城市化梯度下植物叶虫食率的变化格局及其影响机制研究

植食性昆虫对植物的取食是自然界最为常见的生态过程之一，也是生态系统中能量从低营养级类群向高营养级类群流动的重要途径。这一过程对植物的生长、繁殖、种间竞争、生物多样性及生态系统功能的维持都有至关重要的影响。经过数十年的研究，当前人们对自然生态系统中植物虫食的程度、变化规律和影响机制已经有了较为全面的了解。但在城市生态系统中，我们对这一过程的了解还相当有限，这已成为我们认识城市化生态效应的一块关键短板。本项目拟以植物叶虫食率作为表征植物-植食性昆虫相互作用强度的指标，借助毛虫模型实验和稳定性同位素分析等实验手段系统研究城市化梯度下植物自身属性造成的上行效应，捕食者造成下行效应以及景观特征对叶虫食率的影响，试图较为全面的回答叶虫食变异的影响机制。本项目的开展将为深入理解城市化对生物间相互作用的影响机制提供理论参考，同时对改进病虫害防控策略，维持城市生物多样性和生态系统服务功能也具现实意义。

Herbivory is one of the most common seen biotic interactions in nature, and also the most important pathway for energy flow from autotrophic plants to higher trophic levels. Herbivory has profound effects on plant growth, reproduction, interspecific competition, as well as the maintenance of biodiversity and ecological functions. Now, after decades of research, we already have a relatively comprehensive understanding about the variation and mediating factors of herbivory in natural ecosystems. But to date, we still know little about the pattern of herbivory in urban ecosystems, this is one of the key knowledge gaps on the ecological effects of urbanization. In this project, we try to understand the relative contribution of the top-down effect of predators, and the bottom-up effect of plant functional traits on the variation of herbivory rate under an urbanization gradient. With artificial caterpillar model experiment and stable isotope measurements, we try to understand the effects of urbanization on the ecological function of predators and mutualistic interactions, based on the viewpoint of leaf herbivory. The project will give us new insights on the ecological effects of urbanization on biotic interactions, it will also help us to improve the pest controlling strategy as well as the maintenance of biodiversity and ecological function in urban ecosystems.