Linking nematode trophic diversity to plantation identity and soil nutrient cycling

Abstract

Ecological services provided by forest plantations depend on soil biodiversity, which encompasses taxonomic and functional diversity. These diversity components may respond specifically to environmental changes with consequences for soil functions. Given the large differences in plant-derived resource input between coniferous and broadleaved plantations, we investigated their impact on nematode species and trophic diversity, and on the soil nutrient cycling. The establishment of plantations (Larix gmelinii, Pinus tabuliformis, and Cercidiphyllum japonicum) 30 years ago led to a 31 %-37 % reduction in nematode species diversity, which is connected with decreased microbial biomass in soil. The reduced species diversity, however, was not linked to the cycling of organic matter, nitrogen, or phosphorus. Coniferous plantations (Larix gmelinii and Pinus tabuliformis) reduced nematode trophic diversity (34 %-55 %), indicating a strong decline in herbivorous and omnivorous-predatory groups of the food webs. This decline was primarily attributed to moisture limitations and reduced litter quality, and decreased nutrient cycling within the coniferous plantations. Conversely, the broadleaved plantation (Cercidiphyllum japonicum) maintained a complex nematode trophic structure with intensive nutrient cycling. Consequently, the trophic functional traits of nematode communities were determined by resource availability and linked to nutrient cycling in soil after plantation establishment.

Keywords

• Plantation types
• Soil nematode
• Soil biodiversity
• Trophic diversity
• Soil nutrients