松嫩平原湿地异质生境对土壤线虫群落特征的影响

Objective:Wetlands are recognized as highly productive ecosystems that play a crucial role in mitigating global climate change.The spresence of diverse habitats within wetlands directly or indirectly contributes to the enhancement of soil food webs.Moreover,the characteristics of vegetation have a significant impact on the structure and composition of soil biological communities,thereby influencing bottom-up effects. Methods:To investigate the impact of habitat heterogeneity on soil nematode communities in the Songnen Plain wetland,this study focused on five heterogeneous habitats in the region.These habitats were selected based on a preliminary investigation of plant community characteristics.The experiment was conducted in July 2022,and three plots were chosen from different habitats to analyze soil nematode communities,plants,and soil environmental factors within sample plots.Nematodes were extracted from the soil using an improved shallow dish separation and sucrose centrifugation method.The study analyzed the community composition structure,distribution characteristics,diversity,and nutrient groups of the nematodes. Results:Our findings indicate the following:(1)The soil nematodes in the study area are predominantly omnivorous-predators and plant-parasites.The habitat of L.chinensis exhibits the highest number of soil nematode individuals,Shannon index(H'),and Margalef species richness index(SR).The functional footprint of nematodes in the sample plot follows this order:L.chinensis>C.schmidtii>D.angustifolia>P.tenuiflora>Alkali habitat.(2)The channel index of soil nematodes in the Deyeuxia angustifolia habitat is significantly lower compared to other habitats.Fungal channels dominate the soil decomposition process in this habitat while bacterial channels dominate in others.(3)The ANOSIM test results demonstrate that habitat heterogeneity significantly influences the composition of four nutrient groups and the overall nematode community.Pearson correlation and redundancy analyses reveal that total phosphorus,soil moisture content,soil pH,and the importance value of hygrophytes in vegetation are the primary environmental factors affecting the structure and composition of soil nematode communities. Conclusions:Our research findings demonstrate that the heterogeneity of wetland habitat in the Songnen Plain has a significant impact on the community characteristics of soil nematodes.Specifically,the Leymus chinensis habitat stands out with the highest number of individuals,diversity,and richness of soil nematodes.Additionally,the stability of the Carex schmidtii plot is expected to play a crucial role in enhancing the restoration and natural improvement of wetlands due to its stable food web.These findings contribute to a deeper understanding of the processes and functions of the underground ecosystem in the wetlands of the Songnen Plain focuing on a soil biology perspective.