It’s easy to assume that as the weather gets colder life shuts down under water. The bulrushes are dying back now, and it won’t be long before we have our first frosts.
But dipping the pond today shows just how much is going on over winter.
I can see swarms of tiny, recently hatched Smooth Ram’s-horn snails (Gyraulus laevis – pictures here: dead shells show best the distinctive glossy appearance) – there seem to be hundreds amongst the grasses at the pond edge. With them are full grown Whirlpool Ram’s-horns. The Smooth Ram’s-horn is the most unusual animal in the pond at present: it’s a specialist of new ponds and only patchily distributed across the country.
Lurking in the dense cover of trailing ivy, fallen leaves and submerged mosses at the back of the pond are mating Spotted Backswimmers (Notonecta maculate), Broad-bodied Chaser dragonfly larvae (Libellula depressa) and quite a number of full grown Large Red Damselfly larvae.
Numbers of Pond Olive mayflies are rising now too – there are many hundreds in the pond, including tiny specimens that hatched in the autumn and will grow over the winter to emerge in the spring.
Water beetles are usually harder to find in autumn and winter when many species migrate away from smaller ponds but I did find a Common Black Scavenger Beetle (Hydrobius fuscipes – there’s a rather beautiful picture of it here on this Russian website showing the distinctive rows of fine dots on the wing cases), a Helochares lividus – another edge loving scavenger beetle found amongst the trailing grasses – and the larvae of the Common Black Water Beetle (Agabus bipustulatus) and of small diving beetles in the genus Hydroporus (these are not really identifiable in the field).
There are still pond skaters but no sign of any lesser water boatmen at present.
And in some ways most surprising of all: a couple of frog tadpoles quietly sheltering amongst the marginal grasses. It’ll be interesting to see whether they make it through the winter.
