Stronger effect of gastropods than rodents on seedling establishment, irrespective of exotic or native plant species origin

Experimental evidence about how generalist consumers affect exotic plant invasions is equivocal, but most tests have been limited to few plant species, single herbivore guilds, and single locations. Using a seed-addition experiment, we studied effects of gastropods and rodents on recruitment success of 37 exotic and 37 native plant species affiliated to three different functional groups (i.e. grasses, legumes and non-legume herbs). We replicated our seed addition x herbivore exclusion experiment at multiple grassland sites, located within a few km of each other in two regions, coastal central California (USA) and southern Saxony–Anhalt (Germany). The two study regions differed in climate, land-use, invasion history and species pools which allowed us to disentangle general from context-specific effects. In both regions, herbivory by gastropods had a stronger impact on the proportion of recruited seedlings and the proportion of recruited species than rodent herbivory, but this effect was ...

关于广食性消费者（generalist consumers）如何影响外来植物入侵的实验证据尚无定论，但绝大多数相关检验仅局限于少量植物物种、单一草食动物类群（herbivore guilds）以及单一研究地点。本研究通过种子添加实验（seed-addition experiment），探究了腹足类（gastropods）与啮齿类动物对隶属于3个不同功能群（functional groups，即禾草类、豆科类及非豆科草本类）的37种外来植物与37种本土植物的定植成功率（recruitment success）的影响。我们在两个区域的多个彼此相距仅数公里的草原样地中重复开展了种子添加×草食动物排除实验（herbivore exclusion experiment），这两个区域分别为美国加利福尼亚中部沿海地区与德国萨克森-安哈尔特州南部。两个研究区域在气候、土地利用方式、入侵历史以及物种库（species pools）方面均存在差异，这使得我们能够厘清效应的普遍性与情境特异性。在两个区域中，腹足类动物的取食对定植幼苗占比与定植物种占比的影响均强于啮齿类取食，但该效应……