域控火烧对土壤线虫群落组成及结构的影响

Effects of Prescribed Fire on Community Composition and Structure of Soil Nematodes

野火及各种人为原因导致的火烧事件是生物圈常见的扰动方式,可通过多种途径影响土壤生物群落的组成及结构.本研究采用野外控制实验方法,研究域控火烧对中国北方弃耕草地土壤理化性质及土壤线虫群落组成及结构的影响.结果显示,域控火烧显著增加了土壤线虫的多度和物种丰富度,这种正效应与土壤养分含量、土壤微生物生物量及土壤pH存在显著的正相关关系.域控火烧显著提高了群落中植食性线虫的比例,显著降低了食真菌性线虫比例.以上实验结果表明,低强度火烧可通过资源与环境两种途径间接作用于土壤线虫群落,促进群落向更丰富和更多样转变.

Fire is the most common disturbance in many biomes and can affect the soil properties and soil biotic communities in a number of ways.We established a field manipulation experiment to investigate the effects of prescribed fire on the soil parameters and nematode community characteristics(abundance,genus richness,community diversity and ecological indices)in an old-field grassland of North China.The results showed prescribed fire significantly increased soil nematode abundance and genus richness and such changes correlated with soil nutrient content,microbial biomass and soil pH.The abundance of trophic groups in soil nematode community were considerably modified in prescribed fire plots due to the increase in proportion of plant parasites and reduced number of fungivore.These results suggest that prescribed fire results in a more abundant and diverse nematode community in old filed ecosystem and meanwhile such effects are indirect,i.e.,by increase of soil resources availability and change of soil pH.