Airborne eDNA Reveals Resource-Based Assembly of Frugivorous Vertebrates.

Food availability is a fundamental driver of vertebrate spatial distributions, yet quantifying these relationships across taxonomic groups remains challenging in structurally complex ecosystems such as tropical rainforests. Understanding how resource heterogeneity shapes community structure is critical for advancing ecological theory and informing conservation strategies. We combined airborne environmental DNA (eDNA) sampling with ground-based fruit tree surveys in the Xishuangbanna tropical rainforest to test whether measurable animal genetic traces in the air reflect the fine-scale distribution of animals driven by fruit resources. Airborne eDNA sampling revealed a diverse vertebrate community, with 71 bird and 18 mammal species detected at high spatial resolution in tropical rainforests. By applying occupancy models to account for detection bias, we show that vertebrate occurrence patterns are significantly influenced by both the overall abundance of fruiting trees and, more importantly, the availability of small fruiting trees across locations. Our findings provide the first compelling airborne eDNA-based evidence that fine-scale fruit resource availability, particularly from small-fruited trees, contributes to the spatial distribution of vertebrates in tropical rainforests of Xishuangbanna, China. These spatial couplings between plants and animals highlight the value of airborne eDNA not only for biodiversity monitoring but also for testing trait-based ecological hypotheses (e.g., fruit size selection by frugivores) and advancing theory on community assembly in structurally complex ecosystems.