Ecosytem functionning at the crossroad of biogeography and community ecology

生态学家一直对生物多样性的空间分布着迷。温度在大的生物地理梯度上直接影响许多生态系统过程，因为它影响生物速率。气候也是许多物种范围和生态互动的重要驱动因素。然而，在这些事实之间的十字路口发现了一个基本的、仍然没有得到回答的问题：生物多样性的分布和正在发生的群落生态在多大程度上影响着生态系统功能的全球分布？我的研究计划的长期目标是发展理论，以了解和预测生物多样性分布和生态系统在生物地理空间尺度上的功能。更具体地说，我将研究这样一个假设，即生态相互作用结构的空间变化在生物地理尺度上制约着生态系统生产力，与温度对生物速率的直接影响协同作用。我的具体目标是：i)发展一种数学形式来表示元生态系统相互作用网络的结构；ii)通过对其维度的分析来综合元生态系统的复杂性；iii)形式化并检验营养调节的温度依赖性的定量理论。 我将整合不同的方法论方法来实现我的目标，从数学建模到实验和实地观察。在项目1中，我将重建横跨北极的直接和间接生态相互作用网络。我将在分布在坡度上的地点进行实地采样，以记录植物-食草动物、植物-传粉者和捕食者-猎物的相互作用，我将把这些相互作用与通过动物迁徙和觅食进行空间交换的知识结合起来。在项目2中，我将调查元生态系统的维度。我将量化描述整个北欧柳树-盖勒-寄生蜂网络结构变化所需的潜在变量的数量。在项目3中，我将开发和测试营养调节的温度依赖性的定量理论。我将使用栖息在紫色猪笼草叶子上的微生物食物网来对该模型进行参数化，并进行实验来检验其定量预测。该项目的优势是基于生物地理学、群落生态学和生态系统生态学的整合。我将发展的形式主义将使该领域超越‘网络网络’的简单化观点。元生态系统是最复杂的生态结构之一，因为它们整合了空间、时间和相互作用，我将量化它们的维度，以挑战群落生态是一团糟的观点。最后，我开发的理论对于理解气候变化和生物多样性丧失对生态系统功能的联合影响至关重要。

Ecologists have always been fascinated by the spatial distribution of biodiversity. Temperature impacts directly many ecosystem processes over large biogeographical gradients because it affects biological rates. Climate is also an essential driver of many species ranges and ecological interactions. At the crossroad between these facts is however found a fundamental, and still unanswered, question: to what extent the distribution of biodiversity, and the community ecology taking place, is influencing the global distribution of ecosystem functioning? The long-term objective of my research program is to develop theory to understand and predict biodiversity distribution and ecosystem functioning at biogeographical spatial scales. More specifically, I will investigate the hypothesis that the spatial variation of the architecture of ecological interactions is constraining ecosystem productivity at the biogeographical scale, in synergy with the direct effect of temperature on biological rates. My specific objectives are: i) develop a mathematical formalism to represent the architecture of metaecosystem interaction networks; ii) synthesize the complexity of metaecosystems with analysis of their dimensionality; iii) formalize and test quantitative theory of temperature-dependence of trophic regulation. I will integrate different methodological approaches to reach my objectives, from mathematical modeling to experiments and field observations. In project 1, I will reconstruct the network of direct and indirect ecological interactions across the Arctic. I will conduct field sampling at sites spread across the gradient to document plant-herbivore, plant-pollinator and predator-prey interactions, which I will integrate with knowledge of spatial exchanges by migration and foraging of animals. In project 2, I will investigate the dimensionality of metaecosystems. I will quantify the number of latent variables required to describe the variation in the structure of willows-gallers-parasitoids networks across northern Europe. In project 3, I will develop and test a quantitative theory of temperature-dependence of trophic regulation. I will use the microbial food web inhabiting the leaves of the purple pitcher plants to parameterize the model and conduct experiments testing its quantitative predictions. The strength of this program is based upon the integration of biogeography, community ecology and ecosystem ecology. The formalism I will develop will bring the field beyond the simplistic view of 'networks of networks'. Metaecosystems are among the most complex ecological structures because they integrate space, time and interactions and I will quantify their dimensions to challenge the view that community ecology is a mess. Finally, the theory I develop will be critical to understand the joint effects of climate change and biodiversity loss on ecosystem functioning.