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Views of Africa
SEPTEMBER 2005
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In Learn More the National Geographic magazine team shares some of its best sources and other information to expand your knowledge of our featured subjects. Special thanks to the Research Division.

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 Did You Know?  
 Related Links  
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 NGS Resources  

Did You Know?Did You Know?

Across the stubbled plains of Namibia and southern Angola, barren terracotta-colored circles known as fairy rings spot the desert landscape like confetti. The sight is simultaneously weird and wonderful, all the more so because after 30 years of research scientists continue to scratch their heads in bewilderment, unable to explain the cause or purpose of the rings.
 
Several theories have been advanced over the years to unravel the mystery of the circles, which range in diameter from 6.5 feet to nearly 40 feet (2 to 12 meters) and are edged by densely growing grass. One theory held that radiation inhibited plant growth, while another suggested previous flora had poisoned the earth. Both were dispelled in 2000, when a group of scientists working under laboratory conditions grew plants in soil taken from the barren patches.
 
Another theory, proposed in 2001 by C. F. Albrecht from Stellenbosch, South Africa, suggests that termites living deep underground release a chemical that kills the grasses above. But why would termites kill off large patches of potential food? For another important element: water. Rainfall pools in the depression of each circle, then stays in the soil rather than being depleted by plants. Albrecht and his team found that after heavy rainfall, soil inside the fairy rings contains five times the water content of soil outside.
 
Even Albrecht's theory is being contested. While he claims the barren patches are dynamic, meaning they go bald, grow over again, and move around, others insist they are stationary, undergoing little change from decade to decade. A study published in 2004 by M. W. van Rooyen from the University of Pretoria in South Africa examined all previously conducted surveys and discounted each one, including Albrecht's. Rooyen's team also stated that their own soil-moisture measurements were inconclusive.
 
For now, it seems the raw wilderness of Namibia will keep its secret.
 
—Jennifer Chin

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Related Links

Megaflyover Site
megaflyover.org/about
Log on to the Wildlife Conservation Society's official Megaflyover website.
 
Megaflyover Blog
magma.nationalgeographic.com/ngm/megaflyover/index.html
Learn about Mike Fay's aerial survey project, see pictures, and read the blog he kept during the survey.
 
Wildlife Conservation Society Human Footprint Project
wcs.org/humanfootprint
Learn about the Human Footprint project, which maps humanity's impact on the globe. Mike Fay plotted his aerial survey route around this mapping project.
 
Terrestrial Ecoregions of the World
worldwildlife.org/science/data/attributes.cfm
Find the science behind how the World Wildlife Fund (WWF) defines, structures, and maps ecoregions.
 
Afrotropic Terrestial Ecoregions
nationalgeographic.com/wildworld/profiles/terrestrial_at.html
This page lists and describes all the ecoregions that the WWF has mapped within Afrotropic Africa.
 
World Wildlife Fund Global 200 Ecoregions
panda.org/about_wwf/where_we_work/ecoregions/ecoregions.cfm
Here the WWF provides information on the 200 ecoregions in most need of conservation and protection.
 
NamibRand Nature Reserve, Namibia
namibrand.com
Find information on this fascinating reserve in Namibia, featured in the article.

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Bibliography

Africa Environment Outlook. United Nations Environment Programme, 2002.
 
Burgess, N., and others. Terrestrial Ecoregions of Africa and Madagascar: A Conservation Assessment. The World Wildlife Fund Island Press, 2004.
 
Groombridge, Brian, and Martin D. Jenkins. World Atlas of Biodiversity: Earth's Living Resources in the 21st Century. University of California Press, 2002.
 
Pulse of Africa: Surveying Africa. BBC Focus on Africa. January-March 2005, 35-7.
 
Sanderson, E. W., and others. "The Human Footprint and the Last of the Wild." BioScience (October 2002), 891-904.
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NGS Resources

Fay, J. Michael. "Gabon's Loango National Park: In the Land of the Surfing Hippos." National Geographic (August 2004), 100-27.
 
Goodall, Jane. "Fifi Fights Back." National Geographic (April 2003), 76-89.
 
Quammen, David. "Jane: In the Forest Again." National Geographic (April 2003), 90-103.
 
Fraser, Sean. African Adventure Atlas. National Geographic Books, 2003.
 
Montaigne, Fen. "Water Pressure." National Geographic (September 2002), 2-33.
 
Godwin, Peter. "Without Borders: Uniting Africa's Wildlife Reserves." National Geographic (September 2001), 2-31.
 
Quammen, David. "End of the Line: Megatransect, Part III." National Geographic (August 2001), 74-103.
 
Lange, Karen E. "Djénné, West Africa's Eternal City." National Geographic (June 2001), 100-17.
 
Quammen, David. "The Green Abyss: Megatransect, Part II." National Geographic (March 2001), 2-37.
 
Morell, Virginia. "The Blue Nile: Ethiopia's Sacred Waters." National Geographic (December 2000), 2-29.
 
Quammen, David. "Megatransect: Across 1,200 Miles of Untamed Africa on Foot."National Geographic (October 2000), 2 -29.
 
Hoffman, Hiller J. "The Rise of Life on Earth—When Life Nearly Came to an End: The Permian Extinction." National Geographic (September 2000), 100-13.
 
McRae, Michael. "Central Africa's Orphan Gorillas: Will They Survive in the Wild?" National Geographic (February 2000), 84-97.
 
Ward, Logan. "Gorillas in the Aftermath." National Geographic Adventure (Spring 1999), 61-4.
 
Fay, Michael, and Michael Nichols. "Forest Elephants." National Geographic (February 1999), 100-13.
 
Chadwick, Douglas H. "Place for Parks in the New South Africa." National Geographic (July 1996), 2-41.
 
Chadwick, Douglas H. "Ndoki—Last Place on Earth." National Geographic (July 1995), 2-45.
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