Why we need to build more ponds

Ponds, rich in diverse and rare species, are vanishing from the British landscape - and your country needs you to replace them. It's time to get digging, says Sanjida O'Connell

Creating a pond in our garden was a fantastic way to impress the neighbours. Usually disapproving of our city ways, 70-year-old Albert's eyes lit up when he caught his first glimpse of a broad-bodied chaser. He'd never seen one of these fat, lilac dragonflies with their 7cm wingspans, despite living in the area all his life.

We were equally excited by the rapid colonisation of the pond: within a few months we had common newts, toads and another dragonfly species - an emerald and gold southern hawker - although admittedly we stole tadpoles from a school pond to kick-start the frog population.

According to Pond Conservation, the information and advice group, garden ponds are incredibly rich in wildlife - 75 per cent of our frogs live in urban areas. This summer, Pond Conservation launches its Million Pond Project, a nationwide drive to create new ponds, both in gardens and rural areas. It has already begun a pilot project to map every pond in the country.

Dr Steve Head, the director of Pond Conservation, is based at Oxford Brookes University. He says pond restoration is urgent, as we have lost more than two-thirds of our ponds in the past hundred years. Three thousand years ago, during the Iron Age, the situation was quite different: almost a quarter of the British countryside was a marshy quagmire of ponds and wetlands.

Much of the country has been drained, but we still have a few "pingos" left. These are ponds that formed during the last Ice Age when chunks of glaciers melted. However, of the 400,000 or so ponds in this country, only 2 per cent weren't artificially created.

More worrying is that at least half of our ponds are in a degraded condition. The main problems are climate change (including acid rain and hot, dry summers) and pollution, including run-off from roads and fields. High levels of phosphates and nitrogen from fertiliser lead to dense algal blooms in ponds, which burn up the oxygen and suffocate aquatic life.

Traditional uses for ponds have also disappeared now that animals have fresh water piped to them instead of using muddy ponds in the corners of fields, and we no longer need ponds for mills or factories. The prognosis is bleak, as existing ponds naturally become silted up and eventually disappear. To try to halt pond decline, the Million Pond Project is hoping to create ponds in the countryside. But, as Dr Head says: "We're happy to encourage people to put ponds in their gardens, too."

Although most British ponds are not "natural", they can house a rich diversity of wildlife. A newly created pond may look barren, but it can be home to creatures that are unable to compete with other species, particularly fish. A three- or four-year-old pond may have as much wildlife as a 50-year-old one.

Ponds can contain as many as 200 types of invertebrates, and they're havens for rarer animals, like voles and great crested newts. They can attract creatures that aren't normally associated with ponds: grass snakes, hedgehogs, foxes and badgers all like to drink at ponds, as do garden birds, and at dusk you may see pipistrelle bats hunting over them.

Pond Conservation's advice is that you simply leave your pond and see what appears. Charles Darwin was one of the first to notice how quickly animals and plants colonise bodies of water. We were far too impatient with our pond, rushing off to the nearest garden centre. But, as Head says: "Most people have gardens because they are beautiful, so if you put in a pond, plant what will make you happy and what will be good for wildlife."

The key to creating a rich diversity of wildlife is to think about the structure of the pond from an aquatic animal's point of view. Almost all pond animals live in the safety of dense vegetation, often in water only a few centimetres deep. The plants that provide the best habitats are those that create a diverse, complex structure at the water's edge, such as grasses and wetland herbs. Nor is there any need to create a lake in your back garden - a sunken washing-up bowl or a container as small as 20cm across is enough to attract pond dwellers.

The core of the Million Pond Project will be to discover where all our ponds are in the UK - a daunting prospect, as any pond over two square metres and up to two hectares in area is included. Hugh Roberts of Pond Conservation's northern branch, based in Leeds, has begun a pilot scheme in Lancashire. Over the next two years, local communities will be encouraged to work with a team of pond wardens to chart the region's ponds.

Lancashire is rich in ponds, given its industrial background, yet it has lost 10,500 of them in the past 100 years. Of the remaining 7,000, only 100 have any legal protection. Every one will be entered on a national database (the National Pond Monitoring Project), which will chart the location of each, and its population of plants and invertebrates.

"We need to know where our ponds are," Roberts says, "so that when we build new ponds we create them in clusters, which will enable animals and plants to travel between them."

The scheme will then be rolled out nationwide. The database is already up and running, and contains information on 500-600 ponds previously surveyed. The information is all publicly accessible, and anyone can enter data on ponds they know.

According to Dr Stewart Bryant, county archaeologist for Hertfordshire County Council: "The Million Pond Project is unique because it provides holistic guidance on the creation of ponds, as well as assessing their historical, archaeological and ecological importance."

One of his favourite sites is Berkhamsted Castle in Hertfordshire. The Norman castle is where William the Conqueror received the Saxons' surrender in 1066; the moat is home to the protected great crested newt.

Ponds preserve artefacts, such as leather and wood, that would otherwise rot, as well as pollen and insects, which can indicate how climate conditions have changed. Sediment from a 75,000-year-old natural oxbow pond near Peterborough showed that it contained most of the same species, such as yellow water lily and spiked water milfoil, that are found in artificially created ponds today.

"Our research has shown that networks of small ponds in the landscape may contain more diversity than stream and river habitats, yet they have far less legal protection," says Head. Almost all ponds currently classified as "high ecological quality" (in other words, containing key species or groups of species) harbour endangered wildlife, yet they are not covered by countryside legislation.

Head hopes that ponds will be awarded priority habitat status in April, affording them the same legal protection as chalk grassland and ancient woodland. "Ponds are, after all, the only place in the UK where you can lie on your stomach and look into a different world," he says.

The National Pond Monitoring Project (pondnetwork.org.uk); Pond Conservation ( www.pondconservation.org.uk); free booklet on creating a pond from www.english-nature.org.uk

How to make your own wildlife pond

* Choose a site that's partially in full sunlight and mark out the area with bamboo canes. A wavy-edged oval is a more natural shape.

* Avoid tree roots, and check the site plans of the house for pipes or cables.

* The bigger the pond, the more plants and animal species you'll have - but doubling the dimensions of a pond will increase the cost of the liner by four times and create eight times the amount of soil to dispose of.

* A large pond can be more easily excavated with a mini-digger. Half a metre is deep enough. Make sure that you create shallow sloping sides and plenty of shallow ledges.

* Clear the pond hole of any sharp stones, then cover with sand and old carpet before lining with butyl rubber.

* Bury the extra liner round the edge of the pond and cover with turf.

* Creating a beach of stones over a shallow (5cm or less) area, or a bog garden (line an area 30cm deep, then cover with soil) will add more diverse habitats.

* If you have children, don't allow them near the pond unsupervised. You can make the pond safer by fencing it in and putting strong mesh just below the surface of the water.

* Fill it, preferably with rain water.

* Take samples of plants from your neighbours' ponds but make sure they are native and not alien weeds.

* Make sure you have a cross-section of plants from three main types: submerged (eg water milfoil); floating (eg yellow water lily); and shallow water emergents (eg water forget-me-not).