高寒草甸生态系统蚁丘对小型土壤节肢动物群落的影响

Effects of ant-hills on the community structure of soil microarthropods in an alpine meadow ecosystem

为查明高寒草甸中蚁丘对小型土壤节肢动物群落的影响,2018年5、7和10月分别在若尔盖高寒草甸内选取6个直径在30—35 cm间的蚁丘作为调查对象,并选取距相应蚁丘2 m处的点作为对照,采集蚁丘和对照的土壤样品,用Tullgren法分离小型土壤节肢动物。结果表明:(1)蚁丘可以明显改变高寒草甸小型土壤节肢动物群落组成结构,主要类群由螨类转变为跳虫;(2)蚁丘中的长角跳目、前气门亚目和甲螨亚目的个体密度均显著高于对照(P<0.05),但仅有甲螨亚目个体百分比在群落中所占比例显著高于对照(P<0.05);(3)蚁丘可以显著提高小型土壤节肢动物群落密度和多样性,尤其能够使部分菌食性跳虫(库跳属、隐跳属、符跳属)和腐食性螨类(布伦螨属、双瘤吸螨属、微奥甲螨属及下盾甲螨属)的个体数量大幅增加;(4)从5月到10月,小型土壤节肢动物群落的个体密度在蚁丘中呈先增加后下降的变化趋势(P<0.05),在对照中呈持续增加(P>0.05),而类群数和Shannon多样性指数在蚁丘和对照中均呈增加趋势,但仅在对照有显著差异(P<0.05);(5)小型土壤节肢动物的类群数、Shannon多样性指数与有机质含量呈显著正相关(P<0.05),个体密度与土壤容重呈显著负相关(P<0.05)。研究结果表明,蚁丘能够改变小型土壤节肢动物群落组成结构,并显著提高小型土壤节肢动物群落个体密度和多样性。

The objective of this study is to examine the effects of ant-hills on soil microarthropod communities in an alpine meadow ecosystem.Six ant-hills with diameter between 30 cm and 35 cm and six paired adjacent plots(with 2 m interval)as control were randomly selected in May,June and October 2018 in a Zoigêalpine meadow.Soil samples were collected from ant-hills and controls.Soil microarthropods were extracted from the soil samples for 48 h at 38℃using the Tullgren method in the laboratory.The results showed that(1)the ant-hills markedly changed the structure of soil microarthropod communities,i.e.,the dominant group shifting from mites to springtails.(2)The individual densities of the Entomobryomorph,Prostigmata and Oribatida in ant-hills were significantly higher than those in controls(P<0.05),but significant differences in the individual percentage between ant-hills and controls were only observed for Oribatida(P<0.05).(3)The significant increases were observed for the individual density and diversity of soil microarthropod communities in ant-hills(P<0.05),especially for the individual densities of some fungivorous springtails(such as Coloburella,Cryptopygus and Folsomia)and saprophagous mites(such as Brennandania,Biscirus,Microppia and Hypovertex).(4)The individual density of soil microarthropod communities increased then declined in ant-hills(P<0.05)but increased continually in controls(P>0.05)from May to October.The group number and Shannon index increased in both ant-hills and controls with significance only observed in controls(P<0.05).(5)The group number and Shannon diversity significantly and positively correlated with the soil organic matter content,but the individual density significantly and negatively correlated with soil bulk density.The results indicated that ant-hills could change the taxonomic composition structure,and increase the individual density and diversity of soil microarthropod communities.