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Leaf Area Rather Than Photosynthetic Rate Determines the Response of Ecosystem Productivity to Experimental Warming in an Alpine Steppe
Author(s) -
Li Fei,
Peng Yunfeng,
Zhang Dianye,
Yang Guibiao,
Fang Kai,
Wang Guanqin,
Wang Jun,
Yu Jianchun,
Zhou Guoying,
Yang Yuanhe
Publication year - 2019
Publication title -
journal of geophysical research: biogeosciences
Language(s) - English
Resource type - Journals
eISSN - 2169-8961
pISSN - 2169-8953
DOI - 10.1029/2019jg005193
Subject(s) - environmental science , steppe , global warming , ecosystem , biomass (ecology) , primary production , productivity , forb , climate change , photosynthesis , carbon cycle , atmospheric sciences , leaf area index , terrestrial ecosystem , agronomy , ecology , grassland , biology , botany , macroeconomics , economics , geology
Gross primary productivity (GPP) plays an important role in mediating the feedback between land carbon (C) cycle and climate warming. However, knowledge about the mechanisms regulating the response of GPP to warming is still limited. Based on a four‐year field manipulative experiment, we examined the warming effects on GPP and the potential mechanisms in a typical alpine steppe on the Tibetan Plateau. Our results revealed that elevated temperature significantly increased GPP over the study period. The warming‐induced increase in GPP was driven by the increased leaf area index, which was derived from the increase in aboveground biomass of forb. By contrast, warming had no significant effects on photosynthesis per leaf area, likely due to the offset of warming‐induced increase in leaf nitrogen concentration and decrease in soil moisture. These results demonstrate that leaf area rather than leaf photosynthetic rate determines the response of ecosystem productivity to climate warming in this alpine steppe. More studies in other ecosystems are called for to test the observed mechanisms responsible for warming effects on GPP, so as to improve predictions of terrestrial C cycle under changing environment.