At first it seemed a paradise. Baboons played on the dusty track ahead of us. Impala and zebra, wildebeest and spiral-horned kudu bounded into the bush as our vehicle approached. We stopped to admire a 3,000-year-old baobab tree with a trunk that dwarfed our four-wheel drive, and spotted a herd of African elephants. It seemed scarcely possible that this semi-arid land in the Lowveld of southeastern Zimbabwe could support so much wildlife.
It was only as we approached the eastern edge of the million-acre Save Valley Conservancy that we began to encounter the problems besetting this idyll. "Resettled farmers" had moved in - burning trees, building huts of mud and thatch, and clearing land in an improbable attempt to grow crops.
Soon Clive Stockil, chairman of what is the biggest private conservancy in Zimbabwe, turned off the track and stopped. We were hit by the stench of rotting flesh. A few yards away was the decomposing carcass of a black rhinoceros, one of the world's most endangered species, shot by poachers three days earlier.
In life this 15-year-old bull was a magnificent creature weighing a tonne. Now it had been stripped of its meat by hungry villagers, writhing maggots feasted on the contents of its belly and clouds of flies hovered overhead. Its head was intact except where its second horn had been hacked off. That was what the poachers had been after because, thousands of miles away in eastern Asia, rhino horns are prized for their alleged medicinal value and fetch a small fortune.
What made this rhino's death even more tragic was that the conservancy had removed its horns last year to stop it becoming a target for poachers. The horns for which it was shot were regrown stumps barely two inches long. The same was true of the young female rhinoceros whose remains festered near by in the summer heat. Her horns were also mere stumps.
The cow was in season and the pair were probably in the process of mating when they were slaughtered. "You feel angry. You feel bitter. You have the urge to get even," Mr Stockil said. "It sounds silly to say, but it's almost like a member of my family. I can recall when she was born and watching her give birth, and giving birth again 28 months later, and you come here and see this.
"My tears, they came down," added Jackson Kamwe, head of the conservancy's rhino surveillance unit, recalling the moment he found the corpses. The conservancy knows its rhinos so well that it even has names for them. The bull was Enoch, the cow Gladys.
Sadly, this massacre was far from isolated. Last month poachers used an AK47 to kill Ice, a young cow whose mother, Natalia, was shot in 2007. This year 16 black rhinos have been killed in Save, and Mr Stockil admits that he is losing his battle to protect the 120 others that the conservancy has nurtured so lovingly since it was established in 1991.
Nor is this "onslaught" confined to Save. In the past two years criminal syndicates have begun targeting the rhinoceros. Experts believe that between 50 and 100 black rhinos have been shot in Zimbabwe this year, twice as many as last year, and between 50 and 60 in neighbouring South Africa - up from 30 in 2007. There were once hundreds of thousands of the rhino, with their distinctive prehensile upper lips, across Africa. Today there are barely 4,000. One of the four sub-species was declared extinct in 2006. The rest have been designated "critically endangered" and Mr Stockil says that "the countdown to extinction" has begun.
Zimbabwe's hunger, poverty and collapsing law and order make it a particularly soft target for the syndicates, and nowhere more so than Save.
Some 10,000 "resettled farmers" have seized a quarter of the conservancy in recent years, giving them easy access to the rhinos' habitat. Like millions of other Zimbabweans, they are destitute and starving, making it easy for the syndicates to recruit poachers and guides for paltry fees.
When the poachers are caught, the syndicates use their wealth to subvert justice. Not one Zimbabwean rhino poacher has yet been prosecuted successfully. Many are caught, freed and return straight to poaching.
The three men who killed Enoch and Gladys are good examples. They had removed just one of the pair's four stumpy horns before they were surprised by Mr Kamwe and his scouts. They ran away but the scouts recognised two. They had been arrested for killing another black rhino earlier this year but somehow managed to "escape" - unseen and unhandcuffed - from the police van taking them to court.
Save goes to great lengths to protect its rhinos. It employs a scout for every 20sq km (8sq miles), each armed and with radios. It has airdropped leaflets over villages bordering the conservancy offering $1,000 rewards for information about poachers, and has established a network of informers - one of whom alerted Mr Kamwe to the killing of Enoch and Gladys. It has built up dossiers on poachers and their firearms, micro-chipped each rhino, and sought to co-opt the surrounding villages by establishing a trust that would make them beneficiaries of its success.
It would like to do much more but it is hamstrung by another problem unique to Zimbabwe: the tourist trade on which the conservancy depends for its finances has collapsed.
Before the white farm seizures began in 2000, Mr Stockil's Senuko Lodge had an occupancy rate of more than 60 per cent. Today it is almost empty. "We're in a very serious financial crunch," says Mr Stockil who, in desperation, recently began catering for wealthy hunters of non-endangered species such as elephants. Without that, he says, "we would have had to close".
Mr Stockil believes, though, that no amount of scouts would be able to protect the rhinos over such a vast area, and that more drastic measures are needed.
The conservancy de-horns the rhinos that live nearest to the encroaching settlers to minimise their value to poachers but that has been ineffective: sometimes the poachers cannot even see a rhino's head before they shoot. He now wants all Zimbabwe's rhinos de-horned, and the wildlife authorities agree, but that would be vastly expensive, requiring helicopters, drugs, four-wheel drives and huge manpower. Moreover, it would have to be repeated every two years.
He believes that the poachers would still kill for mere stumps, and advocates an even more ambitious scheme that would destroy the five to ten syndicates behind the rhino poaching.
As Mr Stockil points out, the actual poachers are mere pawns - he knows of one who has made just enough to buy himself a motorbike. The real money is made by the middle men who spirit the horns across Zimbabwe's borders to South African ports and airports or up to the fast-growing Chinese community in Harare. From there they are shipped to the Far East, some in diplomatic bags. A Vietnamese Embassy receptionist in Pretoria was photographed recently taking delivery of a rhino horn from a dealer.
Mr Stockil wants African states to establish how many horns the end-users in China, Vietnam and North Korea require, to provide that number themselves, and to use the proceeds to protect the world's last black rhinos before they vanish forever. "You would stop poaching, raise money for conservation, increase the rhino population, do away with the illegal trade and provide a legal product that for centuries has been used by cultures that say they need it," he argues.
In the meantime the black rhino population is in danger of shrinking to a level that is barely sustainable, and at Save, and across Zimbabwe, poaching of all sorts is escalating rapidly as the human population grows hungrier.
Near Senuko Lodge two tall poles support 6,000 snares that scouts have discovered on the conservancy over the past six years. Today they are finding between 30 and 50 a week, the more recent made of copper stripped from telephone wires. A few are for rhino. Most are designed for impala and other "bushmeat" but they trap animals indiscriminately - giraffes, zebras, lions, cheetahs. The conservancy has put down half-a-dozen maimed elephants. But it is another highly endangered species, the carnivorous African wild dog or Lycaon pictus, that the snares threaten most.
There used to be half a million of these brightly coloured dogs in Africa, but they were hunted almost to extinction as vermin. Today there are fewer than 5,000. In three years Save's wild dog population has shrunk from well over 150 to barely 100.
The victims of Zimbabwe's implosion are not just its people. They include some of the world's rarest animals. The difference is that the human race will outlast Robert Mugabe.
THE MIGHTY FALLEN
65,000 rhino in Africa 35 years ago. Now there are an estimated 3,600
2,000 black rhino in Zimbabwe before the peak of poaching in the 1980s
370 at the lowest point in 1993
201,000 overseas vistors to Zimbabwe in 2005, down from 597,000 in 1999