A proposed road through Tanzania's Serengeti National Park will lead to the collapse of an ecosystem celebrated for its vast herds of wildebeest and zebra, scientists warn.
"The road will cause an environmental disaster by curtailing the migration of wildebeest," said an opinion piece published this week in the journal Nature and signed by 27 researchers around the world.
"Migratory species are likely to decline precipitously, causing the Serengeti ecosystem to collapse, and even flip from being a carbon sink into a major source of atmospheric carbon dioxide."
Construction of the two-lane road is slated for 2012 to provide truck traffic with a link from Tanzania's coast to Lake Victoria and Uganda, Rwanda, Burundi and Congo.
The proposed route cuts through 53 kilometres in the northern end of the park, a United Nations World Heritage Site because of its rich ecology.
The route also crosses the path used by 1.5 million wildebeests and zebras as they travel north in search of food and water during the dry season.
Collisions between animals, vehicles and humans can be expected, the scientists said. And the threat of collisions will likely lead local officials to build a fence, as was done in Canada's Banff National Park to prevent collisions with animals such as elk, the article added.
But University of British Columbia zoologist Anthony Sinclair, one of the three lead authors of the article, said wildebeests don't know how to deal with fences.
'If we lose that … then the whole Serengeti disappears as we know it.' — Anthony Sinclair, UBC zoologist
"They run straight into them," he told CBC's Quirks & Quarks in an interview scheduled for broadcast Saturday. "They pile up against the fence and … they just push further forward until the whole lot of them get crushed."
Wildlife overpasses that are used to reduce animal collisions in Banff are not an option in the Serengeti, the Nature article said. They would cost millions of dollars and could never accommodate the huge migrating herds of Serengeti animals.
"We can travel for as much as 60 kilometres through those herds, non-stop, seeing wildebeest from horizon to horizon," Sinclair said. "It's truly one of the great natural wonders of the world."
If the wildebeest can't get to their dry-season food and water sources, at least half can be expected to disappear, causing large changes to the ecosystem, Sinclair added. Wildebeest eat grass, preventing it from burning and allowing trees to grow. They travel with other herbivores such as zebras and provide food for carnivores such as lions.
"The whole system is basically linked to the wildebeest," Sinclair said. "It's what we call a keystone species. If we lose that as a keystone, then the whole Serengeti disappears as we know it."
Alternative route proposed
The researchers propose a road route running south of the national park, which they said would minimize damage to the ecosystem and serve five times as many people.
But the Tanzanian government says the existing plan for the road, which would fulfil a campaign promise made by President Jakaya Kikwete in 2005, is still on course, despite opposition from conservationists, the Citizen, a newspaper based in Dar es Salaam, Tanzania, reported on its website Friday.
Kikwete is running for re-election on Oct. 31.