Changes in agriculture increase high river flow rates

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Just as a leaky roof can make a house cooler and wetter when it’s raining as well as hotter and dryer when it’s sunny, changes in land use can affect river flow in both rainy and dry times, say two University of Iowa researchers.While it may be obvious that changes in river water discharge across the U.S. Midwest can be related to changes in rainfall and agricultural land use, it is important to learn how these two factors interact in order to get a better understanding of what the future may look like, says Gabriele Villarini, UI assistant professor of civil and environmental engineering, assistant research engineer at IIHR — Hydroscience & Engineering and lead author of a published research paper on the subject.”We wanted to know what the relative impacts of precipitation and agricultural practices played in shaping the discharge record that we see today,” he says. “Is it an either/or answer or a much more nuanced one?”By understanding our past we are better positioned in making meaningful statements about our future,” he says.The potential benefits of understanding river flow are especially great in the central United States, particularly Iowa, where spring and summer floods have hit the area in 1993, 2008, 2013 and 2014, interrupted by the drought of 2012. Large economic damage and even loss of life have resulted, says co-author Aaron Strong, UI assistant professor in the Department of Urban and Regional Planning and with the Environmental Policy Program at the UI Public Policy Center.”What is interesting to note,” says Strong, “is that the impacts, in terms of flooding, have been exacerbated. At the same time, the impacts of drought, for in-stream flow, have been mitigated with the changes in land use composition that we have seen over the last century.”In order to study the effect of changes in agricultural practices on Midwest river discharge, the researchers focused on Iowa’s Raccoon River at Van Meter, Iowa. The 9,000-square-kilometer watershed has the advantage of having had its water discharge levels measured and recorded daily for most of the 20th century right on up to the present day. (The study focused on the period 1927-2012). During that period, the number of acres used for corn and soybean production greatly increased, roughly doubling over the course of the 20th century.Not surprisingly, they found that variability in rainfall is responsible for most of the changes in water discharge volumes.However, the water discharge rates also varied with changes in agricultural practices, as defined by soybean and corn harvested acreage in the Raccoon River watershed. In times of flood and in times of drought, water flow rates were exacerbated by more or less agriculture, respectively. The authors suggest that although flood conditions may be exacerbated by increases in agricultural production, this concern “must all be balanced by the private concerns of increased revenue from agricultural production through increased cultivation.””Our results suggest that changes in agricultural practices over this watershed — with increasing acreage planted in corn and soybeans over time — translated into a seven-fold increase in rainfall contribution to the average annual maximum discharge when we compare the present to the 1930s,” Villarini says.The UI research paper, “Roles of climate and agricultural practices in discharge changes in an agricultural watershed in Iowa,” can be found in the April 15 online edition of Agriculture, Ecosystems & Environment.Story Source:The above story is based on materials provided by University of Iowa. …


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Crop species may be more vulnerable to climate change than we thought

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A new study by a Wits University scientist has overturned a long-standing hypothesis about plant speciation (the formation of new and distinct species in the course of evolution), suggesting that agricultural crops could be more vulnerable to climate change than was previously thought.Unlike humans and most other animals, plants can tolerate multiple copies of their genes — in fact some plants, called polyploids, can have more than 50 duplicates of their genomes in every cell. Scientists used to think that these extra genomes helped polyploids survive in new and extreme environments, like the tropics or the Arctic, promoting the establishment of new species.However, when Dr Kelsey Glennon of the Wits School of Animal, Plant and Environmental Sciences and a team of international collaborators tested this long-standing hypothesis, they found that, more often than not, polyploids shared the same habitats as their close relatives with normal genome sizes.”This means that environmental factors do not play a large role in the establishment of new plant species and that maybe other factors, like the ability to spread your seeds to new locations with similar habitats, are more important,” said Glennon.”This study has implications for agriculture and climate change because all of our important crops are polyploids and they might not be much better at adapting to changing climate than their wild relatives if they live in similar climates.”Glennon’s study also provides an alternative explanation for why plants are so diverse in places like the Cape where the climate has been stable for hundreds of thousands of years. Although her study examined plant species from North America and Europe only, she is looking forward to testing her hypotheses using South African plants.Glennon’s paper has been published in Ecology Letters.Story Source:The above story is based on materials provided by Wits University. Note: Materials may be edited for content and length.


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Seal evolution: Sexual dimorphism in pinnipeds arose around 27 million years ago as climate changed

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In the world of science, one of the most exciting things a researcher can do is pin down an answer to a widely asked question. This experience came early for Carleton University graduate Thomas Cullen, who made a discovery about pinnipeds — the suborder that makes up seals, sea lions and walruses — while doing research for his Master’s degree under the supervision of Canadian Museum of Nature palaeontologist Dr. Natalia Rybczynski.His discovery, published today in the journal Evolution, relates to sexual dimorphism (a large variance in size between males and females), in a variety of pinniped species. Males in many species of pinnipeds are often much larger than their female counterparts, in some cases more than twice as large, and this has implications for how they mate and behave.Dimorphic pinnipeds such as the Steller’s Sea Lion and Northern Fur Seal typically mate in a harem, with one male pinniped presiding over a larger community of female mates. This behavior is not typically seen in non-dimorphic pinnipeds such as the Ringed Seal, and so sexual dimorphism is intimately linked with mating style.Researchers have long puzzled over both why sexual dimorphism exists in many pinniped species and when this trait evolved. When Cullen examined fossils of an extinct pinniped with Rybczynski, he discovered an incontrovertible answer to the question of when. He was able to examine it there before analyzing the data at Carleton in a lab headed by his other thesis supervisor, Prof. Claudia Schrder-Adams.Skull of Enaliarctos emlongi, an early pinniped ancestor. Cullen examined and analyzed the characteristics of this fossil for his study on the evolution of sexual dimorphism in pinnipeds.”We were examining a fossil of a pinniped that was previously thought to be a juvenile, but we looked at it again and found that, based on its skull structure, it was likely an adult,” says Cullen. This discovery, coupled with analyses comparing this fossil to others of the same species as well as modern dimorphic species, proved that the fossil belonged to a sexually dimorphic species.The fossil in question, the skull of an early pinniped ancestor called Enaliarctos emlongi, was discovered in the late 1980s off the coast of Oregon. …


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Extreme weather images in the media cause fear and disengagement with climate change

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The paper ‘ Images of Extreme Weather: Symbolising Human Responses to Climate Change’, by Brigitte Nerlich & Rusi Jaspal, published in Science as Culture, reveals that extreme weather images represent human suffering and loss. They are iconic of climate change and are symbols of its natural impacts.Reporting on extreme weather has increased over the last few years. In the past social scientists, and media and communication analysts have studied how climate change is depicted in the text of media and social media. While researchers have become increasingly interested in climate change images, they have not yet studied them with respect to symbolising certain emotions.The International Panel on Climate Change (IPCC) published a draft report on extreme weather and climate change adaptation. The report was covered in the news and illustrated with images. Some of these depicted ‘extreme weather’, in particular with relation to floods, droughts and heat waves, hurricanes and ice/sea-level rise.Researchers studied images published in the news to illustrate their coverage of the IPCC report. They used visual thematic analysis, examining the way they might symbolise certain emotional responses, such as compassion, fear, guilt, vulnerability, helpless, courage or resilience.Results showed that images of flooding displays people in the developing world ‘getting on with it’. It portrays individuals accustomed to flooding and that they can overcome the extreme weather. The images showed cheerful behaviour of those who are affected by flooding; lack of victimhood; engagement in their day-to-day activities and communal aspects of coping with flooding.New research has shown that images of extreme weather in the media create negative emotional meanings and might lead to disengagement with the issue of climate change. The images symbolised fear, helplessness and vulnerability and, in some cases, guilt and compassion. …


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Arctic biodiversity under serious threat from climate change

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Unique and irreplaceable Arctic wildlife and landscapes are crucially at risk due to global warming caused by human activities according to the Arctic Biodiversity Assessment (ABA), a new report prepared by 253 scientists from 15 countries under the auspices of the Conservation of Arctic Flora and Fauna (CAFF), the biodiversity working group of the Arctic Council.”An entire bio-climatic zone, the high Arctic, may disappear. Polar bears and the other highly adapted organisms cannot move further north, so they may go extinct. We risk losing several species forever,” says Hans Meltofte of Aarhus University, chief scientist of the report.From the iconic polar bear and elusive narwhal to the tiny Arctic flowers and lichens that paint the tundra in the summer months, the Arctic is home to a diversity of highly adapted animal, plant, fungal and microbial species. All told, there are more than 21,000 species.Maintaining biodiversity in the Arctic is important for many reasons. For Arctic peoples, biodiversity is a vital part of their material and spiritual existence. Arctic fisheries and tourism have global importance and represent immense economic value. Millions of Arctic birds and mammals that migrate and connect the Arctic to virtually all parts of the globe are also at risk from climate change in the Arctic as well as from development and hunting in temperate and tropical areas. Marine and terrestrial ecosystems such as vast areas of lowland tundra, wetlands, mountains, extensive shallow ocean shelves, millennia-old ice shelves and huge seabird cliffs are characteristic to the Arctic. These are now at stake, according to the report.”Climate change is by far the worst threat to Arctic biodiversity. Temperatures are expected to increase more in the Arctic compared to the global average, resulting in severe disruptions to Arctic biodiversity some of which are already visible,” warns Meltofte.A planetary increase of 2 C, the worldwide agreed upon acceptable limit of warming, is projected to result in vastly more heating in the Arctic with anticipated temperature increases of 2.8-7.8 C this century. …


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Meeting the eye-witnesses of ocean change

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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. …


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New maps reveal locations of species at risk as climate changes

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


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Aquatic Insects – a tremendous potential for research on diversification

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Inland waters cover less than 1% of Earth’s surface yet harbor 10% of all known animal species, 60% of them being aquatic insects. Nearly 100,000 species from 12 orders spend one or more life stages in freshwater. Still today, little is known on how this remarkable diversity arose. Scientists of the Biodiversity and Climate Research Centre (BiK-F), the Naturalis Biodiversity Center in Leiden and the Leibniz-Institute of Freshwater Ecology and Inland Fisheries (IGB) in Berlin therefore investigated the potential of aquatic insects for research on diversification. The results have now been published in the journal Annual Review of Entomology.Freshwaters cover less than 1% of Earth’s surface, but harbour 10% of all animal species. Six out of ten of currently known species are insects. In a recently published review an international team of researchers from the Biodiversity and Climate Research Centre (BiK-F), the Biodiversity Center in Leiden, and the Leibniz-Institute of Freshwater Ecology and Inland Fisheries (IGB) in Berlin analyzed how studying the vast diversity of aquatic insects may contribute to a better understanding of diversification processes.”Analyzing the reasons behind the disproportionately high degree of aquatic insect diversity relative to the little area covered by freshwaters may help us to better understand species diversification,” specifies Dr. Steffen Pauls, leader of a junior research group at the BiK-F and one of the authors of the review.All aquatic insect groups are the result of the invasion of freshwaters by terrestrial groups: “Although belonging to only 12 orders, aquatic insects may represent more than 50 separate invasions,” explains co-author Dr. Klaas-Douwe Dijkstra from the Naturalis Biodiversity Center Leiden. The ecology and habitat preferences of many aquatic insect groups have been intensively studied, due to their roles as disease vectors or bioindicators for water quality. …


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