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Collation of evidence of nitrogen impacts on vegetation in relation to UK biodiversity objectives 2011


This report presents the largest analysis of national vegetation data sets in relation to nitrogen (N) deposition carried out to date. The study statistically analysed eight independent national vegetation surveillance datasets using a consistent approach, to identify evidence of N deposition impacts in four habitat types; acidic and calcareous grassland, heathland and bogs.

This new analysis was the largest of its kind, using data from the Vascular Plant Database (1930–1969 and 1987–1999), BSBI Local Change Survey (1987–1988 and 2003–2004), British Bryological Society, British Lichen Society, Plantlife Common Plant Survey, and three country grassland datasets. The project took four widespread habitats – calcareous grasslands, acid grasslands, heathlands, and bogs – and for each, looked for evidence of vegetation change caused by nitrogen deposition, after accounting for other factors that could have an impact.

The study clearly demonstrated significant changes in the abundance of individual species and variables describing habitat structure and function as a result of N deposition. This, together with previous evidence from surveys and experiments, provides clear evidence of species-level impacts of N deposition in all four of the habitats investigated.

Results are presented individually for each of the datasets examined. The discussion section draws the results together examining them for each habitat. Key results are provided in the results section of the report. A complete set of all significant results are presented in the Electronic Appendix.

The analysis presented in this report (No. 447) represents the first part of a large study of nitrogen impacts on vegetation. In a second part of the project, reported in JNCC Report No. 449, the results of this new analysis, together with other sources of independent evidence, are interpreted in respect of implications for “conservation commitments”. A project summary for reports 447 and 449, presenting the key messages and summarising the impacts, accompanies Report No. 449.

Resource type Publication

Topic category Environment

Reference date 2011·03·01

Stevens, C.J., Smart, S.M., Henrys, P., Maskell, L.C., Walker, K.J., Preston, C.D., Crowe, A., Rowe, E., Gowing, D.J. & Emmett, B.A. 2011. Collation of evidence of nitrogen impacts on vegetation in relation to UK biodiversity objectives. JNCC Report, No. 447, JNCC, Peterborough, ISSN 0963-8091.

This project was jointly funded by Defra, the Joint Nature Conservation Committee, Natural England, the Countryside Council for Wales (Natural Resources Wales) and Scottish Natural Heritage.

Responsible organisation
Communications, JNCC publisher

Limitations on public access No limitations

Use constraints Available under the Open Government Licence 3.0

Metadata date 2020·02·04

Metadata point of contact
Communications, JNCC

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