Global Change Biology:中大学者揭示气候变化对生态系统生产力存在着
8月7日Global Change BioLogy上在线发表中山大学生命科学大学院何芳良教授研究团队与美国加州大学洛杉矶分校、丹麦哥本哈根大学以及兰州大学等科研人员一起发表的关于气候变化对生态系统生产力该研究结果，团队成员储诚进教授为论文的第一作者，何芳良教授为共同作者之一。
通常认为气候因子(如温度和降雨)通过改变植物个体的生理生态过程影响着生态系统生产力。然而，2014年7月Michaletz等发表于Nature上的一篇论文认为气候变化尽管能够影响生态系统生产力，但这种影响是间接而非直接的。该研究认为气候通过影响林分的生物量和年龄从而对生产力施加影响，而气候的直接影响微乎其微。这个结论完全颠覆了学术界对该科学问题的认识。
中山大学生命科学大学院何芳良教授研究团队与来自美国加州大学洛杉矶分校(Megan Bartlett, Lawren Sack)、丹麦哥本哈根大学(Jacob Weiner)、法国CNRS(Jérôme Chave)以及兰州大学(王酉石)的科研人员一起，指出了Michaletz et al. (2014)工作中诸多根本性的错误，并采用合适的统计方法全面分析了相关的数据。新的研究结果显示气候因子不仅对生产力有着非常重要的直接影响，甚至还强于气候因子的间接影响。该研究的意义不仅仅是支持了之前的科学认识，更为重要的是为研究类似问题提供了新的理论框架和分析方法，为研究植物群落和生态系统如何响应气候变化提供了新的思路。
原文链接：
Does climate directly influence NPP globally?
原文摘要：
The need for rigorous analyses of climate impacts has never been more crucial. Current textbooks state that climate directly influences ecosystem annual net primary productivity (NPP), emphasizing the urgent need to monitor the impacts of climate change. A recent paper challenged this consensus, arguing, based on an analysis of NPP for 1247 woody plant communities across global climate gradients, that temperature and precipitation have negligible direct effects on NPP and only perhaps have indirect effects by constraining total stand biomass (Mtot) and stand age (a). The authors of that study concluded that the length of the growing season (lgs) might have a minor influence on NPP, an effect they considered not to be directly related to climate. In this article, we describe flaws that affected that study's conclusions and present novel analyses to disentangle the effects of stand variables and climate in determining NPP. We re-analyzed the same database to partition the direct and indirect effects of climate on NPP, using three approaches: maximum-likelihood model selection, independent-effects analysis, and structural equation modeling. These new analyses showed that about half of the global variation in NPP could be explained by Mtot combined with climate variables and supported strong and direct influences of climate independently of Mtot, both for NPP and for net biomass change averaged across the known lifetime of the stands (ABC = average biomass change). We show that lgs is an important climate variable, intrinsically correlated with, and contributing to mean annual temperature and precipitation (Tann and Pann), all important climatic drivers of NPP. Our analyses provide guidance for statistical and mechanistic analyses of climate drivers of ecosystem processes for predictive modeling and provide novel evidence supporting the strong, direct role of climate in determining vegetation productivity at the global scale.
作者： 储诚进与何芳良
