Nematode biomass changes along an elevational gradient are trophic group dependent but independent of body size

• Published in: Global change biology Vol. 29; no. 17; pp. 4898 - 4909
• Main Authors: Li, Guixin, Wilschut, Rutger A., Luo, Shuaiwei, Chen, Han, Wang, Xiangtai, Du, Guozhen, Geisen, Stefan
• Format: Journal Article
• Language: English
• Published: England Blackwell Publishing Ltd 01.09.2023
• Subjects: altitude; Animals; bacterivores; Biomass; biotic and abiotic factors; Body Size; China; climate change; community‐weighted mean; Ecosystem; Environmental changes; fungivores; global change; Grasslands; Moisture content; Nematoda; nematode biomass; Nematodes; omnivores; Properties; Sensitivity; Soil; Soil chemistry; Soil pH; Soil properties; Soil temperature; Soil water; soil water content; temperature; Tibetan grasslands; trophic levels; trophic sensitivity; Water; Water content; China; trophic sensitivity; Tibetan grasslands; nematode biomass; biotic and abiotic factors; community-weighted mean; climate change
• ISSN: 1354-1013; 1365-2486; 1365-2486
• DOI: 10.1111/gcb.16814

Aboveground, large and higher trophic‐level organisms often respond more strongly to environmental changes than small and lower trophic‐level organisms. However, whether this trophic or size‐dependent sensitivity also applies to the most abundant animals, microscopic soil‐borne nematodes, remains largely unknown. Here, we sampled an altitudinal transect across the Tibetan Plateau and applied a community‐weighted mean (CWM) approach to test how differences in climatic and edaphic properties affect nematode CWM biomass at the level of community, trophic group and taxon mean biomass within trophic groups. We found that climatic and edaphic properties, particularly soil water‐related properties, positively affected nematode CWM biomass, with no overall impact of altitude on nematode CWM biomass. Higher trophic‐level omnivorous and predatory nematodes responded more strongly to climatic and edaphic properties, particularly to temperature, soil pH, and soil water content than lower trophic‐level bacterivorous and fungivorous nematodes. However, these differences were likely not (only) driven by size, as we did not observe significant interactions between climatic and edaphic properties and mean biomasses within trophic groups. Together, our research implies a stronger, size‐independent trophic sensitivity of higher trophic‐level nematodes compared with lower trophic‐level ones. Therefore, our findings provide new insights into the mechanisms underlying nematode body size structure in alpine grasslands and highlight that traits independent of size need to be found to explain increased sensitivity of higher trophic‐level nematodes to climatic and edaphic properties, which might affect soil functioning. Aboveground, large and higher trophic‐level organisms often respond more strongly to environmental changes than small and lower trophic‐level organisms. However, whether this trophic or size‐dependent sensitivity also applies to the most abundant animals: nematodes, remains largely unknown. We investigated nematode CWM biomass at the level of community, trophic group and taxon mean biomass within trophic groups along an altitudinal transect across the Tibetan Plateau. We found that nematode biomass changes along an elevational gradient depend on trophic groups rather than body size.