We are losing wetlands three times faster than forests, according to the Ramsar Convention on Wetlands. When it comes to restoring them to their natural state there is one hero with remarkable powers - the beaver. Wetlands store water, act as a carbon sink, and are a source of food. The Ramsar Convention on Wetlands says they do more for humanity than all other terrestrial ecosystems - and yet they are disappearing at an alarming rate. The main problems are agricultural and urban expansion, as well as droughts and higher temperatures brought about by climate change. But if you have a river and a beaver it may be possible to halt this process.