Soil mesofauna may buffer the negative effects of drought on alien plant invasion

Although many studies have tested the direct effects of drought on alien plant invasion, less is known about whether drought affects alien plant invasion indirectly via interactions of plants with other groups of organisms such as soil mesofauna.
To test for such indirect effects, we grew single plants of nine naturalized alien target species in pot-mesocosms with a community of five native grassland species under four combinations of two drought (well-watered vs drought) and two soil-mesofauna-inoculation (with vs without) treatments.
We found that drought decreased the absolute and the relative biomass production of the alien plants, and thus reduced their competitive strength in the native community. Drought also decreased the abundance of soil mesofauna, particularly soil mites, but did not affect the abundance and richness of soil herbivores. Soil-fauna inoculation did not affect biomass of the alien plants but increased biomass of the native plant community, and thereby decreased ...

尽管已有大量研究探讨了干旱对外来植物入侵的直接效应，但学界对干旱是否会通过植物与其他生物类群（如土壤中型动物群（soil mesofauna））的相互作用间接影响外来植物入侵，仍知之甚少。为验证此类间接效应，本研究采用盆栽中型生态箱（pot-mesocosms）开展实验：设置两种干旱梯度（充分浇水 vs 干旱胁迫）与两种土壤中型动物群接种处理（接种 vs 不接种）的四种组合方案，培养9种归化外来目标物种的单株植株，并搭配5种本土草地植物组成的群落。研究结果表明，干旱胁迫会降低外来植物的绝对生物量与相对生物量，进而削弱其在本土群落中的竞争能力；同时干旱会降低土壤中型动物群的丰度，尤其是土壤螨类（soil mites）的种群数量，但对土壤植食性动物的丰度与物种丰富度无显著影响。土壤动物接种处理对外来植物的生物量无显著影响，但可提升本土植物群落的生物量，从而降低……