Department of Terrestrial Ecology, Netherlands Institute of Ecology (NIOO-KNAW), Wageningen, The Netherlands.
Ecology Group, Department of Biology, University of Konstanz, Konstanz, The Netherlands.
Oecologia. 2020 Oct;194(1-2):237-250. doi: 10.1007/s00442-020-04749-y. Epub 2020 Oct 3.
Climate change causes species range expansions to higher latitudes and altitudes. It is expected that, due to differences in dispersal abilities between plants and soil biota, range-expanding plant species will become associated with a partly new belowground community in their expanded range. Theory on biological invasions predicts that outside their native range, range-expanding plant species may be released from specialist natural enemies, leading to the evolution of enhanced defence against generalist enemies. Here we tested the hypothesis that expanded range populations of the range-expanding plant species Centaurea stoebe accumulate fewer root-feeding nematodes than populations from the original range. Moreover, we examined whether Centaurea stoebe accumulates fewer root-feeding nematodes in expanded range soil than in original range soil. We grew plants from three expanded range and three original range populations of C. stoebe in soil from the original and from the new range. We compared nematode communities of C. stoebe with those of C. jacea, a congeneric species native to both ranges. Our results show that expanded range populations of C. stoebe did not accumulate fewer root-feeding nematodes than populations from the original range, but that C. stoebe, unlike C. jacea, accumulated fewest root-feeding nematodes in expanded range soil. Moreover, when we examined other nematode feeding groups, we found intra-specific plant population effects on all these groups. We conclude that range-expanding plant populations from the expanded range were not better defended against root-feeding nematodes than populations from the original range, but that C. stoebe might experience partial belowground enemy release.
气候变化导致物种向高纬度和高海拔地区扩张。预计由于植物和土壤生物区系之间扩散能力的差异，扩张范围的植物物种将在其扩展的范围内与部分新的地下群落相关联。生物入侵理论预测，在其原生范围之外，扩张范围的植物物种可能会免受专门的天敌的影响，从而导致对一般天敌的防御能力增强。在这里，我们检验了这样一个假设，即在扩张范围的种群中，扩张范围的植物物种百脉根积累的食根线虫比原始范围的种群要少。此外，我们还研究了百脉根在扩展范围的土壤中是否比在原始范围的土壤中积累了更少的食根线虫。我们在原始和新的范围的土壤中种植了来自三个扩展范围和三个原始范围的百脉根种群的植物。我们比较了百脉根的线虫群落与原产于两个范围的同属物种 C. jacea 的线虫群落。我们的研究结果表明，扩张范围的百脉根种群积累的食根线虫并不比原始范围的种群少，但与 C. jacea 不同的是，在扩张范围的土壤中，百脉根积累的食根线虫最少。此外，当我们研究其他食线虫群体时，我们发现同一种植物种群对所有这些群体都有影响。我们得出的结论是，来自扩展范围的扩张范围植物种群在防御食根线虫方面并不比来自原始范围的种群更好，但百脉根可能会经历部分地下天敌释放。
