Wednesday, 7 July 2010

Signs of the times: Summer #5

More comparisons between the British countryside of today and that from 1959-1961 in the paintings of Charles Tunnicliffe in the Ladybird "What to look for..." series of books.

"Every peasant is proud of the pond in his village because from it he measures the sea."
Russian proverb

(Copyright: Ladybird Books)

Summer Picture 5

You can see from this picture that we are down in a pond – a range of ferocious predatory invertebrates on show, which bears some careful description of what is what – a great diving beetle (Latin name: Dytiscus marginalis ) adult on the centre right (with a young frog in its mandibles), and its larva at the top centre, a great silver water beetle (Hydrophilus piceus) in the top left corner, a formidable dragonfly larva in the bottom left corner, which has shot out its extendable “face mask” to grab a small worm or larva. The water scorpion (Nepa), the brown “bug” in the bottom right with the caddis larva in its jaws, is another larger pond predator that does occur in Scotland. The “water stick insect”, which should be obvious in the bottom left of the picture doesn’t occur in Scottish ponds and I don’t know anything about them. But I will find out (just not right now).

The smaller swimming bug in the top right really is a bug, the great water boatman (Notonecta) being a hemipteran, the water bug family. Although smaller than the water beetles and their larva, and the dragonfly larva (probably all the top predators in ponds, particularly those without fish), the greater water boatman is also a fierce predator.

There are also two snails in the picture, in fact the two largest species normally found in British ponds, the ramshorn snail (the lower of the two in the picture, Planorbis) and the great pondsnail (Lymnaea stagnalis) – I have both species in my garden pond, from which the ramshorn snails are regularly hoicked out by the local song thrushes and bashed to pieces on the pond’s stepping stones, to be eaten! Bottom right are a couple of caddis fly larvae, well-known as a group for their making of protective cases from a rage of materials, in this case plant fragments (but some species alternatively use gravel, tiny snail shells and other materials). It should be noted, however, that not all caddis fly larvae will make cases – there are also many so-called caseless caddis species. Obvious from the name, these are flies with an adult, out-of-water life stage, but the larval stages are spent in fresh water.

The inclusion in the picture of the great silver water beetle tells me that this pond is likely to be in south-west Britain, probably in the Somerset Levels (but maybe also in the Pevensey levels and East Anglia), as this is where this species is now largely found (it was more widespread in the past, estimated to have been living in fewer than fifteen 10km squares in Britain since 1970. It has suffered a 25-49% decline in the last 25 years in GB, probably as a result of nutrient enrichment of the small standing water bodies, ponds, ditches etc where it lives, as a result of agricultural run-off).

So far, so pond-like, and definitely not a picture from a pond in Scotland. Some Scottish pond information I found recently, from the Countryside Survey report of 2007, indicates that, between 1998 and 2007, the number of ponds in Scotland increased by 6%, so maybe the long-term decline in pond numbers is being reversed at long last. This might be the result of ponds created through funding for agri-environment measures, to improve the benefits of agriculture for wildlife, and the increase in ponds created to hold and treat run-off from roads (so-called sustainable urban drainage ponds).


  1. Interesting.........

    Urban drainage ponds???.........never thought of that before.

    Now you mention it though.....

    welcome back.......Al.

  2. Thanks!
    Oh, I can bore for Scotland on urban drainage ponds - definite SNB blog material - my organisation has led on the introduction of these to the UK and they are now a statutory requirement for all major developments, new roads, anything other than very small car parks, etc. But lots of them are also good pond habitats - more to follow in due course...


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