European semiarid Mediterranean ecosystems are sensitive to nitrogen deposition:impacts on plant communities and root phosphatase activity

Ochoa-Hueso, Raul and Stevens, Carly J. (2015) European semiarid Mediterranean ecosystems are sensitive to nitrogen deposition:impacts on plant communities and root phosphatase activity. Water, Air, and Soil Pollution, 226 (2). ISSN 0049-6979

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Abstract

Nitrogen (N) deposition is predicted to impact on the structure and functioning of Mediterranean ecosystems. In this study, we measured plant species composition, production and root phosphatase activity in a field experiment in which N (0, 10, 20 and 50 kg N ha(-1) year(-1)) was added since October 2007 to a semiarid shrubland in central Spain. The characteristically dominant annual forb element responded negatively to N after similar to 2.5 and similar to 3.5 years. In contrast, the nitrophilous element (mainly crucifers) increased with N after similar to 2.5 and similar to 5.5 years, a response controlled by between-year variations in rainfall and the heterogeneous distribution of P availability. We also described a hierarchy of factors driving the structure and composition of the plant community: soil fertility was the most important driver, whereas calcareousness/acidity of soils and shrub cover played a secondary role; finally, N deposition contributed to explain a smaller fraction of the total variance, and its effects were predominantly negative, which was attributed to ammonium toxicity. Root phosphatase activity of three species was not responsive to N after similar to 2.5 years but there was a negative relationship with soil P in two of them. We conclude that increased N deposition in semiarid Mediterranean ecosystems of Europe can contribute to cause a shift in plant communities associated with an increase in the nitrophilous element and with a decline in abundance of various forb species adapted to the local conditions.

Item Type:
Journal Article
Journal or Publication Title:
Water, Air, and Soil Pollution
Uncontrolled Keywords:
/dk/atira/pure/subjectarea/asjc/2300/2305
Subjects:
ID Code:
73668
Deposited By:
Deposited On:
18 Jun 2015 05:39
Refereed?:
Yes
Published?:
Published
Last Modified:
28 Apr 2020 03:13