URoL:EN: Emergence of function and dynamics from ecological interaction networks

生物系统在几乎所有的组织层次上都是由多样性来定义的--多样性不仅是其组成单位的多样性，而且是这些单位之间相互作用的多样性。了解这些系统的核心功能是如何从如此多样化的相互作用中产生的，是一个跨越从生理学和医学到生态学和环境工程等领域的根本挑战。长期以来，科学家们一直试图简化生物相互作用，将它们分为消极的（例如，竞争资源的竞争者）或正的（例如，在组织内协作的细胞）。然而，经过仔细观察，生物相互作用经常违反这种简单的二分法，而是“多价”：它们涉及同时发生的许多不同类型的相互作用。例子包括交换基因赋予抗生素抗性的细菌，同时竞争有限的营养物质，或者通过菌根网络共享碳的树木，即使它们竞争光和水。像这样的多价相互作用似乎在生物学中无处不在，但它们并不容易被纳入广泛用于研究系统尺度动力学的传统网络模型中。该项目旨在揭示生命规则，该规则支配着多价相互作用系统中的功能和动力学如何出现。研究人员将使用一个生态系统模型来解释这一规则：珊瑚礁。在珊瑚礁中，鱼类对藻类的消耗推动了各种鱼类种群的动态，并促进了珊瑚主导的生态系统状态。项目团队将严格测量鱼类物种之间的多价相互作用如何扩大到影响生态系统动态。在此过程中，该团队将开发数据收集技术和数学工具，为测量和理解复杂生物系统中最难以捉摸但最基本的方面之一提供一种可推广的方法：生物相互作用本身。该项目的研究结果将为全球5亿多人至关重要的珊瑚礁生态系统的管理提供信息。此外，该项目还将为来自历史上代表性不足的背景的学生创建一个技术本科生实习计划，并为当地公民科学家提供一个国际珊瑚礁监测计划。该项目团队将通过三个目标开发方法，发现生态相互作用的复杂网络中隐藏的结构，并利用该结构来了解生态系统层面的功能和对环境变化的反应。该项目的第一阶段将使用野外实验、新的摄像技术和计算机视觉来直接测量物种之间的生态相互作用，沿着一个新的算法建模框架来描述基于定量行为特征的相互作用行为。第二阶段将使用多种学习方法来搜索物种的“功能集群”的行为特征数据，并利用这种结构来推导系统的粗粒度动力学模型。这些模型将用于评估相互作用的结构如何驱动紧急生态系统功能。在第三阶段，该团队将使用数据驱动的动态模型来预测系统功能和状态将如何响应未来的环境变化。将开发粗粒度生态系统模型，以了解对环境扰动的长期、系统规模的响应。这些模型将纳入经验得出的进化率，以评估进化拯救影响生态系统如何应对变化的能力。高通量的数据收集技术，降维工具，在这项研究中开发的动态建模方法将有助于提供一个新的工具包，数据驱动的发现的动态结构的相互作用及其后果在复杂的生物systems.This奖项反映了NSF的法定使命，并已被认为是值得通过评估使用基金会的智力价值和更广泛的影响审查标准的支持。

Biological systems at virtually all levels of organization are defined by diversity – diversity not only of their constituent units, but also of the interactions among those units. Understanding how the core functions of these systems emerge from such diverse interactions is a fundamental challenge that cuts across fields ranging from physiology and medicine to ecology and environmental engineering. Scientists have long sought to simplify biological interactions by classifying them as either negative (e.g., competitors vying for resources) or positive (e.g., cells cooperating within tissue). Yet, upon close inspection, biological interactions regularly defy this simple dichotomy, and are instead “multivalent”: they involve many different types of interaction occurring simultaneously. Examples include bacteria that exchange genes conferring antibiotic resistance while competing for limiting nutrients, or trees that share carbon through mycorrhizal networks even as they compete for light and water. Multivalent interactions such as these appear to be ubiquitous in biology, but they are not easily incorporated into the conventional network models that are widely used to study system-scale dynamics. This project aims to reveal the Rule of Life that governs how function and dynamics emerge in systems of multivalent interactors. The researchers will decipher this Rule using a model ecosystem: coral reefs. In coral reefs, consumption of algae by fish drives dynamics of diverse fish populations and promotes a coral-dominated ecosystem state. The project team will rigorously measure how multivalent interactions among fish species scale up to influence ecosystem dynamics. In doing so, the team will develop data collection technologies and mathematical tools that will provide a generalizable methodology for measuring and understanding one of the most elusive, yet fundamental aspects of complex biological systems: biological interactions themselves. The project’s findings will inform management of coral reef ecosystems vital to over 500 million people worldwide. Moreover, the project will create a technical undergraduate internship program for students from historically underrepresented backgrounds and an international reef monitoring program that empowers local citizen scientists.Through three aims, the project team will develop methods that discover hidden structure in complex networks of ecological interactions and exploit that structure to understand ecosystem-level function and responses to environmental change. The first phase of the project will use field experiments, new camera technologies, and computer vision to directly measure ecological interactions among species, along with a novel algorithmic modeling framework to describe interaction behaviors based on quantitative behavioral traits. The second phase will use manifold learning methods to search behavioral trait data for “functional clusters” of species and exploit this structure to derive coarse-grained dynamical models of the system. These models will be used to evaluate how the structure of interactions drives emergent ecosystem function. In the third phase, the team will use data-driven dynamical models to project how system function and state will respond to future environmental change. Coarse-grained ecosystem models will be developed to understand long-term, system-scale responses to environmental perturbations. These models will incorporate empirically derived evolutionary rates to evaluate the capacity for evolutionary rescue to influence how ecosystems will respond to change. The high-throughput data-collection technologies, dimension reduction tools, and dynamical modeling methods developed in this research will help provide a novel toolkit for data-driven discovery of the dynamical structure of interactions and their consequences in complex biological systems.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.