Healthy wetlands have many values for people and other species. However one littlle mentioned value which WetlandCare Australia remind us is their value as a storage or sink for the greenhouse gas carbon dioxide.
The world is putting too much emphasis on planting trees to reduce the effects of climate change, according to WetlandCare Australia. A report in New Scientist magazine on 3 May 2008 has identified that restoring drained peat wetlands is better at removing carbon dioxide from the air than planting trees.
World Environment Day on 5 June 2008 has the theme of kicking the CO2 habit for a low carbon economy.
"Reducing our use of coal and petroleum is the most important thing we can do, but its worth remembering that many wetlands are effective carbon sinks," said Alan Cibilic of WetlandCare Australia. "After all, most oil reserves came from coastal waters and lakes in the first place. Wetlands are amongst the most productive ecosystems on earth, and the story gets better. When wetland plants die they sink below the water table where there's little oxygen, so they don't easily rot. These anaerobic conditions are ideal for long term carbon sequestration."
The New Scientist report identifies that carbon does leak back into the atmosphere from wetlands, mainly as methane, which is around 25 times more potent than CO2 as a greenhouse gas. Mr Cibilic points out that even if that is significant, peat restoration is still likely to be more effective than tree planting.
Mr Cibilic said that one of the main benefits of restoring wetlands comes from reversing the effects of drainage - in drained wetlands the organic matter oxidises, or rots, as air gets into it, and this releases carbon dioxide.
WetlandCare Australia has highlighted the need for more funding to research carbon sequestration in wetlands, and is urging the inclusion of wetland sequestration in any future scheme to accredit the sequestration of carbon in soil.
"This would have the added benefit of giving wetland owners an alternative income stream. That way farmers could reduce grazing pressure on wetlands at the same time as they reverse drainage, further improving the productivity and habitat value of wetlands," said Mr Cibilic.
"Planting trees will help remove carbon dioxide, which is great, especially if you're also reinstating native ecosystems. But plantations on drained wetlands are definitely to be avoided. Restoring such wetlands will provide more long term benefits for the planet."
Wetlands are among the most productive ecosystems in the world, yet their extent and health continues to diminish. Many wetlands have been degraded or destroyed completely in the past 200 years.
Wetlands are particularly vulnerable due to the pressures from unsustainable land use activities, and the increasing pressure of population and development along our waterways.
The benefits wetlands contribute to all of us are significant. In fact, the ecosystem services wetlands provide underpin much of our economic activity. The assumed to be "free" services provided by wetlands are taken for granted and include:
Flood detention basins which reduce the impacts of flooding
Fish nursery and habitat areas
Drought refuges for stock and wildlife
Nutrient capture and recycling
Filtering and capture of sediment
Significant habitat areas for wildlife - quality of life & ecotourism contribution
Great places to look at and visit - quality of life & ecotourism contribution
Waterway, riparian, and habitat connections between other natural areas - quality of life & ecotourism contribution
More imformation is available from the website http://www.wetlandcare.com.au