The importance of farm ponds as wildlife habitats

THE IMPORTANCE OF FARM PONDS AS WILDLIFE HABITATS* Juliet Hawkins Most people love water - whether in lakes, muddy village ponds, small garden ponds or those I most commonly deal with - farm ponds. As a Farm Conservation Adviser for the Suffolk Farming and Wildlife Advisory Group (FWAG) I visit over 100 farms each year and 95% of visits include giving advice on ponds - whether creating new or restoring old ones, Suffolk has more ponds than any other county except Cheshire and, as a result of the farmers' interest, Suffolk FW AG has been able to raise money from sponsors (Bayer, Ciba-Geigy, Monsanto) to investigate some of the more commonly discussed problems. John Digby and Jack Shields have done much of the research work. Leaflets will be printed for the use of advisors, farmers and the general public on pond ecology, the siting and landscaping of ponds, and on problems with algae and ducks on ponds.

The importance of ponds as wildlife habitats depends upon many interlinked factors, such as the original objectives of the pond, its siting, and the subsequent use and management. The primary objectives will influence their value for wildlife. Most ponds we see today are not there to provide 'wildlife habitats', although some new ponds are created with that in mind. The Suffolk Wildlife Trust/FWAG pond at the Suffolk Showground was designed to demonstrate the design features of a pond that are important to wildlife.

Many ponds and lakes were created to enhance the landscape and are often of rather formal design. They tend to have limited value for wildlife, partly due to ruthless 'tidying' management and a clash of objectives with keeping fish or duck. Similarly, one finds this conflict often with small garden ponds.

Although feeding duck with pieces of bread may give delightful amusement for village children, duck in any numbers cause problems of erosion to pond edges, enrichment of the water from their faeces, and disturbance of the water leading to turbid water in which plants do not grow well - and if they do grow they may be pulled up and eaten by the duck. Thus there is very little of interest in terms of other wildlife when there are many duck on a small pond.

However, many ponds, flighting ponds and decoys were designed exclusively for trapping or shooting duck and, when no longer used for this, provide excellent wildlife refuges. Duck decoys are star-shaped ponds with long, finger-shaped extensions to create special catching 'pipes'. Dogs were trained to run up and down beside these 'pipes' to entice the duck to inquisitively swim after them so that they may be trapped.

Fish rearing was of great importance in mediaeval times as a source of protein and specially designed fish ponds were made. Moats, often perhaps built in mediaeval times as much to keep up with the Joneses as for defence, * From a paper delivered at the 'Water Wilderness' conference held at Ipswich School Conference Centre on 27th October, 1990.

Trans. Suffolk Nat. Soc. 28 (1992)

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Suffolk Natural History, Vol. 28

were also used as fish ponds. Today, these steep-sided ponds and moats are often overgorwn, silted, with little aquatic or marginal Vegetation, and support little wildlife. More recently, fishing has become bigger business and farmers, encouraged to diversify, can get grants to dig new ponds for game or coarse fishing. Small farm ponds will support a variety of coarse fish, including carp, roach and rudd, all of which will co-exist with other wildlife to varying degrees. Bottom feeders like carp stir the water, thereby causing turbid conditions unfavourable for plant establishment.

Rearing ornamental fish such as koi-carp can be another profitable diversification venture, even at the garden pond level, but other wildlife will not then be welcome. A heron, beautiful as it is, may spear a fish worth ÂŁ200 with one stab! Rearing crayfish can be another option. The degree to which wildlife will benefit depends upon the stocking density and the management.

I know of one pond which has both crayfish and newts living side by side.

Most ponds near farm buildings were created to water livestock and have little wildlife as they tend to be steep sided (often brick-lined) with one gentle slope to give access to stock and farm carts. They are very vulnerable to pollution from yard washings and slurry. The farm ponds in meadows used to water stock sometimes have followed the excavation of clay lump for building material. A pond heavily used by stock which is stirred and grazed of all Vegetation can often be improved for wildlife by simple management fencing off part of the pond and leaving access at only one point for livestock to drink.

When a new farm pond is being created - be it to stÜre water for irrigation, rear trout or crayfish, or even to enhance the landscape - there are ways in which the farmer can simultaneously encourage wildlife and make it more attractive generally, without extra expence. Many farmers are anxious to do this today. If possible, the new pond should be linked to existing, species-rich habitats which will, for example, provide food for any developing froglets or dragonflies. A gently graded barik profile (say 1 in 4) will ensure that Vegetation becomes established, and an irregulär outline lengthens the edge where semi-aquatic plants grow. An ideal depth is probably 3m, to allow for temperature stability and to allow for exceptionally dry summers and low water levels. It is important to get a balanced, well-established habitat before introducing commercial species.

If a pond is well vegetated with natural food and cover more wildlife will co-exist with other, commercial species such as fish, when they are introduced. The Suffolk FW A G Pond Research Project is providing new design ideas for farm ponds and Suffolk FW A G is more than Willing to pass on their experience of pond management to farmers.

Juliet Hawkins, Suffolk Farming and Wildlife Advisory Group, c.o. MAFF, Government Offices, Southgate Street, Bury St. Edmunds.

Trans. Suffolk Nat. Soc. 28 (1992)