Study on the trophic levels of soil macrofauna in artificial protection forests by means of stable nitrogen isotopes

Stable isotope technology is a very effective method for ecological research, and the stable nitrogen (N) isotope ( delta [sup 15] N) is widely used to investigate food chains and food webs in ecosystems. In this study, delta [sup 15]N was used to analyze the trophic level of soil macrofauna in three artificial protection forests. The forests selected for this study belonged to three North Shelterbelts located in the Daowai and Acheng districts of Harbin, Heilongjiang Province. The total N and ( delta [sup 15] of 12 soil macrofauna samples were investigated in the three sample forests in September 2010 and the corresponding values in soil, leaf litter and fine plant roots were also determined. The result showed that the trophic levels of the 12 soil macrofauna were from the second to the fourth level in the soil ecosystem. Furthermore, the low classification rank was an important reason for the large differences in trophic level.