Interactive effects of elevated CO2, N deposition and climate change on plant litter quality in a California annual grassland
Interactive effects of elevated CO2, N deposition and climate change on plant litter quality in a California annual grassland
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DOI：
10.1007/s00442-004-1713-1
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发表时间：
2005-01-01
期刊：
影响因子：
2.7
通讯作者：
Vitousek, PM
中科院分区：
文献类型：
--
作者：
Henry, HAL;Cleland, EE;Vitousek, PM
虽然全球变化可以间接改变生态系统的养分动态，作为其对植物凋落物质量的影响的结果，全球变化对植物凋落物的相互作用在很大程度上仍然是未知的自然社区。我们研究了在加州一年生草地上进行的全因子实验中，CO2浓度升高，氮沉降，变暖和降水量增加对植物凋落物中有机化合物组成的影响。虽然木质素增加功能组内CO2浓度升高，这种影响减弱变暖的草和水的添加在杂类草。CO2诱导的功能组内的木质素的增加也被抵消的杂类草，其中含有较少的木质素比草的相对生物量的增加。因此，在CO2浓度升高的情况下，在地块水平上衰老组织的整体木质素含量没有净变化。硝酸盐增加N在草和杂类草凋落物，虽然这种影响被削弱水的补充。相对于功能组内N的变化，功能组优势的变化有一个小的影响，在情节水平上的整体凋落物N。硝酸盐添加剂对分解的影响最大，增加燕麦凋落物中木质素的损失，并与水的添加剂相互作用，以增加其他草的凋落物的分解。木质素的增加，导致CO2浓度升高分解没有影响，但CO2浓度升高增加燕麦凋落物的N损失。总体而言，全球变化的要素之间的相互作用是重要的影响植物凋落物化学的单因子效应。然而，除了在N的变化，凋落物质量在短期内对分解的影响不大。
Although global changes can alter ecosystem nutrient dynamics indirectly as a result of their effects on plant litter quality, the interactive effects of global changes on plant litter remain largely unexplored in natural communities. We investigated the effects of elevated CO2, N deposition, warming and increased precipitation on the composition of organic compounds in plant litter in a fully-factorial experiment conducted in a California annual grassland. While lignin increased within functional groups under elevated CO2, this effect was attenuated by warming in grasses and by water additions in forbs. CO2-induced increases in lignin within functional groups also were counteracted by an increase in the relative biomass of forbs, which contained less lignin than grasses. Consequently, there was no net change in the overall lignin content of senesced tissue at the plot level under elevated CO2. Nitrate additions increased N in both grass and forb litter, although this effect was attenuated by water additions. Relative to changes in N within functional groups, changes in functional group dominance had a minor effect on overall litter N at the plot level. Nitrate additions had the strongest effect on decomposition, increasing lignin losses from Avena litter and interacting with water additions to increase decomposition of litter of other grasses. Increases in lignin that resulted from elevated CO2 had no effect on decomposition but elevated CO2 increased N losses from Avena litter. Overall, the interactions among elements of global change were as important as single-factor effects in influencing plant litter chemistry. However, with the exception of variation in N, litter quality had little influence on decomposition over the short term.