Many people have a mental picture of the ‘perfect pond’ – probably a bulrush-fringed pond on a village green, with a few ducks lazily sculling on the surface.
However, many of our most threatened freshwater creatures can’t live in these types of ponds. Tadpole Shrimps and Fairy Shrimps need transient ephemeral ponds to live in, making the most of the brief window when they fill with water to complete their life cycle. Some, like Great Crested Newts, can’t tolerate fish, which eat their young and many others, including types of caddis, alderfly and dragonfly need clean water – the sort you can only find in woodlands or flower-rich meadows with a completely unpolluted catchment.
One of our favourite plants is the Tassel Stonewort. It looks like a pondweed – but in fact it’s a stonewort – a much more ancient living link between algae and the herbs, reeds and rushes that colonise most of our ponds. It’s a species that likes bare muddy places at the edge of shallow ponds – the sort where animals might drink, and in doing so trample (or poach) the edges, proving the perfect environment for it.
Tassel stonewort is also a bit of an adventurer – it’s strongly associated with pools on old drove roads and green lanes and depends on animals’ hooves to get around – hitching a ride to move to new homes.
Sadly, although stoneworts like these have thrived on earth for over 350 million years, in the 21st century, the widespread field drainage, water pollution and increasingly intensive livestock production practices, make their pond and pool homes harder to find – and, along with them, the Tassel Stonewort is gradually disappearing from our landscape.
Pond Conservation is working hard to redress this situation by creating new, clean-water ponds and pools in areas that can be poached by livestock, to provide ideal homes for this very special species. Plant spores can then be introduced to these special new ponds, to ensure that another one of our rare freshwater species is brought back from the brink.
We are grateful to the John Spedan Lewis Foundation for enabling us to carry out this work in Oxfordshire – one of the few places in Britain where the Tassel Stonewort is still known to exist.