A review and application of the evidence for nitrogen impacts on ecosystem services

Levels of reactive nitrogen (N) in the atmosphere have been elevated globally by man’s activities, with both positive and negative impacts. Since 1990, N emissions across Europe have declined by around 25% due to emissions controls. Ecosystem services provide a framework for valuing N impacts on the environment, and this study provides a synthesis of the evidence supporting impacts of atmospheric N deposition on ecosystem services. In an ex post assessment for the UK, for six services, we then estimate the marginal economic value of the decline in N deposition from 1987-2005. This decline resulted in a net benefit (Equivalent Annual Value) of £65m (£5m to £123m, 95% CI). The decline in N resulted in a cost (loss of value) for provisioning services: timber and livestock production of -£6.2m (-£3.5m to -£9.2m, 95% CI). There was a cost in terms of reduced CO2 sequestration and a benefit in terms of reduced N2O emissions which combined amounted to a cost for greenhouse gas regulation of -£15.7m (-£4.5m to -£30.6m). However, there were benefits for the cultural services of recreational fishing and appreciation of biodiversity, which amounted to £87.7m (£13.1m to £163.0m), outweighing costs to provisioning and regulating services. Knowledge gaps in both the under-pinning science and in the value-transfer evidence still prevent economic valuation of many services, particularly for cultural services, providing only a partial picture of N impacts which may underestimate the benefits of reducing N deposition.