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Savanna model tracks delicate balance in Africa
As the human population grows and native species decline in eastern Africa, scientists have developed a tool that may help land managers reverse these trends, saving wildlife and people.
Scientists from Colorado State University and the Nairobi-based International Livestock Research Institute spent 15 years developing a computer model they call "Savanna."
"Savanna is helping us to sort out how much ecosystem change is due to natural processes versus human influence," said Mike Coughenour, a senior scientist at the Natural Resources Ecology Laboratory at CSU. "The model helps us to find a way to save the elephants without driving marginalized people into further poverty."
By representing the processes that give rise to changes in the ecosystem, Savanna is more comprehensive than most computer models. Using hundreds of variables in wildlife, plants, livestock, soil, climate and human activity, Savanna can make predictions from five to 100 years into the future. While most models are static, capturing a single point in time, Savanna shows the interaction of different processes over a duration.
Kenya's population, now 29 million, has tripled since 1960, and some of the fastest-growing areas are adjacent to wildlife reserves. For centuries, the Maasai, the predominant cattle-herding people in eastern Africa, used livestock management techniques that balanced the well-being of the region's wildlife.
Given a choice, many pastoral communities in eastern Africa would continue to raise cattle. But grazing areas have been greatly reduced, and disease in cattle herds is common. Many herders have turned to farming.
The population that surrounds the Maasai Mara National Reserve in Kenya is growing at an annual rate of 7 percent. In the past 15 years, cultivated land in the same area has increased from 1 percent to 10 percent. According to the researchers, wildlife in and around the reserve declined by 60 percent between 1977 and 1994.
Grasslands that once supported wildlife are now fields for crops. Battle lines are drawn between farmers and wildlife.
The savanna model will help governments, tribal leaders and private groups determine how and where farming, cattle-grazing and wildlife can co-exist, the researchers say.
Many tribal leaders want the same information that government officials have in order to participate in decisions about land use, they note
The researchers will offer training sessions for East Africans to demonstrate how the savanna model can project the outcome of various decisions on land use.
"The model cannot be used to change policy directly, but it can be used by people to argue their interests, " Coughenour said.
"This is a decision-making planning tool that is helping us to develop management practices that are more equitable for both wildlife and people," he said.
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