Biotic interactions shape invertebrate diversity on downed logs in forest ecosystems
摘要
Invertebrate communities on downed logs not only play crucial roles in shaping the decomposition process of these logs but also participate in key ecological processes such as energy flow and material circulation. Yet, overall patterns of community composition, succession, and quantitative drivers remain poorly understood. Using high-throughput sequencing, we investigated invertebrate diversity across five decay stages of Quercus aliena var. acuteserrata and Pinus tabuliformis. Partial least squares path modeling (PLS-PM) quantified biotic and abiotic effects. The results demonstrated that: (1) invertebrate diversity and evenness increased with decay, with dominance shifting from Coleoptera in early stages to more balanced communities later. (2) Log-dwelling communities were consistently distinct from soil communities, with > 70% dissimilarity in Q. aliena var. acuteserrata and > 80% in P. tabuliformis, and contained unique taxa such as Coleoptera and Diptera. (3) Community structure was influenced by log properties, with tree-specific effects: physical traits (density, moisture) were dominant in Q. aliena var. acuteserrata, whereas both chemical (P, N, Ca, Mg) and physical traits had moderate influence in P. tabuliformis. Across both species, the soil invertebrate community, as a biotic factor, more notably influenced the invertebrate communities on the downed logs than log properties. Our findings emphasize the ecological and management importance of downed logs as habitats that sustain unique invertebrate assemblages and regulate carbon turnover. Effective forest management should therefore integrate downed logs retention, considering both tree-specific decay pathways and soil–log linkages. These findings offer valuable insights into how invertebrates influence log decomposition and carbon release and provide a systematic basis for strategies to conserve invertebrate diversity in forest ecosystems.
Graphical abstract