The urban population is growing every year. This affects urban biodiversity.
Especially in populated areas like the city, biodiversity is important for providing ecosystem services such as pest regulation - think of the oak processionary caterpillar.
Ecologist Juan Antonio Hernández-Agüero, together with master students, investigated 40 summer oaks in Amsterdam. In the trees, they placed artificial caterpillars made of modelling clay.
According to the researchers, noise is the main factor influencing bird behaviour. Birds avoid noisy areas. As a result, there is less natural pest control near roads or railway lines. 'That's a problem, because car and train traffic cannot just be stopped,' says Hernández-Agüero. However, the researchers do see a role for noise barriers. 'These have been used for a long time and we show that they are more necessary than ever.'
Impermeable surfaces, artificial light at night, high population density and local temperature rises (due to heaters) also influence bird behaviour. These human influences increase bird activity during cold and dark periods, but actually have a negative effect during warmer and lighter periods