The Impact of Atmospheric Nitrogen Deposition on Grasslands: Species Composition and Biogeochemistry

Atmospheric nitrogen deposition has the potential to alter species composition and species richness in grasslands, but until recently the effects of nitrogen deposition had not been demonstrated at a large scale. Using sixty-eight grasslands along the gradient of ambient atmospheric nitrogen deposition in the UK, this book investigates damage caused by acidification and eutrophication. The results show a clear loss of species richness along this nitrogen deposition gradient. Forbs account for the majority of this decline, showing reductions in both cover and abundance along the nitrogen deposition gradient. Using canonical correspondence analysis, several individual species are identified as being positively and negatively associated with nitrogen deposition. Changes in soil and plant tissue chemistry are also reported including declines in soil pH, mobilisation of aluminium, arsenic and lead in the soil, and increased soil ammonia concentration along the nitrogen deposition gradient. This analysis should help shed some light on the actual impact of nitrogen deposition to semi- natural grasslands in the UK.