Graf Nadin, Bucher Roman, Schäfer Ralf B, Entling Martin H
Institue for Environmental Sciences, University Koblenz-Landau, Fortstraße 7, 76829 Landau, Germany
Institue for Environmental Sciences, University Koblenz-Landau, Fortstraße 7, 76829 Landau, Germany.
Biol Lett. 2017 May;13(5). doi: 10.1098/rsbl.2017.0129.
Subsidies from adjacent ecosystems can alter recipient food webs and ecosystem functions, such as herbivory. Emerging aquatic insects from streams can be an important prey in the riparian zone. Such aquatic subsidies can enhance predator abundances or cause predators to switch prey, depending on the herbivores. This can lead to an increase or decrease of herbivores and herbivory. We examined the effects of aquatic subsidies on a simplified terrestrial food web consisting of two types of herbivores, plants and predators (spiders). In our six-week experiment, we focused on the prey choice of the spiders by excluding predator immigration and reproduction. In accordance with predator switching, survival of leafhoppers increased in the presence of aquatic subsidies. By contrast, the presence of aquatic subsidies indirectly reduced weevils and herbivory. Our study shows that effects of aquatic subsidies on terrestrial predators can propagate through the food web in contrasting ways. Thereby, the outcome of the trophic cascade is determined by the prey choice of predators.
来自相邻生态系统的补贴可以改变受援食物网和生态系统功能，例如食草作用。溪流中羽化的水生昆虫可能是河岸带的重要猎物。这种水生补贴可以增加捕食者的数量，或者导致捕食者转换猎物，这取决于食草动物。这可能导致食草动物数量的增加或减少以及食草作用的增强或减弱。我们研究了水生补贴对一个简化的陆地食物网的影响，该食物网由两种食草动物、植物和捕食者（蜘蛛）组成。在我们为期六周的实验中，我们通过排除捕食者的迁入和繁殖来关注蜘蛛的猎物选择。与捕食者转换猎物的情况一致，在有水生补贴的情况下，叶蝉的存活率有所提高。相比之下，水生补贴的存在间接减少了象鼻虫数量和食草作用。我们的研究表明，水生补贴对陆地捕食者的影响可以以相反的方式在食物网中传播。因此，营养级联的结果由捕食者的猎物选择决定。
