Convergence of terrestrial plant production across global climate gradients

摘要

Variation in terrestrial net primary production (NPP) with climate is thought to originate from a direct influence of temperature and precipitation on plant metabolism. However, variation in NPP may also result from an indirect influence of climate by means of plant age, stand biomass, growing season length and local adaptation. To identify the relative importance of direct and indirect climate effects, we extend metabolic scaling theory to link hypothesized climate influences with NPP, and assess hypothesized relationships using a global compilation of ecosystem woody plant biomass and production data. Notably, age and biomass explained most of the variation in production whereas temperature and precipitation explained almost none, suggesting that climate indirectly (not directly) influences production. Furthermore, our theory shows that variation in NPP is characterized by a common scaling relationship, suggesting that global change models can incorporate the mechanisms governing this relationship to improve predictions of future ecosystem function.%净初级生产受到温度和降水的影响,但这是对植物代谢的一个直接效应、还是由生长季长度和植物生物质的变化所介导的一个间接生态效应？在这项研究中,Sean Michaletz等人建立了一个代谢比例理论,来测试直接和间接气候效应的相对重要性。通过将他们的模型应用到关于植物生产力的一个全球数据集,本文作者得出结论认为,间接效应能够解释气候对生产力的影响。温度和水分供应在局部尺度上是植物生理和生态系统代谢的基本驱动因素,但在全球尺度上气候通过植物年龄和林分生物质(该指标主要由植物最大尺寸驱动）间接影响净初级生产。