水氮控制对荒漠草原中小型土壤动物群落的影响

Effect of water and N treatment on meso-and micro-fauna communities in soil of desert steppe

【目的】了解水氮控制对荒漠草原中小型土壤动物的影响,进而从土壤动物角度解读全球变化对荒漠草原的生态效应。【方法】2014年植物生长季,以内蒙古自治区乌兰察布市四子王旗短花针茅荒漠草原为研究对象,设置对照(CK,自然降雨状态)、减雨(R)、增雨(W)、施氮(N)、减雨施氮(R+N)和增雨施氮(WN)6个处理,观测不同处理中小型土壤动物群落和土壤环境参数的变化。【结果】短花针茅荒漠草原共捕获中小型土壤动物333 079.5只/m^2,隶属于节肢动物门的4纲10目47科,主要为弹尾纲(Collembola)、蛛形纲(Arachnida)和昆虫纲(Insecta);优势类群为疣虫兆科(Neanoridae)和等节科(Isotomidae),优势类群和常见类群构成了研究样地中小型土壤动物群落的主体。增雨、增雨施氮有助于提高短花针茅荒漠草原中小型土壤动物个体密度,减雨、减雨施氮处理减少中小型土壤动物个体密度,且水氮交互作用对中小型土壤动物个体密度影响表现显著,而对类群数无显著影响。短花针茅荒漠草原中小型土壤动物具有明显表聚性,各处理下0~10cm土层个体密度和类群数显著高于10~20cm土层(P<0.05)。【结论】在未来降雨增加和氮沉降的全球变化背景下,中小型土壤动物个体密度的变化可能会更大。

【Objective】This study investigated the effects of water and nitrogen treatment on soil mesoand micro-fauna communities in desert steppe to understand the ecological responses of desert steppe to global change.【Method】During growing season in 2014,the effects of control（CK,natural rainfall）,rainfall removal（R）,water addition（W）,N addition（N）,rainfall removal and nitrogen（R＋N）,and water addition and nitrogen（WN）on meso-and micro-fauna communities in soil of the Stipa breviflora desert steppe of Siziwang Banner,Inner Mongolia were studied.【Result】In Stipa breviflora desert steppe,a total of 333 079.5 ind/m-2 were captured,and they were classified into 4 phyla,10 orders and 47 families.Collembola,Arachnida and Insecta were the major groups.The communities were dominated by Neanoridae and Isotomidae.The communities mainly consisted of dominant and common groups.Water addition and water addition combined with N addition stimulated the density of soil meso-fauna in desert steppe while rainfall removal and rainfall removal combined with N addition reduced individual density of soil fauna.The inter-action between water and nitrogen had positive effect on soil fauna individual density,except for group richness.Soil meso-and micro-fauna communities in Stipa breviflora desert steppe had surface clustering feature,and individual number at 0-10 cm in all treatments was significantly higher than in 10-20 cm（P0.05）.【Conclusion】The density of meso-and micro-fauna is more sensitive than group richness with increasing precipitation and N deposition in future.