Zimbabwe's policy of redistributing land owned by white commercial farmers threatens "ecological disaster", according to an eminent conservationist.

Professor Johan du Toit, of Pretoria University, South Africa, says it is "inevitable that wildlife populations will be overhunted" if the farms are handed over immediately to black Zimbabweans.

He warns that the country's black rhinos, one of the species that attracts high-spending foreign tourists and hunters, will be at great risk.

But he believes international help could avert the disaster.

Wildlife danger

Professor du Toit, director of the Mammal Research Unit at Pretoria University, says commercial white-owned farms in Zimbabwe are home to many rare large mammals, including cheetah, black rhino and sable - a type of antelope.

He told BBC News Online: "White-owned commercial farmland and ranchland in Zimbabwe supports a very significant proportion of that country's biodiversity.

"It will be severely impacted if this land is thrown over to subsistence agriculture."

The Zimbabwe Government insists that only about 30% of white-owned land is actually used for farming.

But the professor dismisses this, saying most of the arable land is cultivated already, while the rest supports indigenous woodland that is used for grazing cattle, or for wildlife, or both.

"The issue is that dumping impoverished peasants on geometrically-plotted patches of virgin non-arable land, without any infrastructure, tillage equipment, venture capital, housing, water supplies, or training will result quite simply in an ecological disaster," says Professor du Toit.

"Wildlife populations will be overhunted and snared, habitat loss will be rapid, and the whole crisis will just get exponentially worse."

Uncertain future

Professor du Toit acknowledges that Zimbabwe itself cannot afford to provide that sort of infrastructure. But he believes the international community would assist if the land redistribution was drawn up transparently and if the government completely revised its policy.

He believes Zimbabwe can still find a solution. But if it fails to do so, he thinks the future is bleak.

"We're going to lose some large populations and some important gene pools in the near future," says Professor du Toit.