Noninvasive sampling for comparisons of wildlife microbiomes may be more reliable than sampling trapped animals

In ecological and conservation studies, responsible researchers strive to obtain rich data while minimizing disturbance to wildlife and ecosystems. We assessed if samples collected noninvasively can be used for microbiome research, comparing microbiota of noninvasively collected fecal samples to those collected from trapped common cranes at the same sites over the same periods. We found significant differences in microbial composition (alpha and beta diversity), which were not accounted for by noninvasive samples’ exposure to soil contaminants, as manually assessed by comparing differentially abundant taxa. They could result from trapped birds’ exposure to sedatives. We conclude that if all samples are collected in the same manner, comparative analyses are valid, and noninvasive sampling may better represent host microbiota because there are no trapping effects. Experiments with fresh and delayed sample collection can elucidate effects of environmental exposures on microbiota. Further, stressing or sedation may unravel how trapping affects wildlife microbiota.