Ecology. 2014 Jan;95(1):123-31. doi: 10.1890/13-0270.1.
Peatlands are important sinks for atmospheric carbon (C), yet the role of plant functional types (PFTs) for C sequestration under climatic perturbations is still unclear. A plant-removal experiment was used to study the importance of vascular PFTs for the net ecosystem CO2 exchange (NEE) during (i.e., resistance) and after (i.e., recovery) an experimental drought. The removal of PFTs caused a decrease of NEE, but the rate differed between microhabitats (i.e., hummocks and lawns) and the type of PFTs. Ericoid removal had a large effect on NEE in hummocks, while the graminoids played a major role in the lawns. The removal of PFTs did not affect the resistance or the recovery after the experimental drought. We argue that the response of Sphagnum mosses (the only PFT present in all treatments) to drought is dominant over that of coexisting PFTs. However, we observed that the moment in time when the system switched from C sink to C source during the drought was controlled by the vascular PFTs. In the light of climate change, the shifts in species composition or even the loss of certain PFTs are expected to strongly affect the future C dynamics in response to environmental stress.
泥炭地是大气碳 (C) 的重要汇，但在气候胁迫下，植物功能型 (PFTs) 对碳封存的作用仍不清楚。采用植物去除实验研究了在实验干旱期间（即抵抗期）和之后（即恢复期），维管 PFTs 对净生态系统 CO2 交换 (NEE) 的重要性。PFTs 的去除导致 NEE 减少，但在微生境（即丘和草坪）和 PFTs 类型之间，减少的速率有所不同。石南去除对丘中的 NEE 有很大影响，而禾本科植物在草坪中起主要作用。PFTs 的去除并不影响干旱后的抵抗或恢复。我们认为，在所有处理中唯一存在的泥炭藓（Sphagnum mosses）对干旱的响应超过了共存的 PFTs。然而，我们观察到，在干旱期间，系统从碳汇切换到碳源的时间点是由维管 PFTs 控制的。在气候变化的背景下，物种组成的变化，甚至某些 PFTs 的丧失，预计将强烈影响未来对环境胁迫的碳动态响应。
