Nitrogen also affects soil invertebrates and insects

Higher levels of nitrogen in the environment (coming from fertilisers and livestock, for example) not only affect plants but also soil invertebrates and insects. The diversity of roundworms declines in areas with high input of nitrogen, and numbers of some arthropods drop. However, other species of arthropods benefit from the extra nitrogen. What is more, climate change may amplify the negative effects of nitrogen. This is the conclusion reached by a group of researchers from Radboud University, including Juan Gallego-Zamorano and Aafke Schipper, who performed a meta-analysis of 126 studies worldwide. Gallego-Zamorano: 'We know that many species of wild plants do not do well if the amount of nitrogen in the soil is artificially increased. But much less is known about the effects of nitrogen on the animals that live in or on this soil.' To investigate that, he and his colleagues analysed the results of 126 studies worldwide that counted the number of species and individuals of roundworms and arthropods (such as butterflies, locusts or spiders) occurring in experimental plots to which nitrogen had been added.