Ecosystem respiration and net primary productivity after 8-10 years of experimental through-fall reduction in an eastern Amazon forest
Ecosystem respiration and net primary productivity after 8-10 years of experimental through-fall reduction in an eastern Amazon forest
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DOI：
10.1080/17550874.2013.798366
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发表时间：
2014-01-01
影响因子：
1.5
通讯作者：
Malhi, Yadvinder
中科院分区：
文献类型：
--
作者：
da Costa, Antonio C. L.;Metcalfe, Daniel B.;Malhi, Yadvinder
背景：亚马逊雨林可能会如何应对未来的降雨减少，人们对此很感兴趣。目的：我们描述了1公顷雨林小区的碳循环，并将这些结果与附近亚马逊东部未经改造的对照小区的结果进行了比较。方法：我们量化了净初级生产力(NPP)、自养(R-a)和异养呼吸的组成部分，并估计了总初级生产力(GPP，NPP和R-a之和)和碳利用效率(CUE，结果：TFR林表现出略低的NPP和略高的R-a，对照样地的森林线索为0.29+/-0.04，而TFR样地的森林线索为0.25+/-0.03。与4年前相比，TFR小区叶面积指数和小树生长恢复，土壤异养呼吸增加。结论：本分析验证和推广了4年前TFR处理的关键结果。结果表明，虽然森林在某些方面从长期干旱中恢复过来，但相对于未干旱的对照，它保持了更高的总体R-a，潜在地导致干旱森林充当二氧化碳的净来源。
Background: There is much interest in how the Amazon rainforest may respond to future rainfall reduction. However, there are relatively few ecosystem-scale studies to inform this debate.Aims: We described the carbon cycle in a 1 ha rainforest plot subjected to 8-10 consecutive years of ca. 50% through-fall reduction (TFR) and compare these results with those from a nearby, unmodified control plot in eastern Amazonia.Methods: We quantified the components of net primary productivity (NPP), autotrophic (R-a) and heterotrophic respiration, and estimate gross primary productivity (GPP, the sum of NPP and R-a) and carbon-use efficiency (CUE, the ratio of NPP/GPP).Results: The TFR forest exhibited slightly lower NPP but slightly higher R-a, such that forest CUE was 0.29 +/- 0.04 on the control plot but 0.25 +/- 0.03 on the TFR plot. Compared with four years earlier, TFR plot leaf area index and small tree growth recovered and soil heterotrophic respiration had risen.Conclusions: This analysis tested and extended the key findings of a similar analysis 4 years earlier in the TFR treatment. The results indicated that, while the forest recovered from extended drought in some respects, it maintained higher overall R-a relative to the undroughted control, potentially causing the droughted forest to act as a net source of CO2.