The destruction of wetlands began more than a thousand years ago
humans may be blamed for destroying ecosystems, but in the case of wetlands, they may not be responsible. A recent study reveals that a wetland area in Lancashire, uk, began drying out long before the first human was born. David Wilkinson of Liverpool John Moores University and his colleague Stephen Davis studied the history of Astley Moss, a wetland area near Leigh.
They examined the tiny shells of microorganisms called testate amoebae that can live for thousands of years buried under the soil. Based on the fact that different species of testate amoebae need different amounts of moisture to survive, the researchers used the different type of shells found, as an indicator of the past water levels. On combining the result of their findings with radiocarbon dating of soil samples, they discovered that the Astley Moss had started drying two thousands years ago. "The first big change in Astley appears to be due to climate rather than people," says Wilkinson ( New Scientist , Vol 166, No 2236). He adds that Sphagnum mosses of Astley had started declining in late 19th century because of the air pollution from Manchester. Sphagnum mosses thrive in waterlogged environments which eventually leads to the formation of wetland areas.
The researchers presented their findings recently to a joint meeting in Orlando, Florida, of the Ecological Society of America and the British Ecological Society. These findings may provide conservationists with a new insight, that there is not only one natural state for an ecosystem that should be restored. "Conservation planning surely has to deal with the complications of such findings," says Wilkinson. He pointed that studies of ancient pollen show that the bare areas of today were once covered by trees.
"These findings give an interesting edge to the work we are doing," says Mick Weston of Lancashire Wildlife Trust, which is trying to restore Astley Moss by blocking drainage ditches and cutting down trees.
Many wetlands have been drained for agriculture, mined for peat and damaged by pollutants. In recent years wetlands have been considered as a vital habitat for unique plants such as insect-eating sundews and conservationists have tried to make them wetter in an attempt to restore them to their natural state.
"I think the use of testate amoebae in peatland restoration has great potential, but only half a dozen scientists are currently doing this type of research," says Barry Warner, director of the Wetlands Research Centre at the University of Waterloo in Ontario.
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