The Sussex Weald: the caddisfly on the streambed

St. Leonard’s Forest, West Sussex, December 2020

The cold has come to the woods, and with it, the silence of birds. It’s not all quiet. Rain has fallen overnight and there is a gushing to the hill as it wends its way through the woodland. Looking at the water I see the bare sandstone. The water, over a very long time, has cut through the soils and softer substrates. Walking here over several years I have wondered why the sandier heathlands rest high up and the ancient woodlands of oak, beech, hazel and holly grow only really in the clay gulleys. It’s here, the answer.  The stream has cut through the sand and washed the gravel away to reach the sandstone.

I follow the twisting stream up hill, jumping from bank to bank, where vegetation blocks progress. In a slowed stretch something small and black is moving against the flow on the clay streambed. It’s an invertebrate, what I think is a caddisfly with a pack of debris on its back. It looks to be trying to grab at a small stone or piece of material on the streambed. It could be ready to attach itself to the stone and move to its next stage, the pupa, before becoming an adult insect for a month next year.

Ferns spool out from the freshly leaf-laden banks and the trees are drenched in moss. It dawns on me: this is south-east England’s rainforest.

The Sussex Weald

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