How do climate warming and plant species richness affect water use in experimental grasslands

• Published in: Plant and soil Vol. 288; no. 1-2; pp. 249 - 261
• Main Authors: Boeck, H. J. De, Lemmens, C. M. H. M, Bossuyt, H, Malchair, S, Carnol, M, Merckx, R, Nijs, I, Ceulemans, R
• Format: Journal Article Web Resource
• Language: English
• Published: Dordrecht Dordrecht : Kluwer Academic Publishers 01.10.2006; Springer; Springer Nature B.V
• Subjects: Agronomy. Soil science and plant productions; Air temperature; Ambient temperature; Animal, plant and microbial ecology; Biological and medical sciences; Biologie végétale (sciences végétales, sylviculture, mycologie...); Biomass; Climate change; Drought; Environmental sciences & ecology; Evapotranspiration; Flowers & plants; Fundamental and applied biological sciences. Psychology; Global warming; Grassland soils; grassland species; Grasslands; High temperature; Life sciences; Monoculture; Phytobiology (plant sciences, forestry, mycology...); Plant species; Plants; Sciences de l’environnement & écologie; Sciences du vivant; Soil heating; Soil water; Soil water content; soil-plant-atmosphere interactions; Species; species diversity; Species richness; Water use; Water use efficiency; Belgium; Soil plant relation; Evapotranspiration, Global warming, Grassland species, Species richness; Water use efficiency
• ISSN: 0032-079X; 1573-5036; 1573-5036
• DOI: 10.1007/s11104-006-9112-5

Climate warming and plant species richness loss have been the subject of numerous experiments, but studies on their combined impact are lacking. Here we studied how both warming and species richness loss affect water use in grasslands, while identifying interactions between these global changes. Experimental ecosystems containing one, three or nine grassland species from three functional groups were grown in 12 sunlit, climate-controlled chambers (2.25 m² ground area) in Wilrijk, Belgium. Half of these chambers were exposed to ambient air temperatures (unheated), while the other half were warmed by 3°C (heated). Equal amounts of water were added to heated and unheated communities, so that warming would imply drier soils if evapotranspiration (ET) was higher. After an initial ET increase in response to warming, stomatal regulation and lower above-ground productivity resulted in ET values comparable with those recorded in the unheated communities. As a result of the decreased biomass production, water use efficiency (WUE) was reduced by warming. Higher complementarity and the improved competitive success of water-efficient species in mixtures led to an increased WUE in multi-species communities as compared to monocultures, regardless of the induced warming. However, since the WUE of individual species was affected in different ways by higher temperatures, compositional changes in mixtures seem likely under climatic change due to shifts in competitiveness. In conclusion, while increased complementarity and selection of water-efficient species ensured more efficient water use in mixtures than monocultures, global warming will likely decrease this WUE, and this may be most pronounced in species-rich communities.