Biomass production in experimental grasslands of different species richness during three years of climate warming
Biomass production in experimental grasslands of different species richness during three years of climate warming
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DOI：
10.5194/bg-5-585-2008
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发表时间：
2008-01-01
期刊：
影响因子：
4.9
通讯作者：
Nijs, I.
中科院分区：
文献类型：
--
作者：
De Boeck, H. J.;Lemmens, C. M. H. M.;Nijs, I.
在这里，我们报告了气候变暖和物种丰富度对实验草原群落生物量生产的单一和综合影响。对未来气候变暖的预测刺激了对陆地生态系统对这一全球变化的响应的研究。实验同样强调了物种数量对于生态系统功能的重要性。然而，人们对变暖与物种丰富度之间的相互作用知之甚少。在三年的时间里，我们在比利时威尔赖克的 12 个阳光明媚、气候可控的房间里种植了包含一种、三种或九种草原物种的实验植物群落。这些室的一半暴露于环境空气温度（未加热），而另一半则加热 3 摄氏度（加热）。向加热和未加热的社区添加等量的水，因此如果蒸散量较高，变暖将意味着土壤干燥。由于夏季炎热和干旱胁迫加剧的负面影响，地上（-29％）和地下（-25％）的生物质产量均因变暖而减少。互补效应（可能主要是通过增加地上空间互补性和豆科植物的促进效应）导致多物种群落中较高的芽和根生物量，无论是否引起变暖。令人惊讶的是，变暖对 9 个物种群落的生产力的抑制最为严重，这可能是由于在高非生物胁迫条件下种间激烈的资源竞争造成的负面影响。我们的研究结果表明，变暖和相关的土壤干燥可能会减少许多温带草原的初级生产力，并且这种情况不一定会通过维持或增加物种丰富度的努力来缓解。
Here we report on the single and combined impacts of climate warming and species richness on the biomass production in experimental grassland communities. Projections of a future warmer climate have stimulated studies on the response of terrestrial ecosystems to this global change. Experiments have likewise addressed the importance of species numbers for ecosystem functioning. There is, however, little knowledge on the interplay between warming and species richness. During three years, we grew experimental plant communities containing one, three or nine grassland species in 12 sunlit, climate-controlled chambers 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 was higher. Biomass production was decreased due to warming, both aboveground (-29%) and belowground (-25%), as negative impacts of increased heat and drought stress in summer prevailed. Complementarity effects, likely mostly through both increased aboveground spatial complementarity and facilitative effects of legumes, led to higher shoot and root biomass in multi-species communities, regardless of the induced warming. Surprisingly, warming suppressed productivity the most in 9-species communities, which may be attributed to negative impacts of intense interspecific competition for resources under conditions of high abiotic stress. Our results suggest that warming and the associated soil drying could reduce primary production in many temperate grasslands, and that this will not necessarily be mitigated by efforts to maintain or increase species richness.