Estimating function of earthworm communities based on stoichiometry

人类活动正在改变全球生态系统和气候中的氮磷循环。蚯蚓是改变凋落物分解和土壤物理结构的土壤生态系统工程师。气候变化和大气氮沉降和施肥对生态系统氮磷循环的干扰可能会改变土壤动物，特别是蚯蚓的群落结构，因为氮磷通常是陆地栖息地的限制性营养物质。研究了土壤和蚯蚓的N、P含量，并试图估算NP平衡扰动对生态系统水平的影响。蚯蚓的存在大大提高了土壤氮矿化率，表明蚯蚓不仅是土壤微生物，而且是氮素驱动者。野外条件下莎草叶片的脱落促进了从根系渗出开始的土壤微食物网的形成，进而观察了土壤细菌和杆菌线虫的变化。氮矿化作用增强。在田间微观条件下，叶片品质影响蚯蚓的生长，体氮磷与蚯蚓的生长也存在良好的相关关系。表观蚯蚓生长速度快，氮磷含量低，而内源蚯蚓生长速度慢，氮磷含量高。因此，氮磷是蚯蚓群落结构的重要决定因素。

Human activities are now changing global nitrogen and phosphorus cycling in ecosystem as well as climate. Earthworms are soil ecosystem engineers modifying litter decomposition and soil physical structures. Climate change and disturbances in ecosystem cycling of N and P due to atmospheric nitrogen deposition and fertilization may change community structure of soil animals, especially, earthworms, because N and P are often limiting nutrients in terrestrial habitat. I studied N and P contents in soil and earthworms and tried to estimate ecosystem level effects of disturbance in NP balance.Soil N mineralization rates were greatly enhanced by the presence of earthworms, thus not only soil microorganisms but also earthworms are nitrogen driver. Defoliation of Sasa leaves in a field condition promoted soil micro-food web starting from root exudation, and then soil bacteria and bactrivorus nematodes were observed to change. Finally nitrogen mineralization was enhanced.Leaf quality affected earthworm growth in a field microcosm condition, and also there was a good correlation between body N:P and growth of Japanese earthworms. Epigeic earthworms had high growth rate and low N:P, and in contrast to this, endogeic species are slow grower and had high N:P. N and P are thus important determinant for community structure of earthworms.