祁连山草地蝗虫虫卵时空分布格局形成机制研究

Grasshoppers are the major components of grassland ecosystem, egg is one of the key grasshoppers developmental stage. The spatial distribution patterns of eggs and temporal dynamic of egg incubation period show a height variation because of restriction of soil hydrothermal and vegetation community characteristic in the outbreak area of grasshopper plagues in the Qilian mountain grassland. Egg appeared as a heterogeneous temporal-spatial distribution patterns from the interaction effects of vegetation and ambient soil hydrothermal conditions. To determine the formation mechanism of this pattern, we suggest conducting this project. The core of this study is grasshopper egg, the trail are vegetation community and soil hydrothermal changes from availability of water, temperature and vegetation nutrient. The process of incubation period and fertility of grasshopper egg, as well as their temporal-spatial distributions of pattern were studied through field investigation, monitoring and incubation. Main study contents include: effect of vegetation composition, structure and nutrient component, ecological adaptability of egg development and incubation period to soil water content and temperature, egg temporal-spatial distribution characteristic triggered by system coupling among vegetation and soil hydrothermal characteristics. This study will help us to clear the ecological formation mechanism of temporal-spatial distribution patterns of grasshopper egg, and inquire into the complex relationship between temporal-spatial distribution patterns of egg and vegetation community and soil water content and temperature, and the results and conclusions of this study will provide scientific basis for effectively forecasting and sustainably managing grasshopper plagues in the outbreak area of grasshopper plagues in the Qilian mountain grassland.

蝗虫是草地生态系统重要组分，卵是其关键的发育阶段。在祁连山草地蝗灾频发区，受植被群落和土壤水热等因子制约，蝗虫虫卵孵化动态和空间分布呈现高度时空分异特征，形成蝗虫虫卵高度异质性的时空分布格局。为明确该格局的形成机制，本项目通过野外调查、模拟、室内培养等途径，以草地蝗虫虫卵为研究核心，从植被群落和土壤水热特性几个层面，围绕成虫卵生殖力、孵化时间动态和空间分布格局的形成过程，主要研究植被群落组成、结构以及营养成分对成虫生殖力影响，探究虫卵孵化时间动态变异对土壤水热因子的生态适应性，解析植被和土壤水热特性系统耦合引发的虫卵时空分布特征，阐明祁连山草地蝗虫虫卵时空分布格局的形成机制，探讨虫卵时空分布格局的形成与植被-土壤水热特性的耦合关系，为祁连山草地蝗虫灾害的有效预测和可持续防控提供科学依据。

蝗虫是草地生态系统重要组分之一，在草地生态系统物质循环和能量流动中发挥了重要作用。卵是蝗虫关键的发育阶段，受植被群落和土壤环境因子制约，蝗虫虫卵孵化动态和空间分布呈现高度时空分异特征，进而导致草地蝗虫群落组成、发生数量呈现高度时空分异特征。本研究就杂草侵入、不同草地类型蝗虫多样性时空分布格局的形成及其驱动机制，优势种蝗虫生殖力以及繁殖特性的变异及其影响因素进行系统调查分析。课题通过4年野外调查/监测、原地模拟、室内测试、数据分析等工作，取得主要得到以下结论和成果：（1）高山草地杂草侵入导致土壤容重、pH、紧实度和水分以及植被群落特性发生变异。杂草入侵影响了蝗虫群落组成、改变物种丰富度，减少了物种多样性，但对蝗虫种群数量的影响取决于杂草种类。（2）水热资源状况、草地植被和地貌地势等特性决定的空间异质性对祁连山不同草地类型蝗虫群落组成、多样性和空间分布产生重要影响，不同草地类型时空分布分化明显。草地蝗虫繁殖力在不同种类间差异较大，亚洲小车蝗和狭翅雏蝗每头雌虫含卵囊数高于其它种类，红翅皱膝蝗和亚洲小车蝗卵囊中含有卵粒数大于其它种类。草地蝗虫栖息、产卵选择受其个体大小、植被结构和地表特性的影响。（3）蝗虫线粒体基因组大小为15, 285 bp-16, 143 bp，整个线粒体基因组包含了13个蛋白编码基因链，22个tRNA基因，2个rRNA以及1个重复区域；基因组呈现明显的AT偏好性。COX1基因的核苷酸变异程度最低，ATP8基因及其编码的氨基酸序列的变异率最高。（4）石灰岩山地不同植被恢复区地表节肢动物群落组成、结构、多样性及营养功能群的变异，主要受植被群落组成、数量和结构及其驱动形成的土壤理化特性、表层凋落物数量、质量和微生境条件的变异所致。（5）该课题共发表相关论文8篇，授权专利2件，培养硕士研究生2名。结果为解析草地蝗虫时空分布格局，丰富蝗虫多样性形成与维持理论，蝗虫可持续防控和退化生态系统健康维系提供科学依据。