Effects of tree species identity and soil origin on soil nematode communities and trophic composition in coniferous and broad-leaved forests.

Purpose: The effects of trees on soil nematode communities are related to nutrient cycles in forest ecosystems. We conducted greenhouse pot experiments to determine the effects of a single tree species for each of coniferous and broad-leaved tree on soil nematodes.Soils were collected from a coniferous plantation and broad-leaved forests. Seedlings of a coniferous tree (<italic>Cryptomeria japonica</italic>) and a broad-leaved tree (<italic>Quercus serrata</italic>) were planted in soils derived from each species. After 11 months, seedling biomass, soil properties, and ectomycorrhizal fungal colonization of <italic>Q. serrata</italic> were measured. Soil nematodes were morphologically identified to the genus/family level and differentiated by community and trophic composition.<italic>C. japonica</italic> root biomass was significantly higher than that of <italic>Q. serrata</italic> regardless of the soil and nematode community structures were significantly different between the species. The fungal: bacterial ratio and density of fungivorous nematodes were significantly higher in broad-leaved soils. Herbivorous nematodes increased significantly in <italic>C. japonica</italic> seedlings grown in broad-leaved soils. Structural equation modeling indicated that soil origin and tree species directly regulated nematode trophic compositions.Our findings suggest that tree species modify soil micro-food webs by affecting microbial abundance and nematode trophic composition. Specifically, <italic>C. japonica</italic>, with a larger root biomass, increased the number of herbivorous nematodes, whereas <italic>Q. serrata</italic>, with ectomycorrhizal fungal symbiosis, increased the number of fungivorous nematodes. Thus, tree species are tightly involved in shaping nematode communities in forest ecosystems through root traits and mycorrhizal types.Methods: The effects of trees on soil nematode communities are related to nutrient cycles in forest ecosystems. We conducted greenhouse pot experiments to determine the effects of a single tree species for each of coniferous and broad-leaved tree on soil nematodes.Soils were collected from a coniferous plantation and broad-leaved forests. Seedlings of a coniferous tree (<italic>Cryptomeria japonica</italic>) and a broad-leaved tree (<italic>Quercus serrata</italic>) were planted in soils derived from each species. After 11 months, seedling biomass, soil properties, and ectomycorrhizal fungal colonization of <italic>Q. serrata</italic> were measured. Soil nematodes were morphologically identified to the genus/family level and differentiated by community and trophic composition.<italic>C. japonica</italic> root biomass was significantly higher than that of <italic>Q. serrata</italic> regardless of the soil and nematode community structures were significantly different between the species. The fungal: bacterial ratio and density of fungivorous nematodes were significantly higher in broad-leaved soils. Herbivorous nematodes increased significantly in <italic>C. japonica</italic> seedlings grown in broad-leaved soils. Structural equation modeling indicated that soil origin and tree species directly regulated nematode trophic compositions.Our findings suggest that tree species modify soil micro-food webs by affecting microbial abundance and nematode trophic composition. Specifically, <italic>C. japonica</italic>, with a larger root biomass, increased the number of herbivorous nematodes, whereas <italic>Q. serrata</italic>, with ectomycorrhizal fungal symbiosis, increased the number of fungivorous nematodes. Thus, tree species are tightly involved in shaping nematode communities in forest ecosystems through root traits and mycorrhizal types.Results: The effects of trees on soil nematode communities are related to nutrient cycles in forest ecosystems. We conducted greenhouse pot experiments to determine the effects of a single tree species for each of coniferous and broad-leaved tree on soil nematodes.Soils were collected from a coniferous plantation and broad-leaved forests. Seedlings of a coniferous tree (<italic>Cryptomeria japonica</italic>) and a broad-leaved tree (<italic>Quercus serrata</italic>) were planted in soils derived from each species. After 11 months, seedling biomass, soil properties, and ectomycorrhizal fungal colonization of <italic>Q. serrata</italic> were measured. Soil nematodes were morphologically identified to the genus/family level and differentiated by community and trophic composition.<italic>C. japonica</italic> root biomass was significantly higher than that of <italic>Q. serrata</italic> regardless of the soil and nematode community structures were significantly different between the species. The fungal: bacterial ratio and density of fungivorous nematodes were significantly higher in broad-leaved soils. Herbivorous nematodes increased significantly in <italic>C. japonica</italic> seedlings grown in broad-leaved soils. Structural equation modeling indicated that soil origin and tree species directly regulated nematode trophic compositions.Our findings suggest that tree species modify soil micro-food webs by affecting microbial abundance and nematode trophic composition. Specifically, <italic>C. japonica</italic>, with a larger root biomass, increased the number of herbivorous nematodes, whereas <italic>Q. serrata</italic>, with ectomycorrhizal fungal symbiosis, increased the number of fungivorous nematodes. Thus, tree species are tightly involved in shaping nematode communities in forest ecosystems through root traits and mycorrhizal types.Conclusion: The effects of trees on soil nematode communities are related to nutrient cycles in forest ecosystems. We conducted greenhouse pot experiments to determine the effects of a single tree species for each of coniferous and broad-leaved tree on soil nematodes.Soils were collected from a coniferous plantation and broad-leaved forests. Seedlings of a coniferous tree (<italic>Cryptomeria japonica</italic>) and a broad-leaved tree (<italic>Quercus serrata</italic>) were planted in soils derived from each species. After 11 months, seedling biomass, soil properties, and ectomycorrhizal fungal colonization of <italic>Q. serrata</italic> were measured. Soil nematodes were morphologically identified to the genus/family level and differentiated by community and trophic composition.<italic>C. japonica</italic> root biomass was significantly higher than that of <italic>Q. serrata</italic> regardless of the soil and nematode community structures were significantly different between the species. The fungal: bacterial ratio and density of fungivorous nematodes were significantly higher in broad-leaved soils. Herbivorous nematodes increased significantly in <italic>C. japonica</italic> seedlings grown in broad-leaved soils. Structural equation modeling indicated that soil origin and tree species directly regulated nematode trophic compositions.Our findings suggest that tree species modify soil micro-food webs by affecting microbial abundance and nematode trophic composition. Specifically, <italic>C. japonica</italic>, with a larger root biomass, increased the number of herbivorous nematodes, whereas <italic>Q. serrata</italic>, with ectomycorrhizal fungal symbiosis, increased the number of fungivorous nematodes. Thus, tree species are tightly involved in shaping nematode communities in forest ecosystems through root traits and mycorrhizal types. [ABSTRACT FROM AUTHOR]