The return of the trophic chain: fundamental vs realized interactions in a simple arthropod food web

Our research hypothesis is that increasing the number of species that are known to interact when no alternative food is available will increase the number of realized links in the more complex community. To address this question, we explore how pairwise trophic interactions between species are modified by the inclusion of other species in a simple community. We found that increasing the number of potential interactions did not result in more complex realized community modules. Instead, all communities were reduced to one or two linear trophic chains. Our results show that trophic links assumed to occur when species are assembled in pairs do not necessarily occur when other components of the community are present.

本研究假设认为，在无替代食物供应的情况下，已知能够相互作用的物种数量增加，将导致更为复杂群落中实现链接的数量上升。为解答此问题，我们探讨了在简单群落中引入其他物种如何影响物种间的成对营养相互作用。研究发现，增加潜在相互作用的数量并未导致实现群落模块的复杂性增加。相反，所有群落均简化为一至两条线性营养链。我们的结果表明，当物种以成对形式聚集时假定的营养链接，在群落的其他组成部分存在时未必会发生。