Land-use change has host-specific influences on avian gut microbiomes.

Human modification of the environment, particularly through land-use change, often reduces animal species diversity. However, the effect of land-use change on the gut microbiome of wildlife in human-dominated landscapes is not well understood despite its potential consequences for host health. We sought to quantify the effect of land-use change on wild bird gut microbiomes in a countryside landscape in Costa Rica, comprising a range of habitat types, ranging from primary and secondary forests to diversified and monoculture farms. We collected 280 fresh fecal samples from individuals belonging to six common species of saltator, thrushes, and warblers at 24 sites across this land-use gradient. Through 16S rRNA community profiling, we found that bacterial species composition responded to host species identity more strongly than to habitat type. In addition, we found evidence that habitat type affected microbial composition only for two of the six bird species. Our findings indicate that some host species and their microbiota may be more vulnerable to human disturbances than others.