Long-term declines of elephants, giraffe, impala and other ‘common' animals in Kenya are occurring at the same rates within Kenya's national parks as outside of these protected areas, according to a study released this week.

"This is the first time we've taken a good look at a national park system in one country, relative to all of the wildlife populations across the whole country," said David Western, professor of biology at UC San Diego and the founding executive director of the African Conservation Centre in Nairobi, who headed the study. "And we found that wildlife populations inside and outside of the parks are declining at much the same rate."

The international green activists' campaign against construction of a highway in the Serengeti National Park has suffered a major blow - the head of state says the project will go on.

President Jakaya Kikwete, for the first time, said Tanzania would not stop the construction of a commercial highway linking Arusha and Musoma town through Serengeti National Park.

In his end-of-July speech to the nation, President Kikwete said the best the government could do is to leave the 50km stretch crossing through the wildebeest migration route untarmacked.

Slum tourism is taking off in Kenya. Several local organisations have started selling guided trips through Kibera, a short drive from the luxury hotels that serve most foreign visitors in Nairobi.

For about £20, tourists are promised a glimpse into the lives of the hundreds of thousands of people crammed into tiny rooms along dirt paths littered with excrement-filled plastic bags known as "flying toilets", as one tour agency explains on its website.

While Kibera has long been an obligatory stop for foreign dignitaries and film crews shooting movies such as The Constant Gardener, its addition to the tourist circuit has stirred debate.