The assembly and maintenance of biodiversity in multitrophic communities

由不断增长的人口和活动驱动的全球变化正在造成全球生物多样性的重新洗牌。动物、植物和微生物群落正在迅速变化，以应对人为压力，导致生物多样性的收益和损失。为了在不断变化的世界中预测和管理生物多样性，必须了解影响群落聚集（物种如何聚集）和生物多样性维持（生物多样性如何随时间持续）的因素。对当前和未来生物多样性的预测往往侧重于非生物选择的过程，而往往忽视了生物选择的重要性。非生物选择源于当地气候或其他非生物变量与物种耐受这些条件的能力之间的匹配。生物选择与物种是相互吸引还是相互排斥有关。因此，非生物选择和生物选择决定了哪种物种混合可以在一个地方持续存在。然而，生物选择影响群落建立的确切机制仍在研究中。生物选择可以在营养水平内（植物通过竞争相互排斥）或营养水平之间（植物的花朵与传粉者不相容）进行。营养和非营养相互作用对群落和生物多样性的影响很少被联合考虑。为了向前发展，生物多样性科学家必须发展一种整合营养和非营养相互作用的生态群落组合理论。网络方法用于描述多营养群落（具有一个以上营养水平的群落）中生物相互作用的复杂模式。生态网络是描述占据不同营养水平的物种之间成对相互作用的模式。在自然界中观察到的生态网络结构有很大的变化，但对这种变化的原因却知之甚少。我们的研究小组开发了一个概念和方法框架，以进一步了解多营养群落（即生态网络）中生物多样性组装和维持的基础过程。我们还开发了专业知识和技术来描述各种自然系统中的复杂生态网络结构：从植物-微生物，到植物-食草动物和植物-传粉者网络。拟议的研究计划的目标是建立在最近的理论，方法和技术发展，以确定形成生物多样性的过程。我们将通过结合实地实验和环境DNA测序来确定形成植物传粉媒介网络及其对人类干扰的恢复能力的“规则”。这些项目的结果将对我们预测昆虫传粉媒介多样性未来变化的能力产生重大影响，这对于减轻它们为人类提供的重要服务的丧失至关重要。

Global changes driven by continuously growing human populations and activities are causing a global reshuffling of biodiversity. Communities of animals, plants and microbes are rapidly changing in response to anthropogenic pressure, resulting in biodiversity gains and losses. To predict and manage biodiversity in a changing world, it is imperative to understand the factors affecting community assembly (how species come together) and biodiversity maintenance (how biodiversity persists through time). Predictions of current and future biodiversity often focus on the process of abiotic selection, while often neglecting the importance of biotic selection. Abiotic selection results from a a match between local climate, or other abiotic variables, and a species' ability to tolerate these conditions. Biotic selection relates to whether species attract or repel each other. Abiotic and biotic selection thus dictate which mix of species can persist together in one place. The exact mechanisms by which biotic selection influences the build up of communities, however, are still being investigated. Biotic selection can operate within a trophic level (plants excluding each other via competition) or between trophic levels (plant flowers that are incompatible with a pollinator). The influence of trophic and non-trophic interactions on communities and biodiversity are rarely considered jointly. To move forward, biodiversity scientists must develop a theory of ecological community assembly that integrates trophic and non-trophic interactions. Network approaches are used to describe complex patterns of biotic interactions in multitrophic communities (communities with more than one trophic level). An ecological network is a pattern describing pairwise interactions between species occupying different trophic levels. There is great variation in the structure of ecological networks observed in nature, but the causes of such variation are poorly understood. Our research group developed a conceptual and methodological framework to further our understanding of processes underpinning the assembly and maintenance of biodiversity in multitrophic communities (i.e., ecological networks). We also developed the expertise and technology to describe the structure of complex ecological networks across a variety of natural systems: from plant-microbe, to plant-herbivore and plant-pollinator networks. The goal of the proposed research program is to build on recent theoretical, methodological and technological developments to determine the processes shaping biodiversity. We will accomplish this by combining field experiments and environmental DNA sequencing to identify the "rules" that shape plant-pollinator networks and their resilience to human perturbations. Results from these projects will have a significant impact on our ability to predict future changes in insect pollinator diversity, which is essential to mitigate the loss of the important services they provide to humans.