Grassland invasibility varies with drought effects on soil functioning

Although it is known that ecosystems are more susceptible to invasion when disturbed, our knowledge of the mechanisms involved remains limited. Recent studies indicate that disturbance-induced changes in soil nutrient availability could influence community invasibility, but the importance of this mechanism in the real world is not known. We tested the hypotheses that (i) exotic plant species profit from drought effects on soil functioning more than do natives; and (ii) grassland invasibility depends on soil responses to drought disturbance, which are greater in soils that exhibit a larger nutrient pulse following drought. This was tested in a series of grassland sites of contrasting management intensity which we subjected to an extreme (40-day) drought, after which seeds from four different plant families of native species and related exotics were added to soils originating from the drought and control treatments under greenhouse conditions. We also examined the performance of seeded na...尽管已有研究表明，生态系统在受到干扰时更易遭受生物入侵，但学界对其背后的相关作用机制仍知之甚少。近期研究显示，干扰诱导的土壤养分有效性变化可能影响群落可入侵性，但该机制在真实野外环境中的重要性仍未明确。本研究针对两项假说展开验证：其一，外来植物物种相比本土植物，更能从干旱对土壤功能的影响中获益；其二，草原群落可入侵性取决于土壤对干旱干扰的响应，且该响应在干旱后产生更强养分脉冲的土壤中更为显著。我们选取一系列管理强度存在差异的草原样地，对其施加为期40天的极端干旱处理；随后在温室环境中，将源自4个不同植物科的本土物种及对应外来物种的种子，播种于取自干旱组与对照组的土壤中开展实验。我们还对播种后的植株生长表现进行了观测……