Phenology and plant functional type dominance drive CO 2 exchange in seminatural grasslands in the Pyrenees
Ibañez Raffaele, Maria de las Mercedes (Universitat de Lleida. Departament d'Hortofructicultura, Botànica i Jardineria)
Altimir, Nuria (Centre de Ciència i Tecnologia Forestal de Catalunya (CTFC))
Ribas Artola, Àngela (Centre de Recerca Ecològica i d'Aplicacions Forestals)
Eugster, Werner (ETH Zürich. Institut für Agrarwissenschaften)
Sebastià, Ma.T. (Universitat de Lleida. Escola Tècnica Superior d'Enginyeria Agrària)

Date:	2020
Abstract:	Understanding the mechanisms underlying net ecosystem CO2 exchange (NEE) in mountain grasslands is important to quantify their relevance in the global carbon budget. However, complex interactions between environmental variables and vegetation on NEE remain unclear; and there is a lack of empirical data, especially from the high elevations and the Mediterranean region. A chamber-based survey of CO2 exchange measurements was carried out in two climatically contrasted grasslands (montane v. subalpine) of the Pyrenees; assessing the relative contribution of phenology and environmental variables on CO2 exchange at the seasonal scale, and the influence of plant functional type dominance (grasses, forbs and legumes) on the NEE light response. Results show that phenology plays a crucial role as a CO2 exchange driver, suggesting a differential behaviour of the vegetation community depending on the environment. The subalpine grassland had a more delayed phenology compared to the montane, being more temperature than water constrained. However, temperature increased net CO2 uptake at a higher rate in the subalpine than in the montane grassland. During the peak biomass, productivity (+74%) and net CO2 uptake (NEE +48%) were higher in the subalpine grassland than in the montane grassland. The delayed phenology at the subalpine grassland reduced vegetation's sensitivity to summer dryness, and CO2 exchange fluxes were less constrained by low soil water content. The NEE light response suggested that legume dominated plots had higher net CO2 uptake per unit of biomass than grasses. Detailed information on phenology and vegetation composition is essential to understand elevation and climatic differences in CO2 exchange.
Grants:	European Commission 275855 Ministerio de Economía y Competitividad BES-2014-069243 Ministerio de Economía y Competitividad CGL2013-49142-C21-R
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Language:	Anglès
Document:	Article ; recerca ; Versió acceptada per publicar
Subject:	Grasslands ; Legumes ; Light response ; Subalpine ; Net ecosystem exchange
Published in:	The Journal of Agricultural Science, Vol. 158, issue 1-2 (March 2020) , p. 3-14, ISSN 2156-8561

DOI: 10.1017/S0021859620000179

Postprint 43 p, 700.6 KB

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Research literature > UAB research groups literature > Research Centres and Groups (research output) > Experimental sciences > CREAF (Centre de Recerca Ecològica i d'Aplicacions Forestals)
Articles > Research articles
Articles > Published articles