March 21 marks World Water Day — and a fitting time to consider one of the most unique mammals in Earth’s waters.The nerpa, also known as the Baikal seal, is the only seal that lives exclusively in fresh water. This earless seal can be found in just one place, Russia’s Lake Baikal, where it is at the top of the food web. And now, Wellesley scientists have found that the teeth of this particular seal may hold the strongest evidence of the effects of decades of environmental pollution, nuclear testing, and climate change on Lake Baikal — the deepest, oldest, and most bio-diverse lake in the world.”The Baikal seal teeth are a chemical record of the lake,” said Marianne Moore, Wellesley Professor of Biological Sciences. By analyzing the chemical composition of hundreds of seal teeth, Professor Moore and her co-researchers, post-doctoral fellow Ted Ozersky and Wellesley student Xiu Ying (Annie) Deng ’15, are working to reconstruct the Baikal seal’s diet and contaminant burdens over the last 80 years. The teeth were collected from ice harvested in the area by fellow scientists in Russia.Baikal seals can live up to 40 and 50 years, and much like the rings of a tree trunk, the layers of dentine within their teeth can be studied and linked to environmental patterns and changes over a period of time. Moore, Ozersky, and Deng are looking for evidence of toxic metals such as uranium, mercury, cadmium, and zinc inside the teeth samples, which date back to the period before industrialization in the region.Why not just measure these toxic elements in the water? Professor Moore explained that these metals show up at extremely low levels in the water. The teeth of the nerpa are actually better indicators due to biomagnification, the process by which the concentration of a substance increases with each level of the food chain. Because the Baikal seal is at the top of its food web, their teeth hold the best clues into the lake’s environmental past.”Ultimately, the goal of our project is to study contamination levels in Lake Baikal as reflected by the seals, and to tie these patterns to changes in the watershed, such as the introduction of mining in the area, an increase in coal burning, and other environmental events,” said Dr. Ozersky.Still early in the project, the Wellesley researchers have already made a surprising discovery: levels of some toxic metals such as uranium were higher in the mid 1970’s than in seals today. …Read more
Members of the German research network BIOACID (Biological Impacts of Ocean Acidification) are developing a model that links ecosystem changes triggered by ocean acidification and climate change with their economic and societal consequences. Workshops and interviews with stakeholders from the Norwegian fishing industry and tourism sector, the government and environmental organisations help them to identify key aspects for their assessment.During the past ten years, scientists have learned a lot about the effects of ocean acidification on marine ecosystems. It has become obvious that with rising carbon dioxide emissions from human activities, oceans absorb larger amounts of this greenhouse gas and become more acidic. The increase of acidity, rising water temperatures and other stressors may alter marine ecosystems dramatically — with consequences for economy and society.Do stakeholders of the economic sectors which depend on the sea already observe signs of ocean change? Which are their most urgent questions towards science? Within the framework of the German research network BIOACID (Biological Impacts of Ocean Acidification), scientists from the University of Bremen investigated stakeholders’ state of knowledge and identified focal points for further research. Between March and November 2013, they held workshops and interviewed more than 30 Norwegian fishers, representatives from fishing associations, aquaculture, tourism, environmental organisations and governmental agencies. They aim to develop a model that yields insights into the overall impacts of ocean change for ecosystems and the services they provide to human societies.”Taking a systems view can help to analyse socio-economic impacts of ocean acidification and find ways to mitigate them and adapt to them,” Dr. Stefan Gling-Reisemann, researcher at the Sustainability Research Center (artec) at the University of Bremen explains. “This is why we connect stakeholders and scientists and adapt further research to the demands of society.” Norway was chosen because the fishing industry, a branch that is likely to be hit first by effects of climate change, plays a very important economic role there. …Read more
According to an international team of researchers, the rapid pace of climate change is threatening the future presence of fish near the equator.”Our studies found that one species of fish could not even survive in water just three degrees Celsius warmer than what it lives in now,” says the lead author of the study, Dr Jodie Rummer from the ARC Centre of Excellence for Coral Reef Studies (Coral CoE) at James Cook University.Dr Rummer and her colleagues studied six common species of fish living on coral reefs near the equator. She says many species in this region only experience a very narrow range of temperatures over their entire lives, and so are likely adapted to perform best at those temperatures.This means climate change places equatorial marine species most at risk, as oceans are projected to warm by two to three degrees Celsius by the end of this century.”Such an increase in warming leads to a loss of performance,” Dr Rummer explains. “Already, we found four species of fish are living at or above the temperatures at which they function best.”The team measured the rates at which fish use oxygen, the fuel for metabolism, across different temperatures — at rest and during maximal performance. According to the results, at warmer temperatures fish lose scope for performance. In the wild, this would limit activities crucial to survival, such as evading predators, finding food, and generating sufficient energy to breed.Because many of Earth’s equatorial populations are now living close to their thermal limits, there are dire consequences ahead if these fish cannot adapt to the pace at which oceans are warming.Dr Rummer suggests there will be declines in fish populations as species may move away from the equator to find refuge in areas with more forgiving temperatures.”This will have a substantial impact on the human societies that depend on these fish,” she says.A concentration of developing countries lies in the equatorial zone, where fish are crucial to the livelihoods and survival of millions of people, including those in Papua New Guinea and Indonesia.In an era of rapid climate change, understanding the link between an organism and its environment is crucial to developing management strategies for the conservation of marine biodiversity and the sustainable use of marine fisheries.”This is particularly urgent when considering food security for human communities.”Story Source:The above story is based on materials provided by ARC Centre of Excellence in Coral Reef Studies. Note: Materials may be edited for content and length.Read more
A team of Woods Hole Research Center (WHRC) scientists created maps of habitat corridors connecting protected areas in the tropics to incorporate biodiversity co-benefits into climate change mitigation strategies. Drs. Patrick Jantz, Scott Goetz, and Nadine Laporte describe their findings in an article entitled, “Carbon stock corridors to mitigate climate change and promote biodiversity in the tropics,” available online in the journal Nature Climate Change on January 26.Climate change and deforestation are changing tropical ecosystems, isolating organisms in protected areas that will change along with climate, threatening their survival. Nearly every animal and plant species requires travelling some distance for nutrition, reproduction and genetic diversity, but few conservation or climate mitigation strategies take the connections between conserved lands into account. These habitat corridors are essential for longer-term biodiversity conservation, while also providing opportunities for climate change mitigation in the form of carbon sequestration and avoiding emissions from deforestation.According to lead author Dr. Jantz, “Maintaining connectivity of forest ecosystems provides ecological and societal benefits ensuring long-term species survival and providing room for ecosystems to reorganize in response to climate change and protecting ecosystem services that people depend on.” Co-author Dr. Goetz sees corridors as “avenues for migration of flora and fauna” needed for their survival “under the climate change we’re already committed to.”The team used a high-resolution data set of vegetation carbon stock (VCS) to map 16,257 corridors through areas of the highest biomass between 5,600 protected areas in the tropics. For Dr. Jantz, “the VCS corridor approach informs global frameworks for land management based climate change mitigation by showing which forests contain significant carbon stocks and are important for tropical biodiversity.”Part of the study focused on the Legal Amazon, where the team used economic and biological information combining species richness and endemism with economic opportunity costs and deforestation threats to prioritize optimal corridors. For Dr. …Read more
Sep. 5, 2013 — Scientists at the Zoological Society of London (ZSL) have devised a novel method to identify suitable new homes for animals under threat from climate change.Conservation scientists used their knowledge on species ecology to create habitat suitability maps and correctly identify sites that will remain viable in the future regardless of changing climate. However, the key for success is to understand, and account for, the link between variation in species population size, climate and how the climate may change.Almost half of all bird and amphibian species are believed to be highly vulnerable to extinction from climate change. Species in extreme or rare habitats such as the emperor penguin in the Antarctic and American pika in the USA have already experienced drastic declines in populations due to the impact of climate change on their home.As climate changes, many species will need to move to a different location in order to survive. For species that aren’t able to do this naturally, the only chance of survival is a helping hand through the use of translocations.The research is published today (6 September) in the Journal of Applied Ecology.Dr Nathalie Pettorelli, ZSL’s climate change coordinator and senior author on the paper, says: “Climate change poses a worrying threat to many animals, and relocating vulnerable species to new and more suitable habitats may be the only way to protect them. However, this is an extreme conservation action, which needs to be thoroughly justified, and requires clear guidance on where threatened populations should be moved. Our research shows how these key requirements can be met.”The team used the hihi bird as an example because of the conservation success which came after efforts put into its relocation since the 1980s. Yet, despite large investments into its protection, climate change is now posing a significant threat to its future survival.Dr Alienor Chauvenet, lead author of the study, says: “All current hihi populations are surrounded by either a large stretch of water or unsuitable habitat such as farmland or cities with plenty of non-native predators. This isolation makes it very perilous for them to move and individuals attempting to relocate naturally are unlikely to survive.”Our work shows that assisted colonisation may be the only way to guarantee the survival of this unique species under climate change,” Dr Chauvenet added.Translocations will continue to be an important part of conservation as climate changes. ZSL’s novel method shows how these interventions can be planned to be successful even under the influence of a changing environment. …Read more
Sep. 5, 2013 — Coral reefs are tremendously important for ocean biodiversity, as well as for the economic and aesthetic value they provide to their surrounding communities. Unfortunately they have been in great decline in recent years, much of it due to the effects of global climate change. One such effect, called bleaching, occurs when the symbiotic algae that are essential for providing nutrients to the coral either lose their identifying photosynthetic pigmentation and their ability to perform photosynthesis or disappear entirely from the coral’s tissue. Without a healthy population of these algae, the coral cannot survive.There has been much attention given to the environmental conditions that trigger a reef’s demise due to bleaching, but little is certain about the precise cellular and molecular mechanisms of the bleaching process. New research from Carnegie’s Arthur Grossman brings into question the prevailing theory for how bleaching occurs on a molecular level. It is published in Current Biology.Photosynthesis, the process by which plants, algae, and select bacteria convert the sun’s light energy into chemical energy, takes place in a cellular organelle called the chloroplast. It has been theorized that the major cause of bleaching is the result of chloroplast damage due to heat stress, which results in the production of toxic, highly reactive oxygen molecules during photosynthesis.Grossman and his team — led by Carnegie’s Dimitri Tolleter and in collaboration with John Pringle and Steve Palumbi of Stanford University — demonstrated that bleaching still occurs if the algae are heat stressed in the dark, when the photosynthetic machinery is shut off. This is surprising since it means that toxic oxygen molecules formed in heat-damaged chloroplasts during photosynthetic reactions during the light are likely not the major culprits that cause bleaching.Therefore other, as yet unexplored, mechanisms for bleaching must exist. This work suggests the existence of potentially novel mechanisms associated with coral bleaching. …Read more
Aug. 28, 2013 — The world’s largest ice sheet could be more vulnerable to the effects of climate change than previously thought, according to new research from Durham University.A team from the Department of Geography used declassified spy satellite imagery to create the first long-term record of changes in the terminus of outlet glaciers — where they meet the sea — along 5,400km of the East Antarctic Ice Sheet’s coastline. The imagery covered almost half a century from 1963 to 2012.Using measurements from 175 glaciers, the researchers were able to show that the glaciers underwent rapid and synchronised periods of advance and retreat which coincided with cooling and warming.The researchers said this suggested that large parts of the ice sheet, which reaches thicknesses of more than 4km, could be more susceptible to changes in air temperatures and sea-ice than was originally believed.Current scientific opinion suggests that glaciers in East Antarctica are at less risk from climate change than areas such as Greenland or West Antarctica due to its extremely cold temperatures which can fall below minus 30°C at the coast, and much colder further inland.But the Durham team said there was now an urgent need to understand the vulnerability of the East Antarctic Ice Sheet, which holds the vast majority of the world’s ice and enough to raise global sea levels by over 50m.Dr Chris Stokes, in Durham’s Department of Geography, said: “We know that these large glaciers undergo cycles of advance and retreat that are triggered by large icebergs breaking off at the terminus, but this can happen independently from climate change.”It was a big surprise therefore to see rapid and synchronous changes in advance and retreat, but it made perfect sense when we looked at the climate and sea-ice data.”When it was warm and the sea-ice decreased, most glaciers retreated, but when it was cooler and the sea ice increased, the glaciers advanced.”In many ways, these measurements of terminus change are like canaries in a mine — they don’t give us all the information we would like, but they are worth taking notice of.”The researchers found that despite large fluctuations in terminus positions between glaciers — linked to their size — three significant patterns emerged:In the 1970s and 80s, temperatures were rising and most glaciers retreated; During the 1990s, temperatures decreased and most glaciers advanced; And the 2000s saw temperatures increase and then decrease, leading to a more even mix of retreat and advance. Trends in temperature and glacier change were statistically significant along the East Antarctic Ice Sheet’s warmer Pacific Coast, but no significant changes were found along the much cooler Ross Sea Coast, which might be expected if climate is driving the changes, the Durham researchers said.Dr Stokes said that the cause of the recent trends in air temperature and sea ice were difficult to unravel but were likely to reflect a combination of both natural variability and human impacts.However, he added that the changes observed in glaciers in East Antarctica needed further investigation against the backdrop of likely increases in both atmospheric and ocean temperatures caused by climate change.Dr Stokes said: “If the climate is going to warm in the future, our study shows that large parts of the margins of the East Antarctic Ice Sheet are vulnerable to the kinds of changes that are worrying us in Greenland and West Antarctica — acceleration, thinning and retreat.”When temperatures warm in the air or ocean, glaciers respond by retreating and this can have knock-on effects further inland, where more and more ice is drawn-down towards the coast.”We need to monitor their behaviour more closely and maybe reassess our rather conservative predictions of future ice sheet dynamics in East Antarctica.”Read more
Aug. 26, 2013 — A study into marine life around an underwater volcanic vent in the Mediterranean, might hold the key to understanding how some species will be able to survive in increasingly acidic sea water should anthropogenic climate change continue.Researchers have discovered that some species of polychaete worms are able to modify their metabolic rates to better cope with and thrive in waters high in carbon dioxide (CO2), which is otherwise poisonous to other, often closely-related species.The study sheds new light on the robustness of some marine species and the relative resilience of marine biodiversity should atmospheric CO2 continue to cause ocean acidification.A team of scientists led by Plymouth University, and including colleagues from the Naples Zoological Station in Ischia; the Marine Ecology Laboratory ENEA in La Spezia, Italy; the University of Texas Galveston; and the University of Hull, conducted a three-year research project into the potential mechanisms that species of worm polychaetes use to live around the underwater CO2 vent of Ischia in Southern Italy.The researchers collected specimens found in waters characterised by either elevated or low levels of CO2, and placed them in specially-constructed ‘transplantation chambers’, which were then lowered into areas both within and away from the volcanic vent.They monitored the responses of the worms and found that one of the species that had been living inside the CO2 vent was physiologically and genetically adapted to the acidic conditions, whilst another was able to survive inside the vent by adjusting its metabolism.Project leader Dr Piero Calosi, of Plymouth University’s Marine Institute, said: “Previous studies have shown that single-cell algae can genetically adapt to elevated levels of carbon dioxide, but this research has demonstrated that a marine animal can physiologically and genetically adapt to chronic and elevated levels of carbon dioxide.”Furthermore, we show that both plasticity and adaptation are key to preventing some species’ from suffering extinction in the face of on-going ocean acidification, and that these two strategies may be largely responsible to defining the fate of marine biodiversity.”The results revealed that species normally found inside the CO2 vent were better able to regulate their metabolic rate when exposed to high CO2 conditions, whilst species only found outside the CO2 vent were clearly impaired by acidic waters. In fact, their metabolism either greatly decreased, indicating reduced energy production, or greatly increased, indicating a surge in the basic cost of living, in both cases making life inside the vent unsustainable.Dr Maria-Cristina Gambi, of the Naples Zoological Station in Ischia, explained: “Despite some species showing the ability to metabolically adapt and adjust to the extreme conditions that are found inside the CO2 vents, others appear unable to physiologically cope with such conditions.”In this sense, our findings could help to explain mass extinctions of the past, and potential extinctions in the future, as well as shed light on the resilience of some species to on-going ocean acidification.”The team also found that those species adapted to live inside the CO2 vent showed slightly higher metabolic rates and were much smaller in size — up to 80% smaller — indicating that adaptation came at a cost of energy for growth.Dr Calosi concluded that: ”Ultimately, species’ physiological responses to high CO2, as those reported by our study, may have repercussions on their abundance and distribution, and thus on the structure and dynamics of marine communities. This in turn will impact those ecosystem functions that humans rely upon to obtain goods and services from the ocean.”The research was funded by a Natural Environment Research Council UK Ocean Acidification Research Programme grant, and an Assemble Marine EU FP7 scheme.Read more
Aug. 15, 2013 — Climate change is set to trigger more frequent and severe heat waves in the next 30 years regardless of the amount of carbon dioxide (CO2) we emit into the atmosphere, a new study has shown.Extreme heat waves such as those that hit the US in 2012 and Australia in 2009 — dubbed three-sigma events by the researchers — are projected to cover double the amount of global land by 2020 and quadruple by 2040.Meanwhile, more-severe summer heat waves — classified as five-sigma events — will go from being essentially absent in the present day to covering around three per cent of the global land surface by 2040.The new study, which has been published on 15 August, in IOP Publishing’s journal Environmental Research Letters, finds that in the first half of the 21st century, these projections will occur regardless of the amount of CO2 emitted into the atmosphere.After then, the rise in frequency of extreme heat waves becomes dependent on the emission scenario adopted. Under a low emission scenario, the number of extremes will stabilise by 2040, whereas under a high emission scenario, the land area affected by extremes will increase by one per cent a year after 2040.Lead author of the study, Dim Coumou, from the Potsdam Institute for Climate Impact Research, said: “We find that up until 2040, the frequency of monthly heat extremes will increase several fold, independent of the emission scenario we choose to take. Mitigation can, however, strongly reduce the number of extremes in the second half of the 21st century.”Under a high emission scenario, the projections show that by 2100, 3-sigma heat waves will cover 85 per cent of the global land area and five-sigma heat waves will cover around 60 per cent of global land.”A good example of a recent three-sigma event is the 2010 heat wave in Russia, which expanded over a large area stretching from the Baltic to the Caspian Sea. In the Moscow region the average temperature for the whole of July was around 7°C warmer than normal — it was around 25°C. In some parts, temperatures above 40°C were measured,” continued Coumou.In their study, Dim Coumou, from the Potsdam Institute for Climate Impact Research, and Alexander Robinson, from Universidad Complutense de Madrid, used state-of-the-art climate models to project changes in the trend of heat extremes under two future warming scenarios — RCP2.6 and RCP8.5 — throughout the 21st century. The historic period was also analysed, and the results showed that the models can accurately reproduce the observed rise in monthly heat extremes over the past 50 years.Co-author of the study, Alexander Robinson, said: “Our three- and five-sigma thresholds are defined by the variability a region has experienced in the past, so the absolute temperatures associated with these types of event will differ in different parts of the world. Nonetheless these events represent a significant departure from the normal range of temperatures experienced in a given region.”According to the research, tropical regions will see the strongest increase in heat extremes, exceeding the threshold that is defined by the historic variability in the specific region. The results show that these changes can already be seen when analysing observations between 2000 and 2012.”Heat extremes can be very damaging to society and ecosystems, often causing heat-related deaths, forest fires or losses to agricultural production. So an increase in frequency is likely to pose serious challenges to society and some regions will have to adapt to more frequent and more severe heat waves already in the near-term,” continued Coumou.Read more
Aug. 1, 2013 — Climate change is affecting the spread of infectious diseases worldwide, according to an international team of leading disease ecologists, with serious impacts to human health and biodiversity conservation. Writing in the journal Science, they propose that modeling the way disease systems respond to climate variables could help public health officials and environmental managers predict and mitigate the spread of lethal diseases.The issue of climate change and disease has provoked intense debate over the past decade, particularly in the case of diseases that affect humans, according to the University of Georgia’s Sonia Altizer, who is the study’s lead author.”For a lot of human diseases, responses to climate change depend on the wealth of nations, healthcare infrastructure and the ability to take mitigating measures against disease,” said Altizer, an associate professor in the UGA Odum School of Ecology. “The climate signal, in many cases, is hard to tease apart from other factors like vector control and vaccine and drug availability.”Climate warming already is causing changes in diseases affecting wildlife and agricultural ecosystems, she said. “In many cases, we’re seeing an increase in disease and parasitism. But the impact of climate change on these disease relationships depends on the physiology of the organisms involved, the location on the globe and the structure of ecological communities.”At the organism level, climate change can alter the physiology of both hosts and parasites. Some of the clearest examples are found in the Arctic, where temperatures are rising rapidly, resulting in faster developing parasites. A lungworm that affects muskoxen, for instance, can now be transmitted over a longer period each summer, making it a serious problem for the populations it infects.”The Arctic is like a ‘canary in the global coal mine,'” said co-author Susan Kutz of the University of Calgary and Canadian Cooperative Wildlife Health Centre.”Climate warming in the Arctic is occurring more rapidly than elsewhere, threatening the health and sustainability of Arctic plants and animals, which are adapted to a harsh and highly seasonal environment and are vulnerable to invasions by ‘southern’ species — both animals and parasites.”A changing climate also is affecting entire plant and animal communities. This is particularly evident in tropical marine environments such as the world’s coral reef ecosystems. In places like the Caribbean, warmer water temperatures have stressed corals and facilitated infections by pathogenic fungi and bacteria. …Read more
Aug. 1, 2013 — Should climate change trigger the upsurge in heat and rainfall that scientists predict, people may face a threat just as perilous and volatile as extreme weather — each other.Researchers from Princeton University and the University of California-Berkeley report in the journal Science that even slight spikes in temperature and precipitation have greatly increased the risk of personal violence and social upheaval throughout human history. Projected onto an Earth that is expected to warm by 2 degrees Celsius by 2050, the authors suggest that more human conflict is a likely outcome of climate change.The researchers analyzed 60 studies from a number of disciplines — including archaeology, criminology, economics and psychology — that have explored the connection between weather and violence in various parts of the world from about 10,000 BCE to the present day. During an 18-month period, the Princeton-Berkeley researchers reviewed those studies’ data — and often re-crunched raw numbers — to calculate the risk that violence would rise under hotter and wetter conditions.They found that while climate is not the sole or primary cause of violence, it undeniably exacerbates existing social and interpersonal tension in all societies, regardless of wealth or stability. They found that 1 standard-deviation shift — the amount of change from the local norm — in heat or rainfall boosts the risk of a riot, civil war or ethnic conflict by an average of 14 percent. There is a 4 percent chance of a similarly sized upward creep in heat or rain sparking person-on-person violence such as rape, murder and assault. The researchers report that climate-change models predict an average of 2 to 4 standard-deviation shifts in global climate conditions by 2050.Establishing a correlation between violence and climate change now allows policymakers and researchers to examine what causes it and how to intervene, said lead author Solomon Hsiang, who conducted the work as a postdoctoral research associate in the Program in Science, Technology and Environmental Policy in Princeton’s Woodrow Wilson School of Public and International Affairs.”We think that by collecting all the research together now, we’re pretty clearly establishing that there is a causal relationship between the climate and human conflict,” Hsiang said. “People have been skeptical up to now of an individual study here or there. But considering the body of work together, we can now show that these patterns are extremely general. It’s more of the rule than the exception.”Whether there is a relationship between climate and conflict is not the question anymore. …Read more
July 30, 2013 — Long isolated by economic and political sanctions, Myanmar returns to the international community amid high expectations and challenges associated with protecting the country’s great natural wealth from the impacts of economic growth and climate change.In a new study, scientists from the Wildlife Conservation Society have examined the implications of economic development and climatic changes on conserving Myanmar’s biodiversity and provide recommendations for conservation planning within a context of a changing climate by strengthening the protected area system and engaging in ecosystem-based adaptation strategies.The paper appears in the latest edition of AMBIO: A Journal of the Human Environment. The authors include: Madhu Rao, Saw Htun, Steven G. Platt, Rob J. Tizard, Colin M. Poole, Than Myint, and James E.M. Watson of the Wildlife Conservation Society.”For many years, Myanmar’s isolation has served to protect the biodiversity which has disappeared from many other regions in Southeast Asia,” said Wildlife Conservation Society’s Dr. Madhu Rao, lead author of the study. “Things are now changing rapidly for Myanmar, which will soon experience increasing economic growth and the myriad cascading effects of climate change on its forests and coastlines. The opportunity to protect the country’s natural heritage with a strategic and multi-faceted approach is now.”Unlike many other countries in the region, Myanmar still contains high levels of biodiversity along with vast swaths of natural forests. The country contains a wide assemblage of habitats including lowland tropical forests and mangrove ecosystems that are increasingly degraded and depleted elsewhere in the region. …Read more
July 26, 2013 — Recently, climate change, including global warming, has been a “hot” news item as many regions of the world have experienced increasingly intense weather patterns, such as powerful hurricanes and extended floods or droughts. Often the emphasis is on how such extreme weather impacts humans, from daily heat index warnings to regulating CO2 emissions. While the media continues to present climate change as a controversial issue, many scientists are working hard to gather data, collaborate across disciplines, and use experimental and modeling techniques to track how organisms and ecosystems are responding to the current changes in our Earth’s global environment.A group of organisms that play a wide variety of crucial roles in our global ecosystems is plants. What role do plants play in helping to regulate climate change and how will they fare in future times? A new series of articles in a Special Issue on Global Biological Change in the American Journal of Botany expands our view on how global changes affect and are affected by plants and offers new ideas to stimulate and advance new collaborative research.Global change includes topics such as increasing carbon dioxide and its effect on climate, habitat fragmentation and changes in how protected and agricultural lands are used or managed, increases in alien species invasions, and increased use of resources by humans. There is increasing concern that these changes will have rapid and irreversible impacts on our climate, our resources, our ecosystems, and ultimately on life, as we know it. These concerns stimulated Stephen Weller (University of California, Irvine), Katharine Suding (University of California, Berkeley), and Ann Sakai (University of California, Irvine) to gather together a diverse series of work from botanists spanning disciplines from taxonomy and morphology to ecology and evolution, from traditional to multidisciplinary approaches, and from observations and experiments to modeling and reviews, to help synthesize our knowledge and stimulate new approaches to tackling these global biological change issues.”We have been concerned about the rapid and irreversible changes associated with a rapidly increasing human population that is already over seven billion people,” commented Weller. “Many people are familiar with the impact of rising temperatures and greater intensity of storms on humans, but have less understanding of the effects of these and other global changes on the foundation of our biological ecosystems — plants.”Focusing on a group of organisms such as plants may help provide us with insights into how such crucial organisms have responded to climate changes in the past and how they might respond to future changes. Moreover, since impacts occur from the cellular and molecular basis to the ecosystem and evolutionary scale, this Special Issue provides an excellent opportunity to synthesize the current knowledge of global change effects on a wide spectrum of aspects of plant biology, ecology, and evolution.”Plant biologists work at different levels of organization with diverse approaches and techniques to address questions about global change,” notes Suding. “What is the effect of global change on plants, and how are plants affected by global change? …Read more
July 15, 2013 — Under elevated carbon dioxide levels, wetland plants can absorb up to 32 percent more carbon than they do at current levels, according to a 19-year study published in Global Change Biology from the Smithsonian Environmental Research Center in Edgewater, Md. With atmospheric CO2 passing the 400 parts-per-million milestone this year, the findings offer hope that wetlands could help soften the blow of climate change.Plant physiologist Bert Drake created the Smithsonian’s Global Change Ecological Research Wetland in 1987 at Edgewater. Back then, most scientists thought plants would gradually stop responding to rising CO2. Whether or not terrestrial ecosystems could assimilate additional carbon—and act as powerful carbon sinks—was not known. This study tracked not only how much CO2 wetlands absorb, but also the impact of rising temperature and sea level, changing rainfall and plant type.To simulate a high-CO2 world, Drake’s team surrounded marsh plots with open-top Mylar chambers. For this study they left half of the chambers exposed to today’s atmosphere. In the other half they added CO2 and raised the level to 700 ppm, roughly doubling the CO2 concentration as it was in 1987. Other plots of land were left without chambers. They compared the levels of CO2 going in and CO2 going out to determine the carbon exchange between the wetland and the atmosphere.Two types of plants populate most of the world, and the experiment tested both. C3 plants—which include more than 95 percent of the plant species on earth, including trees—form molecules of three carbon atoms during photosynthesis, and they tend to photosynthesize more as atmospheric CO2 rises. …Read more
July 11, 2013 — Many birds feed on mosquitoes that spread the West Nile virus, a disease that killed 286 people in the United States in 2012 according to the Centers for Disease Control. Birdsalso eat insects that can be agricultural pests. However, rising temperatures threaten wild birds, including the Missouri-native Acadian flycatcher, by making snakes more active, according to University of Missouri biologist John Faaborg. He noted that farmers, public health officials and wildlife managers should be aware of complex indirect effects of climate change in addition to the more obvious influences of higher temperatures and irregular weather patterns.Share This:”A warmer climate may be causing snakes to become more active and seek more baby birds for food,” said Faaborg, professor of biological sciences in MU’s College of Arts and Science. “Although our study used 20 years of data from Missouri, similar threats to bird populations may occur around the world. Increased snake predation on birds is an example of an indirect consequence that forecasts of the effects of climate change often do not take into account.”In the heart of Missouri’s Ozark forest, cooler temperatures usually make snakes less active than in the edge of the forest or in smaller pockets of woodland. However, during abnormally hot years, even the interior of the forest increases in temperature. Since snakes are cold-blooded, warmer temperatures make the reptiles more active and increase their need for food. Previous studies using video cameras found that snakes are major predators of young birds.Over the past twenty years, fewer young Acadian flycatchers (Empidonax virescens) survived during hotter years, according to research by Faaborg and his colleagues published in the journal Global Change Biology. Survival of young indigo buntings (Passerina cyanea) also decreased during warmer years. …Read more
June 26, 2013 — A new report on sea level rise recommends that the State of Maryland should plan for a rise in sea level of as much as 2 feet by 2050. Led by the University of Maryland Center for Environmental Science, the report was prepared by a panel of scientific experts in response to Governor Martin O’Malley’s Executive Order on Climate Change and “Coast Smart” Construction. The projections are based on an assessment of the latest climate change science and federal guidelines.”The State of Maryland is committed to taking the necessary actions to adapt to the rising sea and guard against the impacts of extreme storms,” said Governor Martin O’Malley. “In doing so, we must stay abreast of the latest climate science to ensure that we have a sound understanding of our vulnerability and are making informed decisions about how best to protect our land, infrastructure, and most importantly, the citizens of Maryland.”The independent, scientific report recommends that is it is prudent to plan for sea level to be 2.1 feet higher in 2050 along Maryland’s shorelines than it was in 2000 in order to accommodate the high end of the range of the panel’s projections. Maryland has 3,100 miles of tidal shoreline and low-lying rural and urban lands that will be impacted. The experts’ best estimate for the amount of sea-level rise in 2050 is 1.4 feet. It is unlikely to be less than 0.9 feet or greater than 2.1 feet. Their best estimate for sea level rise by 2100 is 3.7 feet. They concluded that it is unlikely to be less than 2.1 feet or more than 5.7 feet based on current scientific understanding.”This reassessment narrows the probable range of sea level rise based on the latest science,” said Donald Boesch, president of the University of Maryland Center for Environmental Science and chair of the group of experts that assembled the report. “It provides the State with sea level rise projections based on best scientific understanding to ensure that infrastructure is sited and designed in a manner that will avoid or minimize future loss or damage.”These estimates were made based on the various contributors to sea level rise: thermal expansion of ocean volume as a result of warming, the melting of glaciers and Greenland and Antarctic ice sheets, changing ocean dynamics such as the slowing of the Gulf Stream, and vertical land movement.”While there is little we can do now to reduce the amount of sea-level rise by the middle of the century, steps taken over the next 30 years to control greenhouse gas emissions and stabilize global temperatures will largely determine how great the sea level rise challenge will be for coastal residents at the end of this century and beyond,” said Dr. …Read more
June 12, 2013 — In the race against climate change and ocean acidification, some sea urchins may still have a few tricks up their spiny sleeves, suggesting that adaptation will likely play a large role for the sea creatures as the carbon content of the ocean increases.”What we want to know is, given that this is a process that happens over time, can marine animals adapt? Could evolution come to the rescue?” said postdoctoral researcher Morgan Kelly, from UC Santa Barbara’s Department of Ecology, Evolution and Marine Biology. She is a co-author of the paper “Natural variation, and the capacity to adapt to ocean acidification in the keystone sea urchin Strongylocentrotus purpuratus.” The paper was published in the latest edition of the journal Global Change Biology.Easily identified by their spherical symmetry and prickly barbs, sea urchins are found on the sea floor all over the world. They are considered a keystone species, meaning their population has an important impact on the rest of the undersea ecosystem. Too many of them and their habitat becomes barren and other algae-eating species disappear; too few and their predators — including sea mammals, seabirds, and fish — lose an important food source.Due to rising carbon dioxide in Earth’s atmosphere, the oceans of the future are projected to absorb more carbon dioxide, leading to acidification of the water. The change in the ocean chemistry is expected to negatively affect the way urchins and other calcifying creatures create and maintain their shells and exoskeletons.”It gives them osteoporosis,” said Kelly. Increased water acidity would cause the levels of calcium carbonate — which the sea urchins require — to decrease. This, in turn, would result in smaller animals, thinner shells and perhaps shorter spines for the urchins.To observe the potential effects of future increased levels of carbon dioxide in ocean water, the researchers bred generations of purple sea urchins in conditions mimicking projected environment of the ocean in near the end of the century.”We exposed them to 1,100 parts per million of carbon dioxide,” Kelly said. Current CO2 levels top off at about 400 parts per million and the levels are expected to increase globally to 700 parts per million by the end of the century. In the California region, however, CO2 levels in the ocean naturally fluctuate because of cold water upwelling, a phenomenon that also brings more acidic waters.The animals were taken from two locations off the California coast — a northern site, which experiences greater upwelling, and a southern site that experiences shorter, less frequent bouts of upwelling. …Read more
June 2, 2013 — Tree cover in the tropics will likely change in surprising ways as climate change increases the frequency of extreme rainfall events, according to a study by scientists from Wageningen University published today in Nature Climate Change.The study shows that increasing year-to year variability in rainfall is associated to lower tree cover in the moist tropical forests worldwide but it can open windows of opportunity for tree expansion in some tropical drylands.”Understanding how ecosystems respond to climate variability is a priority in a fast changing globe” says Marten Scheffer, who leads the research program on tipping points. “Climate events can open windows of opportunity for abrupt changes in ecosystems. We are starting to glimpse on the complexity of these patterns” says Scheffer.”The overall effects of climate variability are puzzling. On one hand, severe drought can produce massive tree mortality, but there is also evidence of episodic tree recruitment during extreme rainy years” says Milena Holmgren, leading author of the study and a specialist on plant ecology.Satellite dataThe authors used satellite data to look at large scale patterns of tree cover across the tropics of Africa, Australia and South America. They show that increasing rainfall variability is associated to lower tree cover in the moist tropical forests of all continents. In the dry tropics, however, the effects of higher year-to year variability in rainfall depend on the specific continent. Higher overall inter-annual variation in rainfall has positive (South America), negative (Australia) or neutral effects (Africa) on tree cover in dry-lands. “The effects of climate variability in tropical drylands seem to depend on the balance between wet and dry extreme events, as well as on the opportunities trees have to grow during rainy events,” says Milena Holmgren. “We knew from small scale experiments in South America and observations in Australia that rainy years can be essential for tree recruitment in drylands. During extreme rainy years there is massive tree germination and if these young seedlings grow fast enough to escape from herbivores, then woodlands can expand. …Read more
Apr. 9, 2013 — Environmental change can drive hard-wired evolutionary changes in animal species in a matter of generations. A University of Leeds-led study, published in the journal Ecology Letters, overturns the common assumption that evolution only occurs gradually over hundreds or thousands of years.
Instead, researchers found significant genetically transmitted changes in laboratory populations of soil mites in just 15 generations, leading to a doubling of the age at which the mites reached adulthood and large changes in population size. The results have important implications in areas such as disease and pest control, conservation and fisheries management because they demonstrate that evolution can be a game-changer even in the short-term.
Professor Tim Benton, of the University of Leeds’ Faculty of Biological Sciences, said: “This demonstrates that short-term ecological change and evolution are completely intertwined and cannot reasonably be considered separate. We found that populations evolve rapidly in response to environmental change and population management. This can have major consequences such as reducing harvesting yields or saving a population heading for extinction.”
Although previous research has implied a link between short-term changes in animal species’ physical characteristics and evolution, the Leeds-led study is the first to prove a causal relationship between rapid genetic evolution and animal population dynamics in a controlled experimental setting.
The researchers worked with soil mites that were collected from the wild and then raised in 18 glass tubes. Forty percent of adult mites were removed every week from six of the glass tubes. A similar proportion of juveniles were removed each week in a further six tubes, while no “harvesting” was conducted in the remaining third of the tubes.
Lead author Dr Tom Cameron, a postdoctoral Fellow in the Faculty of Biological Sciences at Leeds at the time of the research and now based in Umeå University, Sweden, said: “We saw significant evolutionary changes relatively quickly. The age of maturity of the mites in the tubes doubled over about 15 generations, because they were competing in a different way than they would in the wild. Removing the adults caused them to remain as juveniles even longer because the genetics were responding to the high chance that they were going to die as soon as they matured. When they did eventually mature, they were so enormous they could lay all of their eggs very quickly.”
The initial change in the mites’ environment — from the wild into the laboratory — had a disastrous effect on the population, putting the mites on an extinction trajectory. However, in every population, including those subjected to the removal of adults or juveniles, the trajectory switched after only five generations of evolution and the population sizes began to increase.
The researchers found that the laboratory environment was selecting for those mites that grew more slowly. Under the competitive conditions in the tubes, the slow growing mites were more fertile when they matured, meaning they could have more babies.
Dr Cameron said: “The genetic evolution that resulted in an investment in egg production at the expense of individual growth rates led to population growth, rescuing the populations from extinction. This is evolutionary rescue in action and suggests that rapid evolution can help populations respond to rapid environmental change.”
Short-term ecological responses to the environment — for instance, a reduction in the size of adults because of a lack of food — and hard-wired evolutionary changes were separated by placing mites from different treatments into a similar environment for several generations and seeing whether differences persisted.
Professor Benton said: “The traditional idea would be that if you put animals in a new environment they stay basically the same but the way they grow changes because of variables like the amount of food. However, our study proves that the evolutionary effect — the change in the underlying biology in response to the environment — can happen at the same time as the ecological response. Ecology and evolution are intertwined,” he said.
Unpicking evolutionary change from ecological responses is particularly important in areas such as the management of fisheries, where human decisions can result in major changes to an entire population’s environment and life histories. The size at which cod in the North Sea mature is about half that of 50 years ago and this change has been linked to a collapse in the cod population because adult fish today are less fertile than their ancestors.
“The big debate has been over whether this is an evolutionary response to the way they are fished or whether this is, for instance, just the amount of food in the sea having a short-term ecological effect. Our study underlined that evolution can happen on a short timescale and even small 1 to 2 per cent evolutionary changes in the underlying biology caused by your harvesting strategy can have major consequences on population growth and yields. You can’t just try to bring the environment back to what it was before and expect everything to return to normal,” Professor Benton said.
The research was funded by the Natural Environment Research Council (NERC) and involved researchers from the University of Leeds and Professor Stuart Piertney of the University of Aberdeen’s School of Biological Sciences.Read more
May 16, 2013 — After reviewing recent research based on the study of habitat-specialist coral reef fishes, Boston University post-doctoral researcher Marian Y. L. Wong and Peter M. Buston, assistant professor of biology, have found that these species have proven invaluable for experimental testing of key concepts in social evolution, noting that studies of these fishes already have yielded insights about the ultimate reasons for female reproductive suppression, group living, and bidirectional sex change. Based on this impressive track record, the researchers maintain that these fishes should be the focus of future tests of key concepts in evolutionary ecology.
A major focus in evolutionary ecology lies in explaining the evolution and maintenance of social systems. Although most theoretical formulations of social system evolution were initially inspired by studies of birds, mammals, and insects, incorporating a wider taxonomic perspective is important for testing deeply entrenched theory. In their new study, the researchers suggest that habitat-specialist coral reef fishes provide that wider perspective.
“While such coral reef fishes are ecologically similar, they display remarkable variation in mating systems, social organization, and sex allocation strategies,” says Wong. “Our review of recent research clearly shows the amenability of these fishes for experimental testing of key concepts in social evolution.”
The new study highlights recent contributions made by one specific group of coral reef fishes — habitat-specialist reef fishes — to testing the robustness of mating system, cooperative breeding, and sex allocation theories. Habitat-specialist reef fishes are small bodied and well adapted to living within discrete patches of coral, anemones, and sponges. They include such species as the Pomacentridae (damselfish), Gobiidae (goby), Caracanthidae (coral croucher), and Cirrhitidae (hawkfish) families.
Being habitat specialists, these fishes are highly site attached and have limited mobility. They rely on their particular habitat for food, shelter, and breeding sites, and they experience high risks of mortality from predation if they venture outside their immediate habitat. Mating systems are highly variable both among and within these species, including monogamy (one male mates with one female), harem polygyny (one male mates with several females), and polygynandry (multiple males and females mate with each other). These fishes also exhibit great variability in social organization, including pair and group formation, with group members’ being reproductive or non-reproductive depending on the mating system. “This behavioral variability, despite the relative ecological similarity of these species, presents a unique opportunity to test the various hypotheses for the evolution of different social systems,” says Buston.
According to the authors, habitat-specialist reef fishes are a tried and tested group of model organisms for advancing the understanding of the evolution and ecology of social systems in animals; the study of these species already has revealed many things about the evolutionary ecology of mating, social, and sexual systems. Despite their ecological quirkiness, they have been instrumental for testing the generality and robustness of key concepts that are widely applicable to other taxonomic groups. In fact, in some cases, they have been the only species in which experimental tests of key hypotheses have been performed, largely because of the ease with which their habitat and social organization can be manipulated in the lab and in the field. For these reasons, the authors argue that these species should be the focus of future tests of key concepts in evolutionary ecology.Read more