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InFocus

Importance of ponds in protecting freshwater biodiversity

A Veterinary Practice correspondent discusses the value of ponds and bemoans their decline.

I HAVE long been a fan of creating ponds whenever the opportunity presents because of the rich diversity of habitat, and as a result the wildlife that they support.

A pond, particularly when centred in the middle of intensive farmland, can be truly like an oasis in the desert. Animals and birds flock to it for protection and sustenance and provide all manner of wildlife watching and studying opportunities.

Sadly, a report published at the beginning of the month by the Centre for Ecology and Hydrology in conjunction with the charity Pond Conservation, shows that 80% of the ponds in England and Wales are in “poor” or “very poor” condition.

Pond quality in Scotland is considerably better but the report shows that even here the quality of lowland ponds has deteriorated since 1996. Which is a huge shame considering that recent research has shown that ponds are even more important for the protection of freshwater biodiversity than was previously thought.

In fact, ponds support a greater number of both endangered and common species of plants and animals than either rivers or lakes. And since there are around half-a-million manmade and natural ponds in Britain (not including garden ponds), they are a really important ecological resource.

So what is causing the damage? Well I’m afraid it’s back to “farmer bashing” again because it’s largely the fault of run-off from intensively cropped farmland. This run-off raises the nutrient level in the pond causing it to become overgrown and stagnant. Other causes are pollution from towns, industrial waste and the run-off from roads.

Although the figure of half-a-million ponds nationwide seems impressive, it seems likely that this is only half the number there were at the start of the 20th century. Fortunately, new ponds are now being created (estimated at about 7,000 per year) and it is remarkable how quickly these become established as rich wildlife habitats with even fish arriving in them, seemingly from nowhere. Less fortunately, many of these new ponds will deteriorate over the coming years as they accumulate polluted sediments from the surrounding farmland.

Reliant on quality

Amphibians like frogs and newts are especially reliant on good quality ponds and frogspawn will be appearing all over the country by the time you read this.

We dug a pond at the bottom of one of our fields about eight years ago and it is amazing how the number of “clumps” of frogspawn has increased; from about seven in the first spring to over 100 last year.

I look forward to carrying out another count in the next few weeks. Certainly, the heron that regularly visits will be dining on frogs in the not too distant future.

Of just as much interest to me as the frogspawn is the sudden appearance of the leaves of the marsh marigolds or king cups that surround the pond. These appear like magic and within a few more weeks come the bright yellow flowers that are, for me, one of the sure signs that spring really is on the way.

The intensity of yellow is quite like no other and I’ve even transplanted one or two of them into the garden to give some early season colour and cheer.

One mistake I did make was to plant a few giant reedmace or bullrushes round the edge early on in the pond’s establishment. I hadn’t realised quite how robust and invasive these are and already they have taken over about 30% of the pond area. They are very useful for providing cover but unless I take some action to curtail them they will have turned the pond into an area of marsh within just a few more years.

I am contemplating my options as I write and suspect that I will have to fall back on the strategic use of glyphosate which is apparently very non-toxic to pond life. It’s either that or a lot of hard labour and I’m not convinced that I’ve the time or the inclination for that any more.

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