What’s the use of wetlands?

The black bog had him by the feet; the sucking of the ground drew on him, like the thirsty lips of death. […] he tossed his arms to heaven, and they were black to the elbow, and the glare of his eyes was ghastly. […] Scarcely could I turn away, while, joint by joint, he sank from sight.

Lorna Doone, R.D. Blackmore

A view over “Doone Valley”

What do you think of when you think about wetlands: ponds, lakes, streams, rivers? Humankind needs water to drink, irrigate crops, and clean ourselves.  However, our view of water tends to focus on the negatives: drowning, dirt, disease, and decay.  Words like “bogged-down” and “swamped” have entered everyday use. In some ways Carver Doone’s plight represents the fears that we have about wetlands. But I want to make the case that these wetlands are misunderstood heroes of the natural world.

For example, it is highly unlikely that, as he sank to his demise within a bog on Exmoor, Carver Doone was contemplating the contribution that he was making to carbon sequestration.  By this process the carbon that contributes to global warming can be locked away in soils and sediments, reducing atmospheric levels and cooling the planet.  In 2008, researchers from Iowa State University in the US reported that farm ponds could bury up to four times as much carbon as all of the world’s oceans.  Scientists are currently working on ways to exploit this process to control the amount of carbon in the atmosphere.

Furthermore, had Mr Doone taken the time to take in his surroundings, he might have noticed some of the diverse and interesting plants and animals that live in bogs and upland mires.  He may have been lucky to spot the narrow-bordered bee hawk-moth, Hemaris tityus, a species of moth that closely resembles a bumblebee.  This mimicry helps to deter predators who have learned that bees fight back.  He might also have noticed the round-leaved sundew, Drosera rotundifolia (pictured here), a carnivorous plant that secretes a sticky, sweet substance to attract insects which it then consumes. And this is just in England’s upland bogs – the variability of types of water bodies, from large lakes to small ponds, and icy tarns to balmy lagoons, lead to a similar variability in the types of animals and plants that dwell within them.

Taylor Creek site 6As he sank deeper, our unfortunate antagonist might have begun to appreciate just how much water can be stored in these wetlands.  The capacity to hold back large volumes of rainwater before letting it flow into major river channels is the natural flood defence.  Where we suffer most from flooding it is often where we have removed the local wetlands and increased the rate at which water moves into rivers by paving and concreting over natural habitats. Urban planners have realised this and “sustainable urban drainage systems” (SUDS) are now a mandatory part of all new buildings.

It is quite likely that our now neck-deep naturalist would be aware of the stench arising from water.  Part of this would be the manure that had washed into the water from the animals grazing the surrounding land.  Manure, as well as artificial fertiliser, can cause major problems when it leaves farms and enters water courses.  There is even evidence to suggest that Australian farmers are contributing to the decline of the Great Barrier Reef, as their agricultural chemicals are carried away along rivers and swept out to sea.  There, the chemicals cause ecological changes which help an aggressive species of starfish (the “crown of thorns”) which consumes huge amounts of coral. Wetlands such as ponds and lakes provide a filter that can remove these sources of pollution, storing them in sediments.

Of all the benefits afforded by wetlands, that which would be least likely to appeal to our soon-to-be-engulfed ecologist at this particular point in time is just how pretty it is. Seventeenth century England was a far greener land than that in which we live today.  Now it is common for schoolchildren to experience the natural world only through television and books, and for inner city communities to be devoid of green space.  School ponds, urban rivers, and park lakes can all help to bring some aspects of the natural world to our doorsteps.

While we are sometimes tempted to see the natural world as something to be tamed, it is important to realise that there is great value in nature.  Carver Doone may not have appreciated any of these “ecosystem services”, but then he was a murderous lunatic. Indeed, wetlands such as bogs, lakes, and even the humble garden pond play their part in helping to fight climate change, prevent flooding, reduce pollution, enhance biodiversity, and connect us to the natural world.  So do your part: dig a pond!

Photo credits:

  • Doone Valley by IDS.Photos
  • Peat bog pond by John Phoenix
  • Sundew by Petr Dlouhý
  • Taylor Creek stormwater facility by me!
  • Great Barrier Reef photo was taken from the International Space Station
  • Central Park Lake by “Urban” on Wikimedia

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