Marshland restoration benefits Collembola recruitment: a long-term chronosequence study in Sanjiang mire marshland, China

To examine the biodiversity restoration of marshlands after human-induced disturbances, a long-term chronosequence study of Collembola communities was completed that included cultivated treatment (marshes with 15 years of soybean cultivation; CU15), two restored treatments (with 6 and 12 years of agricultural abandonment; RE06 and RE12, respectively), and an intact marshland (IM) as a reference in the Sanjiang Plain, Northeastern China. Changes in the soil properties and Collembola communities under different treatments were analyzed. Soil parameters (i.e., soil organic carbon, available N, P and K, soil moisture) significantly increased from the cultivated treatment to the 6-year agricultural abandoned, and then 12-year agricultural abandoned treatment, indicating that the degraded soil began to recover after agricultural abandonment. The density, species richness and diversity of Collembola in RE12 were significantly higher than in RE06 and CU15, and even surpass the IM, indicating marshland restoration (after 12 years of agricultural abandonment) benefited recruitment and reconstruction of Collembola community. We found soil surface-dwelling Collembola recovered faster than eu-edaphic species, that is probably due to some common traits (i.e., parthenogenesis and fast dispersal) between epi- and hemi-edaphic species. The changes in the vegetation and soil properties during long-term soybean cultivation and agricultural abandonment were the key factors affecting the composition, density, and species richness of soil Collembola.