菌根共生对片段化森林群落中宿主植物优势度的作用机制

菌根共生对树木获取土壤中限制性磷素和适应贫营养环境发挥关键的作用。以往研究主要从环境过滤和竞争两方面证明片段化森林群落构建机制，普遍忽略了菌根共生对森林群落树种优势度和多样性的作用。本项目以千岛湖岛屿上不同菌根类型（丛枝菌根，外生菌根）和不同优势度树种作为研究对象，在小岛和大岛、岛屿边缘和内部分别测定树木菌根侵染和共生真菌群落的特征，分析岛屿面积效应和边缘效应对树木菌根特征的影响；通过调查样方树木群落和土壤磷含量等生境因子，比较生境片段化对不同菌根类型树种优势度影响的差异，最终探明菌根共生对片段化森林群落树种优势度的作用机制。本项目的实施，将加深我们对片段化森林群落演替和生物多样性维持机制的认识。

Mycorrhizal symbiosis play important roles in phosphorus acquisition and oligotrophic environment adaptation of trees. Previous studies on the mechanisms of community construction were mainly focus on environmental filtering and competition, which ignored the effects of mycorrhizal symbiosis on the dominance and diversity of tree species in fragmented forests. In this project, we will choose tree species with different mycorrhizal type (arbuscular mycorrhiza vs ectomycorrhiza) and different dominance in Thousand Island Lake region. In order to analyze how island area and edge effect will impact mycorrhizal symbiosis of trees, we will examine mycorrhizal colonization, the community character of mycorrhizal fungus for tree species at the edge and interior of small and large islands. We will also investigate plant community and habitat factors (including soil phosphorus availability) at each plot, and compare the different effects on dominance between AM and EM species. At last, we will explore the mechanism of mycorrhizal symbiosis effects on the dominance of host plant in fragmented forest communities. The implementation of this project will deepen our understanding on community succession and biodiversity maintenance of fragmented forests.