Food web structure provides biotic resistance against plankton invasion attempts
Food web structure provides biotic resistance against plankton invasion attempts
复制标题
食物网结构提供了针对浮游生物入侵尝试的生物抵抗力
作者：
A. Dzialowski;J. Lennon;V. Smith
人们普遍认为，土著社区通过生物相互作用提供对入侵者的抵抗力。然而，仍然有很多不确定的类型的生态过程和社区属性，有助于生物抗性。我们用实验性的围隔来研究浮游动物群落结构，无脊椎动物捕食和营养供应如何共同影响建立的外来水蚤lumholtzi。我们预测，建立将增加与本地浮游动物群落的生物量和多样性的下降，无脊椎动物捕食者（IP）将间接促进建立D。这是因为它的刺相对较长，可以阻止捕食者。此外，我们假设，营养供应的增加将增加藻类食物的可用性和促进建立。只有当原生浮游动物的生物量和多样性显著减少时，D.laurumholtzi才能成功入侵围隔生态系统。虽然无脊椎动物的捕食和资源供应改变了本地浮游动物群落的属性，但它们并不影响D。lumholtzi。总的来说，我们的研究结果与入侵水库中观察到的种群动态是一致的，其中D. dumplumholtzi往往只存在于夏末，与历史上的仲夏本地浮游动物种群下降相吻合。湖泊和水库可能更容易受到入侵，不仅是D。lumholtzi，但也受到其他南极物种，在夏末，当本地社区表现出与较低水平的生物抗性相关的特征。
It is generally accepted that native communities provide resistance against invaders through biotic interactions. However, much remains uncertain about the types of ecological processes and community attributes that contribute to biotic resistance. We used experimental mesocosms to examine how zooplankton community structure, invertebrate predation, and nutrient supply jointly affected the establishment of the exotic Daphnia lumholtzi. We predicted that establishment would increase with declining biomass and diversity of native zooplankton communities and that an invertebrate predator (IP) would indirectly facilitate the establishment of D. lumholtzi due to its relatively long predator-deterring spines. Furthermore, we hypothesized that elevated nutrient supply would increase algal food availability and facilitate establishment. Only when the biomass and diversity of native zooplankton were significantly reduced, was D.␣lumholtzi able to successfully invade mesocosms. Although invertebrate predation and resource supply modified attributes of native zooplankton communities, they did not influence the establishment of D. lumholtzi. Overall, our␣results are consistent with observed population dynamics in invaded reservoirs where D.␣lumholtzi tends to be present only during the late summer, coinciding with historic mid-summer declines in native zooplankton populations. Lakes and reservoirs may be more susceptible to invasion not only by D. lumholtzi, but also by other planktonic species, in the late summer when native communities exhibit characteristics associated with lower levels of biotic resistance.