The responses of soil nematode assemblages to disturbance in Liaohe estuary wetlands

•Differences of nematode indices between soil layers were not distinct.•Responses of nematodes to disturbance varied with changes of season.•Plants impacted nematodes indirectly via alterations of abiotic characteristics.

To improve the knowledge of nematode communities in the Liaohe estuary, the spatiotemporal variations of free-living nematode communities (density, diversity and trophic structure) in the protected zone (PZ) and the development zone (DZ) were seasonally studied. Soil nematode communities were analysed at the depths of 0–10 and 10–20 cm. The results showed that bacterial feeder nematodes were the most abundant trophic groups in both depths and at both sites. Nematode abundance and plant-parasitic nematodes maturity index/maturity index in the DZ were higher than that in the PZ (p < 0.05); trophic diversity, Shannon index, fungivore/bacterivore ratio and Wasilewska index in the PZ were higher than those in the DZ (p < 0.05). No significant differences were found in nematode indices between soil layers. Structural equation modelling (SEM) revealed that season, plant biomass and soil properties explained 78% of the variation in soil nematode, and plant biomass controlled nematodes indirectly through affecting soil properties. In general, anthropogenic activities could affect nematode communities, but the degree of influence varied with seasonal change.