Does background nitrogen deposition affect the response of boreal vegetation to fertilization?
Oecologia
; 173(2): 615-24, 2013 Oct.
Article
em En
| MEDLINE
| ID: mdl-23504175
ABSTRACT
Forest floor vegetation is an important component of forest biodiversity, and numerous studies have shown that N input alters the vegetation. In some cases, however, the effects of experimental N addition have been small or absent. Two alternative hypotheses have been suggested (a) competition from the tree layer confounds the response to N, or (b) N response in areas with high background deposition is limited by N saturation. Neither of these hypotheses has so far been explicitly tested. Here, we compile data on forest floor vegetation from N addition experiments, in which the forest had been clear-cut, along an N deposition gradient ranging from 4 to 16 kg ha(-1) year(-1) in Sweden. We analyzed the effects of N addition and its interaction with N deposition on common species and thereby tested the second hypothesis in an environment without the confounding effects of the tree layer. The results show that the effects of the experimental N addition are significantly influenced by background N deposition the N addition effects are smaller in areas with high N deposition than in areas with low N deposition, despite the fact that the highest N deposition in this study can be considered moderate from an international perspective. The results are important when assessing the reliability of results from N addition experiments on forest floor vegetation in areas with moderate to high background N deposition. We conclude that the interacting effects of N addition and N deposition need to be included when assessing long-term N sensitivity of plant communities.
Texto completo:
1
Base de dados:
MEDLINE
Assunto principal:
Ecossistema
/
Fenômenos Fisiológicos Vegetais
/
Nitrogênio
País/Região como assunto:
Europa
Idioma:
En
Ano de publicação:
2013
Tipo de documento:
Article