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More rain leads to fewer trees in the African savanna

Single camel thorn acacia on the savannah in Etosha National ParkSingle camel-thorn acacia on the savannah in Etosha National Park. The Etosha Pan in in the background. Princeton University researchers might have finally provided a solution to the ecological riddle of why tree abundance on Africa’s grassy savannas diminishes in response to heavy rainfall despite scientists’ expectations to the contrary. The researchers found that the ability of grasses to more efficiently absorb and process water gives them an advantage over trees such as the acacia. Credit: © marietf / FotoliaIn 2011, satellite images of the African savannas revealed a mystery: these rolling grasslands, with their heavy rainfalls and spells of drought, were home to significantly fewer trees than researchers had expected. Scientists supposed that the ecosystem’s high annual precipitation would result in greater tree growth. Yet a 2011 study found that the more instances of heavy rainfall a savanna received, the fewer trees it had.

To this ecological riddle, Princeton University researchers might have finally provided a solution. In a study published in the Proceeding of the National Academy of Sciences, researchers use mathematical equations to show that physiological differences between trees and grasses are enough to explain the curious phenomenon.

The researchers found that under very wet conditions, grasses have an advantage because they can quickly absorb water and support high rates of photosynthesis, the process by which plants convert sunlight into energy. Trees, with their tougher leaves and roots, are able to survive better in dry periods because of their ability to withstand water stress. But this amounts to a disadvantage for trees in periods of intense rainfall, as they are comparatively less effective at utilizing the newly abundant water.

UNEP Head Launches New Resource Centre for UNEP Live Data Platform

By integrating big data gathered from sensors embedded in smartphones with satellite data, UNEP Live can support governments to tackle climate change and at the same time help cities reduce premature deaths caused by air pollution.

The head of the United Nations Environment Programme, Achim Steiner, has launched a new resource center in the organization’s Nairobi headquarters, aimed at training staff, Member States and interested parties on how UNEP Live, a new ‘big data’ analysis tool, can support decision-making and integrated assessments of the state, trends and outlooks of the environment.

UNEP Live weaves together the environmental and socio-economic data of the complex world we live in to create a big picture, showing not only how challenges are interlinked, but how addressing one problem can bring multiple benefits in other areas.

Exploit urinals for cheap fertilizer, says Indian inventor

Courtesy of Flickr for waterdotorgImage credit: Flickr/waterdotorgRecycling urine collected at public toilets is a cheap and simple way to produce fertilizer, according to the developer of a waterless urinal.

Human urine contains three nutrients — phosphorus, nitrogen and potassium — that are essential for plant growth, says Vijayaraghavan Chariar, a researcher at the Indian Institute of Technology Delhi.

Bill Gates on post-MDGs

When it comes to the next set of global development goals, Bill Gates has this to say: Why fix something that isn’t broken? In his 2013 annual letter released Jan. 30, the billionaire philanthropist noted that because of the progress made toward achieving the Millennium Development Goals,there is a lot of interest to expand them.

The MDGs, he said, were coherent, the groups that needed to work together on the goals were easy to identify and these groups could be held accountable for cooperation and progress. “But many of the potential new goals don’t have unanimous support, and adding many new goals, or goalsthat are not easily measurable, may sap momentum,” he said.

Developing an Affordable Sanitary Pad

Health need

Girls as well as women in the developing world suffer from lack of adequate solutions to manage menstruation. Imported pads are prohibitively expensive for low-income families. Research conducted in Uganda indicates that about 90 percent of urban poor women and girls cannot afford off-the-shelf sanitary pads and instead improvise with materials such as grass, leaves, old newspapers, and pieces of cloth. These materials, however, have been linked to certain reproductive tract infections.

They also have limited absorbency and make it difficult for girls to participate in school during their periods.




Current Issue: Africa Water & Sanitation & Hygiene November - December 2017 Vol.12 No.6