Wildlife conservationists define ponds as `standing open water’ between 1 m² and 2 ha in area which hold fresh water for at least four months of the year; anything larger is termed a lake.

Ponds and lakes contribute greatly to the scenic beauty of the landscape, and are enjoyed by young and old alike. They also support an amazing variety of wildlife.

Around 3,500 of Britain's invertebrate species live in fresh water; of these, as many as half can be found in ponds. Over two thirds of Britain's Red Data Book freshwater invertebrate species occur in ponds, as do 300 species of wetland plants, including half of Britain's rarest wetland species. Larger lakes are of particular importance to bird life, for which some are internationally important as refuges, especially for ducks that winter in the UK such as gadwall.

Sadly, ponds and lakes have suffered a huge decline in numbers this century due largely to the effects of agricultural change, pollution and poor management.

New ponds and lakes are being constructed, but they are not equivalent in value to long-established bodies; furthermore, their design and stocking often discourages wildlife. Nevertheless, good examples can rapidly support rich wildlife populations, of pioneer species in particular.

The number of ponds in the South West is unknown, but is probably several thousand rather than tens of thousands..

In the South West, lowland still water areas of more than 5 ha make up a total of c4,100 ha, and this represents a small fraction of the UK total (c300,000 ha). The tables below name important ponds and lakes in the region.

The following are examples of species that depend on ponds and lakes, some of which are of conservation concern:

Ponds and lakes face a huge range of problems, many of which reflect the changing way our countryside is farmed. The UK total is estimated at 375,000ha and a 75% decline is thought to have occurred since 1900.

Many ponds have been lost simply through being filled in or drained, either deliberately, to release land for farming, or inadvertently, by farmers taking too much ground water for their crops

Where they have survived they face pollution from chemicals such as fertilisers washed off fields. Neglect is also a problem, as eventually a healthy pond will silt up and dry up if it is not cleared out occasionally.

Where they are not neglected, ponds are often managed poorly with inappropriate stocking of fish or damaged by accidental introductions of exotic creatures, such as terrapins and foreign crayfish. On top of all this, they are often subject to pressures from fishing and boating.

Knowledge about our ponds is vital if we are to help them. Knowledge of pond and lake distribution and quality is being gathered through a wide range of organisations and projects, and, although the National Pond Survey has representative high-quality ponds in Cornwall, Devon, Dorset and Somerset (c40 sites in total so far), a blanket survey identifying all the 'key' sites is still needed.

Only a minority of the South West lakes, and an even smaller proportion of its ponds, enjoy protection within reserves or under legal designation. Many organisations offer advice on pond and lake construction and management, but funding is limited.