苏北沿海不同土地类型土壤动物群落及其对凋落物分解的影响

明确苏北沿海不同土地类型土壤动物群落特征及其对凋落物分解动态的影响,选择江苏省东台林场不同土地利用类型(杨农复合林、杨树纯林、农田和草地)作为实验样地,采用网袋法对其开展定位观测研究,研究中共获得25 715个土壤动物标本,隶属于3门13纲35类; 在杨农复合林的网袋内土壤动物总个体数显著大于其他土地类型的,杨农复合经营在一定程度上刺激了中小型土壤动物数量的增长; 不同土地利用类型、不同孔径网袋凋落物残留率均存在显著性差异(p <0.01); 不同孔径网袋内凋落物分解残留率平均值为小孔(59.32%)>大孔(48.03%)>中孔(44.70%); 土壤动物的个体相对密度年均值(每克土壤含35.46～69.79个)和类群相对密度年均值(每克土壤含1.17～1.54目)均与凋落物分解残留率存在显著负相关; 各样地小型土壤动物对凋落物分解的平均贡献率(24.89%)均显著大于大型土壤动物的贡献率(0.70%)。因此,不同的土地利用类型导致样地凋落物输入的改变,可能影响土壤动物群落组成与结构,从而对凋落物分解产生一定的影响。

Effects of soil fauna on litter decomposition and its community structure under different land use patterns in coastal region of northern Jiangsu province

We conducted the investigation of soil fauna and its influence on litter decomposition and in total by different mesh sizes(5, 1 and 0.01 mm)litterbag under different land use patterns(i.e. poplar-crop integrated system, poplar plantation, cropland and grassland)in Dongtai forest farm of Jiangsu province. 25 715 individuals of soil meso- and macro-fauna were obtained through 4 samplings from 2012 to 2013, which belonged to 3 phyla, 13 classes and 35 orders. The mass remaining in the sites was in order of small mesh(59.32%)>coarse mesh(48.03%)>medium mesh(44.70%). Most of the diversity comparisons between sites differed significantly. Pielou biodiversity index was negatively correlated with litter remaining in coarse mesh litterbag(p<0.05), while the relationship between Shannon diversity index and litter remaining in different mesh sizes had no significant difference. The average contribution ratio of soil meso- and micro-fauna to litter decomposition(24.89%)was much bigger than that in the coarse mesh litterbag(0.70%). Our results suggest that land use changes alter the community structure of soil fauna, and then influence litter decomposition in this coastal region.