have discovered that a burgeoning deer population forever alters the progression of a forest’s natural future by creating environmental havoc in the soil and disrupting the soil’s natural seed banks.The study, “Deer Browsing Delays Succession by Altering Aboveground Vegetation and Belowground Seed Banks,” was published online March 7 in PLOS ONE.”Deer are slowing down forest succession or natural establishment. In fact, the deer are preventing forests from establishing,” says Anurag Agrawal, Cornell professor of ecology and evolutionary biology, a co-author on the paper.Deer typically prefer to eat native, woody plants and rebuff invasive species. The study showed that when deer consume native plants, the non-native species are left to flourish, dropping seed in the soil.As forests normally mature, their grasses give way to herbs and shrubs, and then new trees eventually take root. Expanding deer populations in the Northeast, however, stall forest development and promote the growth of thorny thickets of buckthorn, viburnum and multiflora rose bushes. If deer leave the forests alone, such trees as cottonwood, locust and sumac can sprout and grow unimpeded.The researchers found that the impacts of deer grazing on vegetation were severe and resulted in bare soil and reduced plant biomass, less recruitment of woody species and relatively fewer native species. And the deer’s negative impact on seed banks resulted in significantly decreased overall species richness and relatively more short-lived species of both annual and biennial plants.Co-author Antonio DiTommaso, Cornell associate professor of weed ecology and management, and research technician Scott Morris gathered soil cores — from both within and outside of fenced “deer exclosures” — and germinated the seed. They found the soil cores from outside of the exclosures contained many more seeds from non-native species.Deer select forests for their trees but in doing so disrupt forest system growth trajectories, concludes the study.”It’s obvious that the deer are affecting the above-ground species, but it’s like an iceberg. There are major effects below the soil surface. We are seeing a divergence of seeds contained within the soil from what should be there,” says DiTommaso. “We are not seeing the seeds of woody plants. …

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Deer feeding puts birds at risk, research shows

By comparing the fate of artificial nests close and far away from supplementary feeding sites located in the forest for ungulates, such as deer and wild boar, researchers found that those nests in the vicinity of feeding sites were depredated twice more. This “predation hotspot” effect extends far away from the feeding site itself: in a radius of 1-km the probability of nest survival is lowered. When accounting for all feeding sites in the study region (ca 2000 km2), this would mean that in one fifth of the area ground-nesting birds will have little chance to see their eggs hatching.These sites attract not only deer and wild boar — the boar is also a nest predator — but also corvids, rodents, bears and other species of nest predators, which are not the target of feeding. Therefore, this management practice, widespread in central Europe, comes into conflict with the conservation of ground-nesting birds, such as grouse species, which are declining worldwide.The study was conducted by researchers of the Institute of Nature Conservation of the Polish Academy of Sciences in the Carpathian Mountains, where this practice is deeply-rooted and increasing. “Hundreds of tons of food are thrown every year in the forest, without thinking on the collateral effects and potential consequences,” said Nuria Selva, leader of a project funded by the National Science Centre to investigate the ecological effects of supplementary feeding. The study recommends to avoid ungulate feeding in the breeding areas of bird species of conservation concern, such as capercaillie or black grouse, and to stop feeding before the bird nesting season starts. “We urge for sensible feeding practices and for taking a wider ecosystem perspective, rather than focusing on single issues or species” said Teresa Berezowska-Cnota, co-author of the study.”All our actions in the environment have some effects, and providing food is not an exception. The spread of diseases, for instance, is one of the reasons why deer feeding has been banned in many regions of North America. While supplementary feeding of wildlife is becoming increasingly common in conservation, management and ecotourism, our understanding of the complex effects of providing artificial food to wildlife is still limited,” commented Selva.The study is published in PLOS ONE.Story Source:The above story is based on materials provided by Institute of Nature Conservation of the Polish Academy of Sciences. Note: Materials may be edited for content and length.

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Study suggests non-uniform climate warming globally

A recent University of Oklahoma study of five decades of satellite data, model simulations and in situ observations suggests the impact of seasonal diurnal or daily warming varies between global regions affecting many ecosystem functions and services, such as food production, carbon sequestration and climate regulation. The effects of non-uniform climate warming on terrestrial ecosystems is a key challenge in carbon cycle research and for those making future predictions.Jianyang Xia, a research associate in the OU College of Arts and Sciences, says the impact of non-uniform warming is just one aspect of climate change. Shifts in precipitation and disturbances, such as wildfires, increases in the frequency of extreme temperature events, large year-to-year shifts in temperature and shifts in regional climate zones can be expected as the climate warms. A complete understanding of the consequences of climate change for carbon cycling on land requires insight into the impact of all these changes on the ecosystem.As this study suggests, the rate of climate warming varies by season and region, and between day and night. A synthesis of air temperature data from across the world reveals a greater rate of warming in winter than in summer in northern and high latitudes, but the inverse is true in some tropical regions.Also, the data show a decline in the daily temperature range over 51 percent of the globe and an increase over only 13 percent, because night-time temperatures in most locations have risen faster than daytime temperatures.From the data analyzed, a number of trends emerged in non-uniform climate warming for ecosystem carbon cycling. Spring warming will enhance ecosystem carbon uptake at high latitudes and diminish the magnitude of seasonal temperature change in these regions. Summer and autumn warming are more likely to reduce ecosystem carbon uptake in tropical ecosystems and amplify the magnitude of seasonal temperature change.The contrasting impacts of day- and night-time warming on plant carbon gain and loss are apparent in many regions. Day warming increases carbon uptake in most areas of tundra and boreal forests but decreases it in most grasslands and deserts. Night warming enhances carbon uptake in arid ecosystems, such as grassland desert but has negative impacts in other regions.Most of the existing temperature-manipulation experiments relied on continuous and uniform warming, so further research is needed to predict the effects of non-uniform climate warming on terrestrial carbon cycling. A paper on this study was accepted for early online publication on February 23, 2014, by Nature Geoscience.Story Source:The above story is based on materials provided by University of Oklahoma. …

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Importance of nutrients for coral reefs highlighted by scientists

A new publication from researchers at the University of Southampton and the National Oceanography Centre, Southampton highlights the importance of nutrients for coral reef survival.Despite the comparably small footprint they take on the ocean floor, tropical coral reefs are home to a substantial part of all marine life forms. Coral reefs also provide numerous benefits for human populations, providing food for millions and protecting coastal areas from erosion. Moreover, they are a treasure chest of potential pharmaceuticals and coral reef tourism provides recreation and income for many.Unfortunately, coral reefs are declining at an alarming rate. To promote management activities that can help coral reef survival, an international group of world renowned scientists have summarized the present knowledge about the challenges that coral reefs are facing now and in the future in a special issue of the journal Current Opinion in Environmental Sustainability. The contribution of scientists from the University of Southampton to this special issue highlights the crucial role of nutrients for the functioning of coral reefs.The University of Southampton researchers who are based at the Coral Reef Laboratory in the National Oceanography Centre, Southampton, explain that “too many” nutrients can be as bad for corals as “not enough.”Dr Jrg Wiedenmann, Professor of Biological Oceanography at the University of Southampton and Head of the Coral Reef Laboratory, says: “The nutrient biology of coral reefs is immensely complex. It is important to distinguish between the different direct and indirect effects that a disturbance of the natural nutrient environment can have on a coral reef ecosystem.”Since corals live in a symbiotic relationship with microscopically small plant cells, they require certain amounts of nutrients as “fertiliser.” In fact, the experimental addition of nutrients can promote coral growth. “One should not conclude from such findings, however, that nutrient enrichment is beneficial for coral reefs — usually the opposite is true,” explains Dr Cecilia D’Angelo, Senior Research Fellow in the Coral Reef Laboratory and co-author on the article.Dr Wiedenmann, whose research on coral reef nutrient biology is supported by one of the Starting Grants from the European Research Commission, adds: “Too many nutrients harm corals in many different ways, easily outweighing the positive effects that they can undoubtedly have for the coral-alga association.Paradoxically, the initial addition of nutrients to the water column might result in nutrient starvation of the corals at a later stage. In this publication, we conceptualise the important role that the competition for nutrients by phytoplankton, the free-living relatives of the corals’ symbiotic algae, may have in this context.””Nutrient pollution will continue to increase in many coral reefs. Therefore, an important prerequisite to develop efficient management strategies is a profound understanding of the different mechanisms by which corals suffer from nutrient stress.”Story Source:The above story is based on materials provided by University of Southampton. Note: Materials may be edited for content and length.

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