Molecular diet analysis of common cranes (Grus grus) under supplementary feeding based on fecal DNA metabarcoding

Abstract

AbstractThe migratory and omnivorous common crane (Grus grus) uses a nature reserve with crucial ecological value that provides supplementary food resources, although the extent of their use by these cranes is unknown. In this study, we used DNA metabarcoding of plants through the chloroplast rbcL gene to investigate the diets of 25 common crane fecal samples and performed analyses in conjunction with supplementary feeding. The results showed that common cranes preferred plants of the families Poaceae and Cyperaceae, similar to common cranes in other nature reserves. Before supplementary feeding, Poaceae and Cyperaceae accounted for 43.83 ± 20.58% and 53.51 ± 19.24%, respectively, while after that, they accounted for 61.23 ± 35.19% and 24.07 ± 28.20%, respectively. The relative abundance of Hordeum increased significantly in January, accounting for 33.88 ± 31.32%, which was mainly affected by supplementary feeding. Therefore, under supplementary feeding, foraging grounds and feeding preferences of common cranes may change correspondingly. The quantity of corn kernels and wheat grains can be increased appropriately in supplementary feeding measures in the nature reserve, and more supplementary feeding sites should be set up in response to the shortage of wild bird food resources. This study applied an effective method to study the diet preference of common cranes under supplementary feeding and further provided insights to improve management measures in the nature reserve.