Saturday morning me and Mika got our welly boots on and went to a small workshop to look at the biodiversity in Francolí river, just outside of Tarragona. Apparently it is the most polluted river in Europe, so in terms of biodiversity is one of the lowest as low biodiversity corresponds with high pollution in lakes, rivers and ponds. Only the most robust species are able to survive.
But there were still some things to be found, like the American crayfish (not the native Iberian crayfish), dragonfly larvae, damselfly larvae, mayfly nymphs, a frog and a tadpole, and an air breathing aquatic beetle that doesn’t look aquatic, plus various other little creatures. I don’t know how many times I’ve done surveys in water habitats like this, taking a net and tray and seeing what there is, but it’s always very interesting. The main difference was that it wasn’t in English but Catalan, which surprisingly I could catch some of.
The American crayfish is causing problems with the native Iberian Crayfish, since it is more competitive and more immune to a fungal disease that is killing of the Iberian crayfish. We’re lucky enough to have a small colony of Iberian crayfish in a stream on the land, and I hope it remains like that for a long time to come.