How do climate warming and plant species richness affect water use in experimental grasslands?
How do climate warming and plant species richness affect water use in experimental grasslands?
复制标题
DOI：
10.1007/s11104-006-9112-5
复制
发表时间：
2006-10-01
期刊：
影响因子：
4.9
通讯作者：
Ceulemans, R.
中科院分区：
文献类型：
--
作者：
De Boeck, H. J.;Lemmens, C. M. H. M.;Ceulemans, R.
气候变暖和植物物种丰富度的丧失是许多实验的主题，但关于它们联合影响的研究还很缺乏。在这里，我们研究了气候变暖和物种丰富度丧失如何影响草原的水分利用，同时确定了这些全球变化之间的相互作用。实验生态系统包含来自三个功能组的一个、三个或九个草地物种，在比利时Wilrijk的12个阳光充足的气候控制室(2.25m(2)地面面积)中种植。其中一半的房间暴露在环境空气温度下(未加热)，而另一半则升温3摄氏度(加热)。在加热和不加热的社区中加入等量的水，因此如果蒸散量(ET)较高，变暖将意味着土壤更加干燥。在最初的ET值对气候变暖作出响应后，气孔调节和较低的地上生产力导致ET值与非采暖群落中记录的ET值相当。由于生物量的减少，水分利用效率(WUE)也因气候变暖而降低。更高的互补性和混合栽培中节水物种的竞争成功，导致多物种群落中的WUE比单一养殖群落中的WUE增加，而不考虑引起的变暖。然而，由于个别物种的WUE受到较高温度的不同影响，由于竞争力的变化，混合物中的组成似乎可能在气候变化下发生变化。总之，虽然增加的互补性和对节水品种的选择确保了混合栽培比单一栽培更有效地利用水，但全球变暖可能会降低这种WUE，这可能在物种丰富的群落中最为明显。
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 m(2) ground area) in Wilrijk, Belgium. Half of these chambers were exposed to ambient air temperatures (unheated), while the other half were warmed by 3 degrees 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.