Lucero Jacob E, Arab Nafiseh Mahdavi, Meyer Sebastian T, Pal Robert W, Fletcher Rebecca A, Nagy David U, Callaway Ragan M, Weisser Wolfgang W
Department of Biology York University Toronto ON Canada.
Terrestrial Ecology Research Group Department of Ecology and Ecosystem Management School of Life Sciences Weihenstephan Technical University of Munich Freising Germany.
Ecol Evol. 2020 Sep 11;10(19):10818-10828. doi: 10.1002/ece3.6737. eCollection 2020 Oct.
The enemy release hypothesis (ERH) attributes the success of some exotic plant species to reduced top-down effects of natural enemies in the non-native range relative to the native range. Many studies have tested this idea, but very few have considered the simultaneous effects of multiple kinds of enemies on more than one invasive species in both the native and non-native ranges. Here, we examined the effects of two important groups of natural enemies-insect herbivores and soil biota-on the performance of (native to Europe but invasive in the USA) and (native to the USA but invasive in Europe) in their native and non-native ranges, and in the presence and absence of competition.In the field, we replicated full-factorial experiments that crossed insecticide, competition, and biogeographic range (Europe vs. USA) treatments. In greenhouses, we replicated full-factorial experiments that crossed soil sterilization, plant-soil feedback, and biogeographic range treatments. We evaluated the effects of experimental treatments on and biomass.The effects of natural enemies were idiosyncratic. In the non-native range and relative to populations in the native range, escaped the negative effects of insect herbivores but not soil biota, depending upon the presence of ; and escaped the negative effects of soil biota but not insect herbivores, regardless of competition. Thus, biogeographic escape from natural enemies depended upon the enemies, the invader, and competition. By explicitly testing the ERH in terms of more than one kind of enemy, more than one invader, and more than one continent, this study enhances our nuanced perspective of how natural enemies can influence the performance of invasive species in their native and non-native ranges.
天敌释放假说（ERH）认为，相对于原生地，一些外来植物物种在非原生地的成功归因于天敌自上而下的影响减弱。许多研究检验了这一观点，但很少有研究考虑多种天敌同时对原生地和非原生地的多种入侵物种产生的影响。在这里，我们研究了两类重要的天敌——食草昆虫和土壤生物群落——对两种植物（原产于欧洲但在美国具有入侵性）和（原产于美国但在欧洲具有入侵性）在其原生地和非原生地以及有无竞争情况下表现的影响。在田间，我们重复了全因子实验，该实验交叉了杀虫剂、竞争和生物地理范围（欧洲与美国）处理。在温室中，我们重复了全因子实验，该实验交叉了土壤灭菌、植物 - 土壤反馈和生物地理范围处理。我们评估了实验处理对和生物量的影响。天敌的影响具有特异性。在非原生地且相对于原生地的种群，根据的存在情况，逃脱了食草昆虫的负面影响，但未逃脱土壤生物群落的负面影响；而无论有无竞争，都逃脱了土壤生物群落的负面影响，但未逃脱食草昆虫的负面影响。因此，从生物地理学角度逃脱天敌的影响取决于天敌、入侵物种和竞争情况。 通过明确地从不止一种天敌、不止一种入侵物种以及不止一个大陆的角度检验天敌释放假说，本研究提升了我们对于天敌如何影响入侵物种在其原生地和非原生地表现的细致入微的认识。
