Number and nest-site selection of breeding black-necked cranes over the past 40 years in the Longbao Wetland Nature Reserve, Qinghai, China

摘要

Black-necked crane (Grus nigricollis , BNC), facing serious threats from human activities and habitat variations, is an endangered species classified as vulnerable under the revised IUCN Red List. In this article, we investigated and analyzed the population and nesting microhabitat of BNCs in the Longbao National Nature Reserve (NNR) from 1978 to 2016, and found the number of BNCs increased from 24 in 1978 to 216 in 2016. This establishment of the Longbao NNR represented the activities of protecting endangered animal species are effective. However, the land cover classification results of Landsat images showed that the marsh wetland, which was the BNC’s primary habitat, decreased during 1978–2016, while artificial buildings increased, which affected the habitat of BNCs. The increase in average temperature over the past 40?years has also had an impact on the number of BNCs. BNCs preferred to nest in marsh wetlands or on islands with open water or star-like distributions through observation. The results of the principal component analysis showed that the nearest distance between nests and habitat type were the primary factors influencing nesting site selection. To protect BNC, we suggest decreasing wetland fragmentation, reducing habitat degradation and providing an undisturbed habitat.