Why are ponds important?

Ponds are important hotspots for biodiversity.  Collectively, they support more species, and more scarce species, than any other freshwater habitat (Céréghino et al. 2008).  They are also more abundant than almost any other freshwater habitat, and are found in virtually all environments.  Despite this, very little research has been conducted on ponds and their ecological value, and most conservation approaches are largely uninformed by science.

Comparative species richness of macro-invertebrates and aquatic plants, in four different aquatic environments.  From paper by Williams et al. (2003), who found good quality ponds to be about as rich in species as good quality sections of river.
Comparative species richness of macro-invertebrates and aquatic plants, in four different aquatic environments. From paper by Williams et al. (2003), who found good quality ponds to be about as rich in species as good quality sections of river.

 

Because individual ponds vary significantly in their species compositions, overall they often contribute more to regional biodiversity than rivers or other habitats.  On top of this, ponds are relatively small and easy to manage environments, so that we can improve or restore a great number of ponds for the same effort / money it would cost to improve just one stretch of river.

As well as aquatic species, ponds are also wonderful for our terrestrial wildlife.  They provide drinking water during dry weather, a supply of insect and plant-based food, and shelter among the emergent and surrounding plants and trees.  This is especially important in environments which are otherwise lacking in places for wildlife; a rich tapestry of ponds across an intensive agricultural landscape provides a much needed refuge for birds, mammals, amphibians (which will cross even large fields to get to a pond), reptiles, and flying insects.

For these reasons, farmland ponds are especially important in the UK and across much of Europe, where a substantial proportion of land is given over to food production.  Despite their importance, little attention has been paid to protecting farmland ponds; all too often these habitats are written-off as unsuitable for wildlife, being seen as too small, too nutrient rich, and too polluted to be of real conservation value.

This is a huge shame, as not only are farmland ponds vastly more numerous than ‘pristine’ ponds, they can also be just as diverse and valuable for wildlife (See A farmland success story).

Aerial photo of marl pit ponds in north Norfolk - notice the occasional "ghost pond" - dry depressions in the fields
Aerial photo of marl pit ponds in north Norfolk – notice the occasional “ghost pond” – dry depressions in the fields.

 

Apart from the benefits farmland ponds have for wildlife, there are other strong reasons for protecting them.

Most farm ponds exist at natural low points in the fields, being fed by water seeping off the farmland.  They act as mini-reservoirs, helping drain the fields during heavy rain, while leaching water slowly into dry ground in times of drought.  Through collecting and slowing the flow of water off the fields, ponds trap and recycle nutrients, reducing the quantities of nitrates and phosphates entering the river system.

Almost all ponds are man-made, and steeped in local history.  Every region has a different ‘type’ of pond, dug in a different way or for a different purpose (if you are interested in the history of ponds, or in fact the history of the countryside more generally, Oliver Rackham’s History of the Countryside is a fantastic read).

Ponds tell the story of the people who used them every day; for soaking cart wheels, watering horses, driving mills, extracting clay for bricks or fishing for their supper.  And their appeal is not just historic – children (and some adults who haven’t grown up), will always be fascinated by water and ponds, and I think many of us will remember chasing frogs or fish in the local duck pond.

Me at the age of 3 starting my career in aquatic ecology.
Me at the age of 3 starting my career in aquatic ecology.

 

Improving our understanding and management of farmland ponds can help us to provide excellent wildlife havens, right in the middle of the landscapes where they are most needed.  The beneficial effects of having numerous, good quality farmland ponds would be far reaching, improving water quality, reducing water and soil loss from fields, and providing generations to come with places to explore the wonder of nature.

 

References

Céréghino R, Biggs J, Oertli B & Declerck S (2008)  The Ecology of European ponds: defining the characteristics of a neglected freshwater habitat  Hydrobiologia 597: 1-6.

Williams P, Whitfield M, Biggs J, Bray S, Fox G, Nicolet P & Sear D (2003)  Comparative biodiversity of rivers, streams, ditches and ponds in an agricultural landscape in Southern England.  Biological Conservation  115: 329-341.

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