It’s not only rivers

A couple of weeks ago the publication of new research on the global threats to rivers was highlighted. The summary of the paper is here, though to read it in full you will need to ask the authors for a copy unless you can get access to the science journal Nature directly.

It’s worth reading because it’s important; and there’s the added benefit that its written in language that any reasonably intelligent English speaker could understand – which is more that one can say for many Nature papers which depend on the dense and, even to the reasonably well-educated outsider, completely impenetrable technical language of the particular science discipline.

But I wanted to highlight something that the paper doesn’t mention: it uses ‘rivers’ as symbolic of freshwater.

But we know that standing waters – lakes and ponds – make up maybe half the global water area.

Remarkably, little ponds (or at least waterbodies no more than 10 ha in area) make up one-third of that water by area. This is because there are millions and millions of them – and only a relative handful of big lakes.

This is not well-known – and unless people have read the study by Prof. John Downing and his colleagues (here) it will be news to them.

In Britain, perhaps elsewhere too (no-one actually knows), little ponds have more endangered species than rivers, and in several places where we have looked around Europe they actually support more species than rivers altogether – not just more rare things.

Overlooking little ponds because they are small is what John Downing has called ‘a long-standing error of scientific reasoning‘ (he says it in this paper).

That part of the story hasn’t yet made it into Nature.