Modelled effects of precipitation on ecosystem carbon and water dynamics in different climatic zones
Modelled effects of precipitation on ecosystem carbon and water dynamics in different climatic zones
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DOI：
10.1111/j.1365-2486.2008.01651.x
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发表时间：
2008-10-01
影响因子：
11.6
通讯作者：
Sowerby, Alwyn
中科院分区：
文献类型：
--
作者：
Gerten, Dieter;Luo, Yiqi;Sowerby, Alwyn
全球气候的持续变化使世界生态系统不仅面临二氧化碳浓度和温度上升的风险，而且还面临降水(P)制度的变化。利用4个成熟的基于过程的生态系统模型(LPJ、DayCent、Orchidee、TECO)，探讨了潜在磷变化对不同水文气候带不同植被类型的7个陆地生态系统水分限制和净初级生产力(NPP)的影响。我们发现，NPP对P变化的响应不仅在不同地点之间不同，而且在给定地点的一年内也不同。NPP变化的大小基本上由生态系统水分限制程度决定，这里使用大气蒸腾需求与土壤水分供应的比率来量化生态系统水分限制程度。与中等湿润或干燥的地点/时期相比，潮湿的地点和/或时期对P的任何变化的反应最小。我们还发现，NPP对磷量翻倍或减半以及磷发生的季节性变化的反应比对年内不变的磷的频率和强度的变化的反应更强烈。这些发现在四个模型中都是非常稳健的，特别是在变化方向方面，并且与早期的P操纵实验和模拟结果基本一致。总体而言，这项研究强调了磷作为生态系统变化驱动因素的广泛重要性，尽管特定地点的最终反应将取决于磷变化的详细性质和季节性时间。
The ongoing changes in the global climate expose the world's ecosystems not only to increasing CO2 concentrations and temperatures but also to altered precipitation (P) regimes. Using four well-established process-based ecosystem models (LPJ, DayCent, ORCHIDEE, TECO), we explored effects of potential P changes on water limitation and net primary production (NPP) in seven terrestrial ecosystems with distinctive vegetation types in different hydroclimatic zones. We found that NPP responses to P changes differed not only among sites but also within a year at a given site. The magnitudes of NPP change were basically determined by the degree of ecosystem water limitation, which was quantified here using the ratio between atmospheric transpirational demand and soil water supply. Humid sites and/or periods were least responsive to any change in P as compared with moderately humid or dry sites/periods. We also found that NPP responded more strongly to doubling or halving of P amount and a seasonal shift in P occurrence than that to altered P frequency and intensity at constant annual amounts. The findings were highly robust across the four models especially in terms of the direction of changes and largely consistent with earlier P manipulation experiments and modelling results. Overall, this study underscores the widespread importance of P as a driver of change in ecosystems, although the ultimate response of a particular site will depend on the detailed nature and seasonal timing of P change.