Some estuaries and deltas improving

Posted by: Saving Water SA (Cape Town, South Africa) – partnered with Water Rhapsody conservation systems – 05 June 2010

With new research showing that the overall position of the world’s estuaries and deltas is starting to improve, WWF today announced the formation of a World Estuaries Alliance (WEA) to further advance and protect one of the most vital of ecosystems.

An estuary is a physically and chemically dynamic and complex ecosystem

“Where the rivers meet the sea has always been one of the most important of habitats for humanity, but we have done enormous damage to the vibrant life in estuaries,” said WWF International Director General James Leape in his World Environment Day announcement of the WEA in Shanghai, China.

“Now, the tide is coming in again. In many estuaries and deltas, species abundance is going up and pollution is going down. Where we have curbed our instincts to clear natural features for development or navigation, fisheries are returning.

“But some estuaries, particularly in the tropics, are not experiencing the same improvements, and the growing impacts of climate change are threatening to undo some of our progress. We need to work together to advance the best thinking in sustainable estuary development and protection.”

According to recently published historical reconstructions, species abundance in 12 temperate estuaries had declined to 25 to 45 per cent of pre-industrial levels by 2000, largely due to human interventions in river systems and estuaries.

Mr Leape today released research commissioned from the Zoological Society of London (ZSL) showing that global estuarine species abundance increased by 16 per cent over the 25 years to 2005, with bird species more than doubling and fish populations stable.

The research looked at the abundance of around 500 estuarine species in 110 estuary and delta systems around the world and will support an estuarine health index being included for the first time in the 2010 WWF Living Planet Report, to be released in October.

However, the overall good news masks severe issues in tropical estuaries, with a 43 per cent decline in overall abundance and a 74 per cent decline to 2002 in tropical estuary fish species numbers.

Areas of concern are the construction and use of river and marine infrastructure, with only a small proportion of major world rivers running free. Dams stand in the way of fish and other species migrations and disturb sediment flow patterns to estuaries. There is more difficulty in the maintenance of vital natural systems in estuaries with high populations, particularly where incomes are also low.

WWF will be taking a range of recommendations to the inaugural World Estuaries Alliance conference, starting tomorrow in Shanghai. They include stronger environmental regulation to protect estuarine ecosystems and closer cooperation between engineers and ecologists for the planning and operation of infrastructure in rivers and marine areas adjacent to their mouths.

Better understanding is also needed on the mechanics of estuarine decline and recovery and on the benefits of functioning estuarine systems and biodiversity to human well-being.

Source: WWF

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