Tanzanian President Jakaya Kikwete, though, says his government will continue with plans to build the 33.5-mile (54-kilometer) road through the park. Kikwete said the road will remain unpaved and that Tanzania "will do nothing to hurt the Serengeti."
Environmentalists are vigorously fighting the planned road, saying it will jeopardize the 2 million wildebeests and zebra who migrate in search for water from the southern Serengeti north into Kenya's adjacent Masai Mara reserve. The road, they warn, will lead to the downward spiral of an irreplaceable ecosystem.
Kikwete has given no ground, though. He said in a statement Wednesday that "a global network of environmental activists" has mounted a "completely misinformed campaign" claiming the road will be paved.
But Dave Blanton, co-founder of the group Serengeti Watch, said he and other conservationists believe that if the road is built it will have to be paved eventually.
Serengeti Watch this month obtained a copy of an environmental and social impact study on the road that was completed for Tanzania's government. The copy was leaked to the group, Blanton said.
The study found that by 2015, 400 vehicles a day will cross the section of road that cuts across the Serengeti. By 2035, the report predicts that 3,000 cars a day will use the road, Blanton said.
"If you multiply that out by 365 days a year that's a million vehicles a year, so they have clear plans for a major commercial route between Lake Victoria and the Indian Ocean," Blanton said. "I think common sense would say with that volume of traffic there is no way you could have a dirt road on top of that soil. Paving and fencing is the future. No one doubts that."
The environmental impact study found that an upgraded road "may impact the migration of the wildebeest and this would diminish the unique value of the Serengeti as a world heritage site." The study also said that endangered black rhinos could be negatively affected. Conservationists say that road collisions and deaths will increase dramatically.
The study also said employment and investment opportunities would increase. It said the road would be a boost to tourism, a finding that conservationists disagree with.
The road crossing the Serengeti is part of a planned 260-mile (420-kilometer) route between Arusha, near Mount Kilimanjaro, and Musoma, on Lake Victoria. Tanzania says the road is needed to connect the country's west with commercial activity on the eastern coast.
"We will continue with our serious efforts of conservation, but we cannot deny these people living on the northern side of the Serengeti border a road. There is neither justification nor explanation for not building this important road," Kikwete said.
Critics say a new highway could just as easily be built through the southern parts of the park, connect even more people and not harm the migratory route.
Kikwete said a Tanzania-based World Bank official suggested that the bank would be willing to help fund a road on the southern side of the Serengeti, but Kikwete said that route would not help connect communities in the north.
Blanton said conservationists don't understand why Tanzania is continuing to push ahead with the northern road despite the international outcry, which has included a petition signed by 290 scientists from 32 countries. UNESCO has said the road could lead the Serengeti's being listed on the List of World Heritage in Danger.
"Why is this so important to them? Nobody seems to understand because it doesn't add up. They could do the southern road and accomplish basically the same thing," he said. "It really depends on that hidden motive, that huge unknown factor leading them on. Whether there's some big economic incentive or geopolitical scheme involved we just don't know."
On the Internet:
Serengeti Watch: http://www.savetheserengeti.org
Environmental report: http://tinyurl.com/693dzl2