24-05-2004, 12:25 PM
Alternatively this thread could be called the 'lesser of two weevils', or 'it's grown hyacinth yesterday'.
At: http://www.guardian.co.uk/internati...1223065,00.html
It shows what happens went you try to manage one ecological cock-up by eco-friendly means, but only succeed in setting off another mess.
quote:
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Malawi's beetle 'cure' triggers new weed
Attempts to halt the choking spread of water hyacinth have spawned even more aggressive vegetation
Rory Carroll in Mangochi
Monday May 24, 2004
The Guardian
Malawi was not picturesque enough for the anonymous European settler suspected of importing water hyacinth a century ago. Now the legacy of that decision is all too clear as power cuts ravage the economy.
As mats of weed flow down the Shire River, Malawi's electricity stops, crippling industry and costing the country half a million pounds a day.
Stretched in bunches more than 100 miles upstream from the Nkula hydro-electric station, was one such culprit, floating vegetation never meant for Africa. It is not hyacinth, but a highly invasive plant spawned by the battle against the hyacinth.
"The vegetation is getting worse. It's blocked the whole barrage," said Wales Kalombola, a technician from the Electricity Supply Corporation.
He stood on a dam in Liwonde, known locally as a barrage, which regulates the river for the Nkula plant. But the weeds block the flow.
Every day a crane hauls out tonnes of the gunk, and four trucks shuttle it to a site for burning. A second crane is due this month, said Mr Kalombola, as are a further six trucks.
The authorities are considering buying a floating bulldozer and harvester from Aquarius Systems, a US firm which battles the super weeds.
"They're struggling. It's coming down river faster than they can remove it," said Jane Dauffenbach, the firm's president.
Disruptions of hydro-electric power, which account for most of Malawi's 355MW, cost £188m a year, a third of GDP, says the energy ministry.
Soil erosion and silt clogs the rivers, as does hyacinth - a bitter twist because for a time the evil weed seemed vanquished.
The floating mass which can double in size in a fortnight, proliferated across the Shire until the mid-1990s. Blocking sunlight and sucking oxygen and nitrogen from the water, the plant increased acidity and damaged algae and plankton.
Unchecked it would have been an ecological disaster for Lake Malawi, the third biggest in Africa. Fishing villages with no alternative source of income faced ruin.
"In some areas 60% of the beach was no longer accessible," said Alexander Bulirani, deputy director of fisheries. "And crocodiles hide in the hyacinth, so it wasn't safe for women to collect water."
The weed came from Brazil and so, with help from Britain's department for international development, did its nemesis: Neochetina aerchornae and Neochetina bruchi, two beetles which eat only hyacinth.
Some 500,000 were released but although the hyacinth stood no chance, Malawi has found a malign side to the weevil solution.
Feeding on the decaying leaves and branches has come a new breed of hippo grass and papyrus, more aggressive than traditional vegetation, said Patrick Phiri, a district fisheries officer in Mangochi.
"Just as we were winning the battle against hyacinth we realised this problem of secondary growth," he said.
Back in Liwonde, Mr Kalombola confirmed that the weeds which snagged the turbines had become worse since hyacinth largely disappeared.
Malawi's only option was a combination of biological, chemical and mechanical means to control the hyacinth's revenge. "This will be a long-term programme, probably forever."
At: http://www.guardian.co.uk/internati...1223065,00.html
It shows what happens went you try to manage one ecological cock-up by eco-friendly means, but only succeed in setting off another mess.
quote:
--------------------------------------------------------------------------------
Malawi's beetle 'cure' triggers new weed
Attempts to halt the choking spread of water hyacinth have spawned even more aggressive vegetation
Rory Carroll in Mangochi
Monday May 24, 2004
The Guardian
Malawi was not picturesque enough for the anonymous European settler suspected of importing water hyacinth a century ago. Now the legacy of that decision is all too clear as power cuts ravage the economy.
As mats of weed flow down the Shire River, Malawi's electricity stops, crippling industry and costing the country half a million pounds a day.
Stretched in bunches more than 100 miles upstream from the Nkula hydro-electric station, was one such culprit, floating vegetation never meant for Africa. It is not hyacinth, but a highly invasive plant spawned by the battle against the hyacinth.
"The vegetation is getting worse. It's blocked the whole barrage," said Wales Kalombola, a technician from the Electricity Supply Corporation.
He stood on a dam in Liwonde, known locally as a barrage, which regulates the river for the Nkula plant. But the weeds block the flow.
Every day a crane hauls out tonnes of the gunk, and four trucks shuttle it to a site for burning. A second crane is due this month, said Mr Kalombola, as are a further six trucks.
The authorities are considering buying a floating bulldozer and harvester from Aquarius Systems, a US firm which battles the super weeds.
"They're struggling. It's coming down river faster than they can remove it," said Jane Dauffenbach, the firm's president.
Disruptions of hydro-electric power, which account for most of Malawi's 355MW, cost £188m a year, a third of GDP, says the energy ministry.
Soil erosion and silt clogs the rivers, as does hyacinth - a bitter twist because for a time the evil weed seemed vanquished.
The floating mass which can double in size in a fortnight, proliferated across the Shire until the mid-1990s. Blocking sunlight and sucking oxygen and nitrogen from the water, the plant increased acidity and damaged algae and plankton.
Unchecked it would have been an ecological disaster for Lake Malawi, the third biggest in Africa. Fishing villages with no alternative source of income faced ruin.
"In some areas 60% of the beach was no longer accessible," said Alexander Bulirani, deputy director of fisheries. "And crocodiles hide in the hyacinth, so it wasn't safe for women to collect water."
The weed came from Brazil and so, with help from Britain's department for international development, did its nemesis: Neochetina aerchornae and Neochetina bruchi, two beetles which eat only hyacinth.
Some 500,000 were released but although the hyacinth stood no chance, Malawi has found a malign side to the weevil solution.
Feeding on the decaying leaves and branches has come a new breed of hippo grass and papyrus, more aggressive than traditional vegetation, said Patrick Phiri, a district fisheries officer in Mangochi.
"Just as we were winning the battle against hyacinth we realised this problem of secondary growth," he said.
Back in Liwonde, Mr Kalombola confirmed that the weeds which snagged the turbines had become worse since hyacinth largely disappeared.
Malawi's only option was a combination of biological, chemical and mechanical means to control the hyacinth's revenge. "This will be a long-term programme, probably forever."