Response of Soil Fauna Diversity to Agricultural Landscape Het-Erogeneity in the Middle and Lower Reaches of the Yellow River—A Case Study in Gongyi City, China

Soil fauna contribute to important ecological functions such as improving soil structure and promoting nutrient circulation. They are the common environmental indicators in agricultural landscape. Therefore, this study took Gongyi City, Henan Province, China, located in the middle and lower reaches of the Yellow River, as the study area, to explore the impact of multi-scale landscape heterogeneity on soil fauna diversity and the response of soil fauna to it. Our results showed that patch types and degree of fragmentation in the study area increased significantly with the increase of spatial scale. The diversity indices of soil fauna in different habitats showed that the Shannon-Wiener diversity index, Simpson’s diversity index, Pielou’s evenness index, and Margalef richness index were the lowest in farmland habitat. Diversity indices of artificial forests were higher than those of natural forests. Diversity indices of soil fauna under different geomorphic conditions showed that Pielou’s evenness index and Margalef richness index had significant differences under different geomorphic conditions (p < 0.05). The effects of multi-scale landscape heterogeneity on soil fauna diversity were different. In the 150 m buffer zone, soil fauna community composition and diversity indices were strongly correlated with patch richness index, patch richness density, and other landscape indices (p < 0.05). Meanwhile, the contribution rate of landscape index to soil fauna community composition were 45.05%, 32.5%, and 42% in farmland, plantation, and natural forest, respectively. Therefore, the 150 m buffer zone could be used as the characteristic response scale of soil fauna diversity. The multi-scale interaction of landform, habitat, and landscape also had a significant impact on soil fauna diversity.