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Warming and drought alter C and N concentration, allocation and accumulation in a Mediterranean shrubland
Sardans i Galobart, Jordi (Centre de Recerca Ecològica i Aplicacions Forestals)
Peñuelas, Josep (Universitat Autònoma de Barcelona. Departament de Biologia Animal, de Biologia Vegetal i d'Ecologia)

Data: 2008
Resum: We investigated the effects of warming and drought on C and N concentrations, nitrogen use efficiency (NUE), and C and N accumulation in different ecosystem compartments. We conducted a 6-year (1999–2005) field experiment to simulate the climate conditions projected by IPCC models for the coming decades in a Mediterranean shrubland. We studied the two dominant species, Globularia alypum and Erica multiflora, and an N-fixing species, Dorycnium pentaphyllum, also abundant in this shrubland. Warming (1 °C) decreased N leaf concentrations by 25% and increased N stem concentrations by 40% in G. alypum. Although warming changed the available ammonium in soil in some seasons, it did not increase total soil N contents. Drought (19% average reduction in soil moisture) decreased leaf N concentrations in the two dominant shrub species, E. multiflora and G. alypum by 16% and 19%, respectively, and increased stem N concentrations by 56% and 40%, respectively. Neither warming nor drought changed the leaf N concentrations in the N-fixing species D. pentaphyllum, although warming increased stem N concentration by 9%. In G. alypum, the increase of stem N concentrations contributed to the observed increase of N accumulation in stem biomass in drought treatments with respect to control plots (8 kg N ha−1). Neither warming nor drought changed NUE in the period 1999–2005. Warming increased soil organic C relative to drought. The effects of warming and drought on C and N concentrations, on N accumulation and on leaf/stem N distribution were not the result of dilution or concentration effects produced by changes in biomass accumulation. Other factors such as the changes in soil N availability, photosynthetic capacity, and plant internal C and N remobilization must be involved. These changes which differed depending on the species and the plant tissue show that the climate change projected for the coming decades will have significant effects on the C and N cycle and stoichiometry, with probable implications for ecosystem structure and function, such as changes in plant–herbivore relationships, decomposition rates or community species composition.
Drets: Tots els drets reservats
Llengua: Anglès.
Document: article ; recerca ; publishedVersion
Matèria: C/N ; Climate change ; Dorycnium pentaphyllum ; Drought ; Erica multiflora ; Globularia alypum ; Mediterranean shrubland ; N ; NUE ; Warming ; Canvi climàtic ; Sequera ; Matoll mediterrani ; Escalfament ; Cambio climático ; Sequía ; Matorral mediterráneo ; Calentamiento
Publicat a: Global Change Biology, Vol. 14, Núm. 10 (Octubre 2008) , p. 2304-2316, ISSN 1365-2486

13 p, 372.3 KB

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Documents de recerca > Documents dels grups de recerca de la UAB > Centres i grups de recerca (producció científica) > Ciències > CREAF (Centre de Recerca Ecològica i d'Aplicacions Forestals)
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