The assembly and maintenance of biodiversity in multitrophic communities

由不断增长的人口和活动推动的全球变化正在导致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，导致生物多样性的得失。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(生物多样性如何经久不衰)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，而往往忽视生物选择的重要性。非生物选择的结果是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。生物选择关系到物种是相互吸引还是相互排斥。因此，非生物和生物的选择决定了哪种物种的混合可以在一个地方共存。然而，生物选择影响群落建立的确切机制仍在调查中。生物选择可以在营养水平内进行(植物通过竞争排除彼此)，也可以在营养水平之间进行(与授粉者不相容的植物花)。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装理论。网络方法被用来描述多营养群落(具有一个以上营养级别的群落)中生物相互作用的复杂模式。生态网络是一种描述占据不同营养水平的物种之间的成对相互作用的模式。自然界中观察到的生态网络结构有很大的差异，但这种差异的原因却鲜为人知。我们的研究小组开发了一个概念和方法框架，以促进我们对支撑多营养群落(即生态网络)中生物多样性组装和维护的过程的理解。我们还开发了专门知识和技术来描述各种自然系统的复杂生态网络的结构：从植物-微生物，到植物-草食动物和植物-传粉者网络。拟议研究计划的目标是建立在最近的理论、方法和技术发展的基础上，以确定形成生物多样性的过程。我们将通过将田间实验和环境DNA测序相结合来实现这一点，以确定形成植物传粉者网络的“规则”及其对人类干扰的恢复能力。这些项目的结果将对我们预测昆虫传粉者多样性未来变化的能力产生重大影响，这对于减轻昆虫传粉者为人类提供的重要服务的损失至关重要。

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.