Department of Terrestrial Ecology, Netherlands Institute of Ecology (NIOO-KNAW), P.O. Box 50, 6700 AB Wageningen, The Netherlands.
Ecology. 2011 Jun;92(6):1344-52. doi: 10.1890/10-1937.1.
Plant biomass and plant abundance can be controlled by aboveground and belowground natural enemies. However, little is known about how the aboveground and belowground enemy effects may add up. We exposed 15 plant species to aboveground polyphagous insect herbivores and feedback effects from the soil community alone, as well as in combination. We envisaged three possibilities: additive, synergistic, or antagonistic effects of the aboveground and belowground enemies on plant biomass. In our analysis, we included native and phylogenetically related range-expanding exotic plant species, because exotic plants on average are less sensitive to aboveground herbivores and soil feedback than related natives. Thus, we examined if lower sensitivity of exotic plant species to enemies also alters aboveground-belowground interactions. In a greenhouse experiment, we exposed six exotic and nine native plant species to feedback from their own soil communities, aboveground herbivory by polyphagous insects, or a combination of soil feedback and aboveground insects and compared shoot and root biomass to control plants without aboveground and belowground enemies. We observed that for both native and range-expanding exotic plant species effects of insect herbivory aboveground and soil feedback added up linearly, instead of enforcing or counteracting each other. However, there was no correlation between the strength of aboveground herbivory and soil feedback. We conclude that effects of polyphagous aboveground herbivorous insects and soil feedback add up both in the case of native and related range-expanding exotic plant species, but that aboveground herbivory effects may not necessarily predict the strengths of soil feedback effects.
地上和地下的天敌可以控制植物生物量和植物丰度。然而，人们对地上和地下天敌的影响如何相加知之甚少。我们将 15 种植物暴露于地上多食性昆虫草食动物和土壤群落的反馈作用，以及单独和组合的情况下。我们设想了三种可能性：地上和地下天敌对植物生物量的相加、协同或拮抗作用。在我们的分析中，我们包括了本地和系统发育上相关的外来扩张植物物种，因为与相关的本地植物相比，外来植物平均对地上草食动物和土壤反馈的敏感性较低。因此，我们研究了外来植物物种对天敌的较低敏感性是否也改变了地上-地下相互作用。在温室实验中，我们将六种外来和九种本地植物暴露于自身土壤群落的反馈、多食性昆虫的地上草食性或土壤反馈和地上昆虫的组合，并将地上和地下没有天敌的植物的地上和地下生物量与对照植物进行比较。我们观察到，对于本地和扩张范围的外来植物物种，地上草食性昆虫和土壤反馈的影响是线性相加的，而不是相互加强或相互抵消。然而，地上草食性的强度与土壤反馈之间没有相关性。我们的结论是，在本地和相关的扩张范围的外来植物物种中，多食性地上草食性昆虫和土壤反馈的影响是相加的，但地上草食性的影响不一定能预测土壤反馈的强度。
