Analysis of Multi-medium Microbial Communities in the Habitat of Recurvirostra avosetta on Shell Bar Islands

Direct studies of Pied Avocet (Recurvirostra avosetta) feces to assess ecological effects are often constrained by sample degradation and instability. To address this, this study innovatively employs a multi-medium composite analysis method involving water, aquatic plants, soil, and nest sediments to indirectly and stably elucidate the driving effects of Recurvirostra avosetta activities on microbial communities in shell ridge wetlands and their implications for habitat health assessment. Results indicate significant specificity in microbial communities across the four media, with only 12 shared ASVs. At the phylum level, Proteobacteria dominated, while distinct differentiation emerged at the genus level: soil uniquely harbored the nitrogen-cycling genus Fodinibius, nest sediments were enriched with unclassified_Balneolaceae (a salt-tolerant group), and water and aquatic plant media featured aquatic photosynthetic groups. Alpha diversity analysis revealed that aquatic plants exhibit significantly higher microbial richness and diversity than the other media, serving as the core carrier sustaining the ecological functions of habitat microorganisms. NMDS and PERMANOVA analyses of Beta diversity confirmed high similarity in community composition between soil and nest sediments, a pattern driven by the dual effects of avian fecal input and nest-building activities. Functional prediction further revealed significant enrichment of nitrate reduction and hydrocarbon degradation functions in nest sediments. Among these indicators, fluctuations in the abundance of Fodinibius in soil reflect both Recurvirostra avosetta activity intensity and soil nitrogen cycling status - excessively high levels may indicate local nitrogen accumulation imbalance, while excessively low levels suggest soil ecological function degradation. Abnormal fluctuations in unclassified_Balneolaceae within nest sediments indicate salinity disturbance or pollution risks, while the strength of nitrate reduction and hydrocarbon degradation functions directly reflects the habitat's capacity to purify fecal contaminants.