Investigation into the Relationship between Gut Microbiota of Cranes and Their Feeding Environment in the Yellow River Delta

The gut microbiota plays essential roles in host health and environmental adaptation, particularly for migratory birds within wetland ecosystems. This study examined the gut microbial communities of common cranes ( Grus grus ) and White Cranes( Grus leucogeranus ) in the Yellow River Delta using 16S rRNA sequencing of 24 fecal and foraging samples. Alpha diversity (ACE, Chao1, Shannon, Simpson) revealed significant inter-group differences, indicating environmental filtering effects. Beta diversity (PCoA) confirmed strong separation between foraging and fecal samples (PC1 = 25%). Dominant phyla included Proteobacteria (24.6–37.4%), Firmicutes (4.8–29.0%), and Actinobacteriota (12.4–23.3%), with genus-level biomarkers identified via LEfSe: Ligilactobacillus (12.1% in DYH), Cryobacterium (9.2% in DYB), and Rhodococcus (5.4% in DYH). SourceTracker indicated predominantly unknown microbial origins (> 70%), suggesting uncharacterized environmental reservoirs. Functional prediction highlighted group-specific metabolic adaptations, including elevated amino acid transport in DYH (9.8% vs. 7.1% in DYBT; P < 0.05) and conserved defense mechanisms (8.5% across groups). Our findings demonstrate that crane gut microbiota is shaped by synergistic host foraging behavior and wetland environmental factors. This study provides novel insights into host-microbe-environment interactions in migratory birds and suggests potential microbial indicators for monitoring wetland ecosystem health.