Three extreme weather events in the Amazon Basin in the last decade are giving scientists an opportunity to make observations that will allow them to predict the impacts of climate change and deforestation on some of the most important ecological processes and ecosystem services of the Amazon River wetlands.Scientists from Virginia Tech, the Woods Hole Research Center, and the University of California, Santa Barbara, funded by NASA, are collaborating with Brazilian scientists to explore the ecosystem consequences of the extreme droughts of 2005 and 2010 and the extreme flood of 2009.”The research fills an important gap in our understanding of the vulnerability of tropical river-forest systems to changes in climate and land cover,” said the project’s leader, Leandro Castello, assistant professor of fish and wildlife conservation in Virginia Tech’s College of Natural Resources and Environment.The huge study area encompasses 1.7 million square miles, the equivalent of half of the continental United States.In addition to historical records and ground observations, the researchers will use newly available Earth System Data Records from NASA — satellite images of the Amazon and its tributaries over the complete high- and low-water cycles.NASA is funding the study with a $1.53 million grant shared among the three institutions.”Amazon floodplains and river channels — maintained by seasonal floods — promote nutrient cycling and high biological production, and support diverse biological communities as well as human populations with one of the highest per capita rates of fish consumption,” said Castello.The researchers will look at how the natural seasonality of river levels influences aquatic and terrestrial grasses, fisheries, and forest productivity in the floodplains, and how extreme events such as floods and droughts may disturb this cycle.”We are confident that deforestation and climate change will, in the future, lead to more frequent and severe floods and droughts,” said Michael Coe, a senior scientist at the Woods Hole Research Center. “It is important that we understand how the Amazon River and ecosystem services such as fisheries are affected so that we can devise mitigation strategies.”Amazonian grasses, sometimes called macrophytes, convert atmospheric carbon to plant biomass, which is then processed by aquatic microorganisms upon decomposition.”Terrestrial grasses grow during the short window when water levels are low, sequestering some carbon, and then die when the floods arrive, releasing the carbon into the aquatic system,” said Thiago Silva, an assistant professor of geography at So Paulo State University in Rio Claro, Brazil. “They are followed by aquatic grasses that need to grow extremely fast to surpass the rising floods and then die off during the receding-water period.””Although most of the macrophyte carbon is released back to the atmosphere in the same form that it is assimilated, carbon dioxide, some of it is actually exported to the ocean as dissolved carbon or released to the atmosphere as methane, a gas that has a warming potential 20 times larger than carbon dioxide,” said John Melack, a professor at the University of California, Santa Barbara.Researchers will measure plant growth and gas exchange, and use photographs from the field and satellites.Two other Amazon resources — fisheries and forests — are important to the livelihood of the people of the region.”We will combine water level, fishing effort, and fish life-history traits to understand the impact of droughts and floods on fishery yields,” said Castello, whose specialty is Amazon fisheries. “Floods in the Amazon are almost a blessing because in some years they can almost double the amount of fish in the river that is available for fishermen and society.”The fishery data include approximately 90,000 annual interview records of fisheries activities on the number of fishers, time spent fishing, characteristics of fishing boats and gear used, and weight of the catch for 40 species. The hydrological data include daily water level measurements recorded in the Madeira, Purus, and Amazonas-Solimes rivers.The researchers will examine the potential impact of future climate scenarios on the extent and productivity of floodplain forests — those enriched by rising waters, called whitewater river forests, and nutrient-poor blackwater river forests.For example, extreme droughts may reduce productivity due to water stress and increases in the frequency and severity of forest fires. Prolonged periods of inundation, on the other hand, may decrease productivity or increase mortality due to water-logging stress.”We will evaluate these responses for the first time at a regional scale using remotely sensed indicators of vegetation condition and fire-induced tree mortality to measure the response of floodplain forests to inter-annual flood variability and extreme climate events,” said Marcia Macedo, a research associate at the Woods Hole Research Center.Researchers will measure tree litter dry weight, depth of flooding, tree height and diameter, and stand density. They will also use photographs and satellite images.Previous research has focused on Amazon upland forests and the potential impacts of deforestation, fire, and drought. The research team will compare new greenhouse gas simulations to previous simulations.”Our research informs large river ecology globally because natural flowing rivers like the Amazon are rare these days, and most research to date, being done in North America and Europe, has focused on degraded systems,” Castello said.Read more
Oct. 16, 2013 — In a study published recently in the journal Physiology & Behavior an international team of researchers examined whether cats living in multi-cat households are more stressed than cats housed singly. Many media outlets responded to the study with an incorrect interpretation of the results and published such as “Cats Hate to be Stroked.” The co-author Rupert Palme of the Institute of Medical Biochemistry at the University of Veterinary Medicine, Vienna, explains: “As a matter of fact, the majority of the cats enjoyed being stroked. Only those animals that did not actually like to be stroked, but nevertheless allowed it, were stressed.”Share This:The actual aim of the study was to find out whether cats are more stressed when they live in large groups together or, whether the strict hierarchy of larger groups reduces stress. Neither could be confirmed in the present study. The number of cats per household had no influence on the stress of the animals. Rather, stress in domestic cats depends more on the socialization of the animals, on the relationship with humans, on the space available to them or on the access to food.Every cat feels and reacts differentlyThe researchers studied 120 cats in 60 Brazilian households. These were divided into three different categories: group I: 23 single-cat households, group II: 20 multi-cat households with two cats; group III: 17 multi-cat households with three to four cats. The cat owners were asked to classify their pets as “bossy,” “timid” or “easy going” in order to assess the personality. Furthermore, the cat owners reported how much each cat liked to be stroked. …Read more
Oct. 9, 2013 — A mathematician has calculated how peer pressure influences society.Professor Ernesto Estrada, of the University of Strathclyde’s Department of Mathematics and Statistics, examined the effect of direct and indirect social influences — otherwise known as peer pressure — on how decisions are reached on important issues. Using mathematical models, he analysed data taken from 15 networks — including US school superintendents and Brazilian farmers — to outline peer pressure’s crucial role in society.Professor Estrada said: “Our modern society is a highly-interconnected one — and social groups have become ever-more interconnected as time has progressed, with the evolution from the cavemen to today’s technology-driven society.”Reaching consensus about vital topics — such as global warming, the cost of health care and insurance systems, and healthy habits — is crucial for the evolution of our society.”That is why the study of consensus has attracted the attention of scholars in a variety of disciplines, ranging from social to natural sciences, who have documented examples of peer pressure’s influence on popular cultural styles — such as changing fashions over time and the behavior of crowds at football matches — as well as collective decision-making, and even pedestrians’ walking behavior.”Professor Estrada’s research into how decisions are reached found that the process begins when individuals directly connected to each other first reach agreement, then — under the influence of peers not directly connected to them — the entire social group eventually tips into a collective consensus. He said: “Consider a teenager who is pressed by her friends into binge-drinking on a Saturday night — this corresponds to the direct pressure exerted by the peers connected to that individual.”However, she is also under indirect pressure, by seeing that many teenagers are doing the same every Saturday. Thus, this indirect pressure could make the difference in that individual to copy a given attitude.”Professor Estrada’s study, being published today in the Nature journal Scientific Reports, also examined the extent to which a small number of leaders can guide and dictate the behavior — and decisions — of an entire social group.He said: “Think about the existence of groups in different organisations, such as industries. Every organisation has one or more leaders who might, for example, be trying to convince the group to go to — or indeed not attend — a demonstration about a contentious issue.”The group can reach a consensus about the topic only by considering the direct pressure exerted by the members of the group and that of the leaders. However, if the individuals in the group observe that many other workers from external places have joined the demonstration, they can take a decision to join — regardless of the pressure exerted by their leaders.”In social groups in which indirect peer pressure is largely absent, the extent to which its leaders share the same views plays a critical role in the length of time it takes to reach agreement on issues. However, when there is strong indirect peer pressure, the role of the local leaders vanishes and individuals with no important positions in their networks can become the leaders of the group.Professor Estrada said: “Think about, for instance, the change of attitudes in respect to the smoking habit. In the 70s, it was very cool to smoke and you would see actors lighting cigarettes all the time on TV — and movie stars were always smoking at decisive moments in films.”Back then, individuals were not only directly pressed by their colleagues and friends to smoke but they also saw that people of the same social class, age and gender were doing the same. In this way, the combination of both direct and indirect peer pressure influenced the individuals to take up smoking.”What is happening right now is the reverse. …Read more
Apr. 22, 2013 — It’s not just about agriculture. Growing two crops a year in the same field improves schools, helps advance public sanitation, raises median income, and creates jobs.
New research finds that double cropping — planting two crops in a field in the same year — is associated with positive signs of economic development for rural Brazilians.
The research focused the state of Mato Grosso, the epicenter of an agricultural revolution that has made Brazil one of the world’s top producers of soybeans, corn, cotton, and other staple crops. That Brazil has become an agricultural powerhouse over the last decade or so is clear. What has been less clear is who is reaping the economic rewards of that agricultural intensification — average Brazilians or wealthy landowners and outside investors.
Leah VanWey, associate professor of sociology at Brown University and the study’s lead author, says her results suggest at least one type of agricultural intensification — double cropping — is associated with development that improves well-being for average rural Brazilians.
Looking at agricultural and economic data from the last decade, VanWey found that in municípios (counties) where double cropping is common, GDP and median per capita income were both substantially higher. Double cropping was also associated with higher quality schools and better public sanitation. “We looked at two indicators of private goods and two indicators of public goods,” VanWey said. “Overall, we find this really nice pattern of impacts on development associated with double cropping. These benefits seem to be widespread through the population.”
Meanwhile, intensification to single-crop fields from pasture with low stocking rates was not associated with development gains, the research found. VanWey says that is probably because double cropping is more labor intensive, which creates jobs, and more lucrative, which creates more tax revenue that can be invested in public goods. That was evidenced by a case study of two counties within Mato Grosso that was part of this new research.
“The community with the most double cropping also has a soy processing plant that employs thousands of workers as well as complementary poultry and swine raising and processing,” VanWey said. “In the long run there isn’t much money in just growing things and selling them, but processing allows the local area and workers to retain more of the per-unit cost of the final product.”
The findings are published in an issue of Philosophical Transactions of the Royal Society B focused on agricultural development in Brazil.
Mato Grosso has drawn much attention from scholars in recent years. It is not only the heart of Brazil’s agricultural production but also sits on the border of the nation’s cerrada (savanna) biome and the Amazon rainforest biome. Some evidence over the last decade suggests that even as agricultural production in the state has increased, deforestation in the Amazon region has slowed. For that reason, the state is seen by many as a model for agricultural development that minimizes harm to the environment.
To understand how land use is associated with economic development, VanWey teamed with John Mustard, professor of geological sciences at Brown, and Stephanie Spera, Mustard’s graduate student. Spera and Mustard used imaging from NASA’s Terra satellite to track land use changes in Mato Grosso from 2000 to 2011. They captured satellite images of the region every 16 days for a year. They looked for peaks in the greenness of the fields followed by a rapid loss of greenness, indicating the ripening and subsequent harvesting of a crop. Two peaks in greenness in the same year is an indicator that a field is double-cropped. Spera and Mustard recorded images from 2000 to 2001, and again from 2010 to 2011, to see how usage had changed over the decade. They found substantial increases in both single- and double-cropped fields.
VanWey then matched those data to local economic data, with the help of Brown undergraduates Rebecca de Sa and Dan Mahr.
The research showed that intensification to single-crop fields from pasture had no effect on economic variables. Double cropping, however, was associated with strong gains. For example, where double cropping was common, median income was substantially higher. According to VanWey’s calculations, median income for citizens of Mato Grosso would be decreased from 346 Brazilian reals per month (about $190) to 144 reals without the effects of double cropping. On the other hand, if all areas double cropped, monthly income would increase to 459 reals.
“[Double cropping] increases median incomes in an entire county, not just among people working in agriculture,” VanWey said. “So I’m arguing that it’s going to have these effects on the entire economy by providing employment that’s related to the agriculture.”
The positive association with public goods such as schools was strong as well. For that analysis, VanWey looked at a 10-point quality assessment scale used by the Brazilian government. She calculated that if all areas of Mato Grosso double cropped, scores on the assessment for public schools would increase from an average of 4.2 to 5.4.
The increases in measures of both personal wealth and public goods suggest widespread economic development associated with double cropping, VanWey concludes. However she’s not yet ready to advocate for public policy steps like blanket subsidies for double cropping. More research needs to be done, she says, to find out why double cropping thrives in some places but not others.
She and her colleagues are working on those questions now.Read more