Earthworm Diversity and Related Environmental Factors in Three Habitat Types in Northern China

In the present study, we analyzed quantitative aspects of earthworms alongside soil and climate factors in three habitats, which include corn farms, vegetable fields, and grassland, in Northern China. Eighteen earthworm species belonging to seven genera and three families were found across habitat types in 57 plots. Amynthas modiglianii and Aporrectodea caliginosa trapezoides were the dominant species across the three habitat types. The average density of earthworms among the habitat types was 74.39 individuals/m2 with the vegetable fields having the highest density. The highest number of earthworm species was found on the corn farms. The vegetable fields were found to have the highest Shannon–Wiener (H' = 1.64) and Margalef (D = 1.06) indices. Species composition was similar among the vegetable fields but differed significantly in the corn farms. Most soil samples from collection sites were alkalescent. Temperature and vapor pressure were positively correlated with earthworm species diversity and abundance, but negatively correlated with species dominance. Elevation was negatively correlated with species diversity and abundance, but positively correlated with dominance. Some soil and precipitation factors showed non-significant correlations with species diversity. In addition, there was no significant correlation between the distribution ratio of juveniles and environmental factors.