放牧对草地枯落物分解和土壤动物群落及其相互关系的影响

Effects of grazing on litter decomposition,soil faunal community and their relationships in grassland ecosystems

在草地生态系统中,枯落物作为介导土-草界面过程的重要环节,主要调控地上-地下生态系统物质循环与能量流动,其分解对土壤食物网和土壤生物营养结构具有显著影响。土壤动物是枯落物与土壤之间物质循环与能量流动的重要媒介,是枯落物分解与养分释放过程的主要调节者。近年来,国内外学者对枯落物分解与土壤动物多样性的研究逐步深入,取得大量的研究成果。本文通过综述国内外文献,从放牧对枯落物分解过程的影响、放牧对土壤动物的影响及放牧对枯落物分解与土壤动物关系的影响等三个方面,总结分析了放牧通过采食、践踏和排泄行为改变枯落物分解,间接影响土壤动物多样性,从而降低了土壤微食物网的复杂性。另外,食草动物对草地枯落物分解和土壤动物关系的影响复杂,且这种关系往往对放牧强度、放牧季节、家畜种类等做出响应,进而会影响到整个生态系统的结构和功能。

Litter is a main medium for soil-grass interaction in grasslands.As a key factor regulating the aboveground-belowground ecological processes,litter decomposition affects soil food web and trophic structure of soil organisms.Soil fauna are important mediators linking material circulation and energy flow between litter and soil,as the main regulators of litter decomposition and nutrient release.In recent years,the relationships between litter decomposition and soil fauna have been extensively investigated.Here,we summarized the effects of livestock grazing on litter decomposition,soil fauna,and their relationship.Grazing changes litter decomposition through feeding,trampling,and excretion behavior.Further,grazing indirectly affects soil fauna diversity,and thus reduces the complexity of soil micro-food web.In addition,the impacts of herbivores on the relationships between litter decomposition and soil fauna in grasslands are complex.Moreover,such relationship often responds to grazing intensity,grazing season and livestock species,and thus affects ecosystem structure and function.