Cesarz Simone, Ciobanu Marcel, Wright Alexandra J, Ebeling Anne, Vogel Anja, Weisser Wolfgang W, Eisenhauer Nico
German Centre for Integrative Biodiversity Research (iDiv) Halle-Jena-Leipzig, Deutscher Platz 5e, 04103, Leipzig, Germany.
Institute of Biology, Leipzig University, Deutscher Platz 5e, 04103, Leipzig, Germany.
Oecologia. 2017 Jul;184(3):715-728. doi: 10.1007/s00442-017-3893-5. Epub 2017 Jun 13.
The magnitude and frequency of extreme weather events are predicted to increase in the future due to ongoing climate change. In particular, floods and droughts resulting from climate change are thought to alter the ecosystem functions and stability. However, knowledge of the effects of these weather events on soil fauna is scarce, although they are key towards functioning of terrestrial ecosystems. Plant species richness has been shown to affect the stability of ecosystem functions and food webs. Here, we used the occurrence of a natural flood in a biodiversity grassland experiment that was followed by a simulated summer drought experiment, to investigate the interactive effects of plant species richness, a natural flood, and a subsequent summer drought on nematode communities. Three and five months after the natural flooding, effects of flooding severity were still detectable in the belowground system. We found that flooding severity decreased soil nematode food-web structure (loss of K-strategists) and the abundance of plant feeding nematodes. However, high plant species richness maintained higher diversity and abundance of higher trophic levels compared to monocultures throughout the flood. The subsequent summer drought seemed to be of lower importance but reversed negative flooding effects in some cases. This probably occurred because the studied grassland system is well adapted to drought, or because drought conditions alleviated the negative impact of long-term soil waterlogging. Using soil nematodes as indicator taxa, this study suggests that high plant species richness can maintain soil food web complexity after consecutive environmental perturbations.
由于当前的气候变化，预计未来极端天气事件的强度和频率将会增加。特别是，气候变化导致的洪水和干旱被认为会改变生态系统功能和稳定性。然而，尽管土壤动物群对陆地生态系统的功能至关重要，但关于这些天气事件对土壤动物群影响的知识却很匮乏。植物物种丰富度已被证明会影响生态系统功能和食物网的稳定性。在这里，我们利用一个生物多样性草地实验中发生的自然洪水，随后进行模拟夏季干旱实验，来研究植物物种丰富度、自然洪水和随后的夏季干旱对线虫群落的交互作用。自然洪水发生后的三个月和五个月，地下系统中仍可检测到洪水严重程度的影响。我们发现，洪水严重程度降低了土壤线虫食物网结构（K策略者的丧失）以及植食性线虫的丰度。然而，与单一栽培相比，在整个洪水期间，高植物物种丰富度维持了更高营养级的多样性和丰度。随后的夏季干旱似乎重要性较低，但在某些情况下逆转了洪水的负面影响。这可能是因为所研究的草地系统对干旱适应良好，或者因为干旱条件减轻了长期土壤渍水的负面影响。以土壤线虫作为指示类群，本研究表明，高植物物种丰富度可以在连续的环境扰动后维持土壤食物网的复杂性。
