Experimental determination of climate-change effects on above-ground and below-ground organic matter in alpine grasslands by translocation of soil cores
Experimental determination of climate-change effects on above-ground and below-ground organic matter in alpine grasslands by translocation of soil cores
复制标题
DOI：
10.1002/jpln.200321333
复制
发表时间：
2004-08-01
影响因子：
2.5
通讯作者：
Mirabella, A
中科院分区：
文献类型：
--
作者：
Egli, M;Hitz, C;Mirabella, A
我们采用土芯易位法研究了温度升高对凉爽高寒地区地上和地下植物质量和有机质的影响。将原状土芯从高山高地（海拔2525米）移位到林线附近的高山场地（海拔1895米），实现了3.3K的有效人工增温。从方法学角度来看，土芯移位是成功的。土芯移动到同一海拔的新地点后，地上和地下植被、容重和土壤骨架没有变化。这两个地点的土壤都是灰化土，具有相似的化学成分和粘土矿物学。然而，在海拔较低的地点，灰化过程似乎更为明显。因此，土核的易位可能导致对土壤形成约 10,000-13,000 年后建立的实际稳态的扰动。这可能影响了植被系统的适应性。因此，不能完全排除实验设计对结果的影响。在两年的实验期间，土芯从非常凉爽的地方转移到温暖的地方导致地上植物质量明显减少（约-45％）。人工增温后，表土（0-5厘米）的地下植物量显着减少（高达-50%）。可能的机制是根部减少了光合作用，从而减少了碳在地下的流动，土壤湿度的减少可能导致根部死亡（但这不是一个很可能的原因），或者辐射持续时间和通量的突然变化影响了根部的生长（也不是很可能）。快速的气候变化超出了地上和地下植物群的快速适应能力。植物量的减少是对气候变暖的短期反应还是长期反应仍不确定。根据梯度研究（同一地点的气候序列），我们假设植物生产力下降可能是短期影响。
We used the soil-core translocation method to investigate the effect of increased temperature on above- and below-ground phytomass and organic matter in cool alpine areas. The translocation of undisturbed soil cores from a high alpine site (2525 m a.s.l.) to an alpine site near the timberline (1895 m a.s.l.) achieved an effective artificial warming of 3.3 K. From a methodological point of view, the translocation of soil cores was performed successfully. Soil cores moved to a new site at the same altitude showed no change in above- and below-ground vegetation, bulk density, and soil skeleton. At both sites, soils were Haplic Podzols with a similar chemistry and clay mineralogy. At the lower elevation site, however, podzolization processes seemed to be more pronounced. As a consequence, the translocation of the soil cores probably led to a disturbance of the actual steady state that had been established after about 10,000-13,000 years of soil formation. This might have affected the adaptability of the vegetation system. Therefore, it cannot be fully excluded that the experimental design influenced the results. Translocation of soil cores from a very cool to a warmer site led to a distinct decrease in above-ground phytomass (about -45%) over the experimental period of two years. Below-ground phytomass significantly decreased (up to -50%) in the topsoil (0-5 cm) after artificial warming. Possible mechanisms are that roots reduced photosynthesis and hence C flow below-ground, a reduction of soil moisture that would have led to root death (not a very probable cause, however) or an abrupt change in the radiation duration and flux which affected root growth (also not very probable). Fast climate change exceeded the ability of the above-ground and below-ground phytomass to adapt quickly. Whether the decrease in phytomass was a short-term or a long-term response to climate warming remains uncertain. Based on a gradient study (climosequence at the same locality), we hypothesize that the decreased plant productivity might be a short-term effect.