虫食诱导的凋落叶性状变化对其在河流中分解和底栖动物定殖的影响

陆源凋落叶是河流碎屑型食物网的基础，其分解能影响全球C、N等营养元素的地球化学循环。凋落叶性状是影响其分解和河流底栖动物定殖的关键因子，而虫食是世界范围内引起凋落叶性状变化的主要因素。受气候变暖、城镇化、生物入侵等因子的干扰，虫食的危害程度和范围日趋严重，而以往研究忽视了其对河流生态系统功能和底栖动物群落的影响。基于此，本项目拟通过自然虫食干扰和人工模拟虫食情况下凋落叶性状的变化、凋落叶在野外河流的原位分解实验、底栖动物喂食实验等，系统深入研究：（1）对虫食敏感的凋落叶性状指标和植物种类；（2）虫食诱导的凋落叶性状变化对其在河流中分解的影响机制；（3）虫食诱导的凋落叶性状变化对底栖动物个体和群落结构的影响机制。预期成果将阐明虫食诱导的凋落叶性状变化对其在河流中分解和底栖动物定殖的影响机制，完善植物响应虫食的低纬度/高防御假说，为河岸林配置，森林和河流生态系统管理提供理论支撑。

Leaf litter fuel the detritus food web in streams, and the decomposition rate of leaf litter can affect the nutrient cycling of C and N within the watershed and even globally. Leaf litter trait is one keystone inherent factors that influencing the colonization of macroinvertebrates and microbes and the decomposition rate in streams. Terrestrial insect herbivory is one common factor that can affect leaf litter traits. Due to the stressors of climate warming, urbanization, and invasive species, the outbreak of insect pest is becoming more serious and the distribution range is projected to move at higher latitude and altitude areas. Therefore, investigating the impacts of insect herbivory induced leaf litter traits changes on the decomposition in streams plays an important role in the management and ecological restoration of stream ecosystems. We will measuring the change of leaf litter traits under natural and manipulated insect herbivory, conducting in situ leaf litter decomposition experiment, and doing laboratory macroinvertebrate feeding experiment to systematically investigate: (1) which leaf litter traits and plant species are sensitive to insect herbivory; (2) the mechanisms of insect herbivory induced leaf litter traits changes on the decomposition in streams; and (3) how insect herbivory induced leaf litter traits changes can affect individuals and the community of macroinvertebrates. Our findings are expected to explain how terrestrial insect herbivory induced leaf litter trait changes can affect leaf litter decomposition and macroinvertebrates in streams, adding new evidence to the low latitude high defense hypothesis, give suggestions to the selection of riparian plants, and provide theoretical and data support for the management and ecological restoration of streams.