甘南高寒草甸土壤线虫营养功能群的地统计学分析

Geostatistical Analysis of Nematode Trophic Function Groups in Alpine Meadow of Ganan Region

土壤线虫是土壤生态系统的重要指示生物。研究高寒草甸土壤线虫营养功能群空间分布格局特征,有助于揭示土壤线虫分布对高寒草甸生态因子变化的响应。2019年7月中旬,采用网格法(1.0 m×0.5 m)研究5.0 m×4.0 m尺度土壤层(0~20 cm)土壤线虫营养功能群空间特征。采用改良湿漏斗法,共获得土壤线虫1830条,隶属于49属,土壤线虫个体平均密度以50 g干土计量为63.2条,其中,绕线属(Plectus)和拟丽突属(Acrobeloides)为优势类群。土壤线虫以食细菌线虫、植物寄生线虫为主。土壤线虫营养功能群变异系数介于64.26%~107.69%(n=38)之间,存在较强的变异性。食真菌线虫与食细菌线虫(P<0.001)、食真菌线虫与植物寄生线虫(P<0.001)间空间分布均存在显著相关性。地统计分析显示,土壤线虫营养功能群的空间相关范围存在明显差异,有效变程介于0.50~27.07 m之间,其67.26%~99.79%的变异与空间自相关过程有关。食细菌土壤线虫分布格局呈较均匀的斑块镶嵌结构,斑块较小;非食细菌土壤线虫呈斑块连接或斑块镶嵌结构,斑块较大且斑块间过渡明显,表明土壤线虫小尺度明显的斑块结构可能是高寒草甸受干扰后的一种常见分布模式,并受多种因素影响。

Soil nematodes are an import indicator of soil ecosystem.Exploring the characteristics of the spatial distribution pattern of soil nematode trophic function groups in alpine meadows is helpful to reveal the response to the change of alpine meadow ecological factors.In the middle of July 2019,the spatial characteristics of soil nematode trophic function groups in 5.0 m×4.0 m scale soil layers(0﹣20 cm)were studied by the grid method(1.0 m×0.5 m).Using modified wet funnel method,a total of 1830 soil nematodes were obtained,belonging to 49 genera,with an average of 63.2 soils nematodes per 50 g of dry soil,Plectus and Acrobeloides were the dominant groups;soil nematodes were mainly bacterivorous nematodes and plant parastic nematodes.The variable coefficient of soil nematode trophic function groups was between 64.4%﹣100.6%(n=38 soil samples),and had a strong variability.There was a significant correlation between the spatial distribution of fungivorous and bacterivorous nematodes(t=0.415,P<0.001),fungivorous and plant parastic nematodes(t=0.437,P<0.001).Geostatistical analysis showed that the spatial correlation range of the soil nematode trophic function group had significant difference.The effective variable range was between 0.50 to 27.07 m,and 67.26%to 99.79%of the variation was related to the spatial autocorrelation process.The distribution pattern of bacterivorous soil nematodes was a relatively uniform patch mosaic structure,and the patches are small;non-bacterivorous soil nematodes were patch-connected or patch-mosaic,with large patches and obvious transitions between patches,indicating that that the small-scale obvious patch structure of soil nematodes may be a common distribution pattern in alpine meadow after being disturbed,and affected by many factors.