Determinants of species turnover
Four climate factors, two soil factors, and latitude factors were used to assess the effects of the environment and space. Partial RDA analysis indicated that the effects of environment and space were 54.09% and 13.84%, respectively, for overall faunas (Figure 6). The effects of pure climate on soil fauna composition were the strongest (31.27%), followed by pure soil factors (15.78%) and pure spatial factors (8.31%) for overall fauna order compositions (Figure 6a). Therefore, environmental factors and primarily climate, explained most of the variation in overall soil fauna order compositions.
For phytophage faunas, the effects of pure climate were 29.95%, pure soil were 9.65%, and pure spatial factors were 6.59% (Figure 6b). The effects of pure climatic factors were stronger than those of pure soil and pure spatial on soil animal composition, whereas for predacity faunas, the effects of pure climatic and soil factors were basically the same (Figure 6c). Moreover, the effects of pure climate factors on soil fauna order compositions for predacity faunas were the lowest, and the effects of pure soil and the spatially structured climatic factors were the highest (Figure 6).