Dragonflies and wildlife-friendly river banks in towns and cities

An experiment in Gouda has shown that dragonflies benefiting from the creation of wildlife-friendly river banks.

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Dragonflies are found near water and are very dependent on the water quality, the way the water and its edges are managed, and how these water edges are landscaped. Gouda municipal council has created wildlife-friendly canal and river banks in the city. These banks are gently sloping, have little bays, and are managed in a certain way.

In 2000 these banks were compared with conventional banks and it was found that they harboured more than three times as many individual dragonflies (of all species pooled: see the bar chart on the left-hand side). Furthermore, the average number of species was higher on the wildlife-friendly banks (see the bar diagram on the right-hand side). Certain species were found only on the wildlife-friendly banks. They included Aeshna viridis and the Norfolk hawker, both of which are on the Red List of dragonflies.