青藏高原高寒草甸生态系统地上-地下食物链互作及其生态功能

Interactions between above and below-ground food chains plays an important role in ecosystem functioning. The accumulation of organic matter in alpine meadow in Tibet Plateau is abundant, but a large number of studies on effects of underground and aboveground processes on the accumulation of organic matter have been carried out in isolation in early stage, which limits our overall understanding of the mechanism of carbon and nitrogen cycling in this ecosystem. This project assumes that below-ground detritus food chains can indirectly affect plant community structure above-ground. The above-ground grazing food chain can regulate the quantity and quality of imported litter that affect the nutrient status of rhizosphere and components in detritus food chain. On the basis of the applicant's previous work. We propose to（1）make a study of interactions between fauna and flora of the typical alpine meadow system on the eastern edge of Tibet Plateau between aboveground and belowground grazing food chain (plant-caterpillar-spider) and detritus food chain (dung-earthworm-beetle) by observing community structure, productivity and effects of carbon and nitrogen cycles.（2）We comprehensive comparison and analysis of grazing food chain and detritus food chain and study of their effects on carbon and nitrogen processes in ecosystems. The results will help to understand ecological relationship between above and below ground, and further clarify mechanism of the carbon cycle of alpine meadow ecosystem in Tibet Plateau.

地上-地下食物链之间的相互作用对生态系统过程发挥着重要作用。青藏高原高寒草甸有机质积累丰富，但前期大量孤立地研究地下过程和地上过程对有机质积累的影响，限制了我们对该生态系统碳氮循环机制的全面认识。本项目假设地下的碎屑食物链可以间接影响地上的植物群落结构，地上的牧食食物链可以调控输入地下凋落物的数量和质量影响根际的养分状况以及碎屑食物链的各个组分。申请人在前期工作基础上，拟：（1）开展青藏高原东缘典型高寒草甸系统地上牧食食物链（植物-毛虫-蜘蛛）和地下碎屑食物链（牛粪-蚯蚓-步甲）动植物间的相互作用对群落结构、生产力以及碳氮循环影响的观测；（2）综合比较和分析牧食食物链和碎屑食物链，研究它们对生态系统碳氮过程的影响。研究结果有助于理解地上地下的生态学联系，并进一步阐明青藏高原高寒草甸生态系统碳循环的机制。

不同物种间营养关系对生态功能影响的研究是当前生态学研究的重要领域，地上-地下食物链（牧食食物链和碎屑食物链）互作背景下植物生长的响应如何是该研究的重要研究对象。本项目假设地下的碎屑食物链可以间接影响地上的植物群落结构，地上的牧食食物链可以调控输入地下凋落物的数量和质量影响根际的养分状况以及碎屑食物链的各个组分。我们研究了（1）青藏高原东缘典型高寒草甸系统地上牧食食物链（植物-毛虫-蜘蛛）和地下碎屑食物链（牛粪-蚯蚓-步甲）动植物间的相互作用对群落结构、生产力以及碳氮循环的影响；（2）综合比较和分析了牧食食物链和碎屑食物链，明确它们对生态系统碳氮过程的影响。这些研究结果有助于理解地上地下的生态学联系，并进一步阐明青藏高原高寒草甸生态系统碳循环的机制。