ObjectiveThe objectives of this study are to explore the impact factors of forest ecosystem water use efficiency and its response to climate change in the context of global climate change.
MethodWe used the Biome-BGC model optimized by PEST model parameters to explore the water use efficiency and its influencing factors of the Qianyanzhou forest ecosystem in different climate scenarios, Jiangxi Province of eastern China.
Result(1) The annual average temperature and maximum leaf area index of Qianyanzhou were significantly positively correlated with water use efficiency (P < 0.01). The correlation between precipitation and water use efficiency was not significant (P > 0.05). (2) The water use efficiency of different scenarios in Qianyanzhou was in the range of 2.09−3.71 g/kg and the mean was 2.90 g/kg. (3) Compared with CK (2.18−2.57 g/kg, mean 2.38 g/kg), double the concentration of atmospheric carbon dioxide scenario (C scenario, 2.38−3.41 g/kg, mean 2.90 g/kg), annual precipitation increased by 15% and double the concentration of atmospheric carbon dioxide scenario (PC scenario, 2.38−3.33 g/kg, mean 2.86 g/kg), temperature increased by 4 ℃ and double the concentration of atmospheric carbon dioxide scenario (TC scenario, 2.58−3.71 g/kg, mean 3.15 g/kg), annual precipitation increased by 15% and temperature increased by 4 ℃ scenario (PT scenario, 2.30−2.84 g/kg, mean 2.57 g/kg) and annual precipitation increased by 15%, temperature increased by 4 ℃ and double the concentration of atmospheric carbon dioxide scenario (PTC scenario, 2.70−3.60 g/kg, mean 3.15 g/kg) were significantly different. However, the annual precipitation increased by 15% scenario (P scenarion, 2.09−2.68 g/kg, mean 2.39 g/kg) and the temperature rised by 4 ℃ scenario (T scenario, 2.13−2.81 g/kg, mean 2.47 g/kg) had no significant effect on water use efficiency. (4) The water use efficiency between the PC scenario and the C scenario was not significant, and the TC scenario was significantly different from the water use efficiency of the C scenario.
Conclusion(1) The water use efficiency of Qianyanzhou forest ecosystem was affected by temperature and leaf area index. Scenario simulations showed that water use efficiency of Qianyanzhou can respond well to climate change. (2) There existed coupling effects of precipitation, temperature and atmospheric carbon dioxide concentration on water use efficiency. (3) The effect of warming on water use efficiency was greater than precipitation.
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