Abstract: In this study, the richness and abundance of birds in the breeding season (May and June) from 2016 to 2018 were surveyed in the western parts of Alxa-Ordos Biodiversity Center using line transect and fixed-radius point count. In total, 92 bird species belonging to 15 orders, 37 families were recorded, which include 35 residents, 39 summer migrants, 17 passing birds and one winter migrant. Seven species are listed in the list of national second-class protected wildlife, including Pernis ptilorhyncus, Falco tinnunculus, Falco subbuteo, Accipiter nisus, Buteo japonicus, Buteo hemilasius and Milvus migrans. The Shannon-Wiener index was the highest in farmland but the lowest in desert, so did the Pielou index and the Margalef index. The results show that the birds were mainly distributed in ecosystems of farmland and steppe, while seldom occurred in desert. The highest community similarity was found between desert and steppe, whereas the community similarity between forest and any other ecosystems in Helanshan was generally lower. Except wetland, bird communities showed high similarity in other habitats among different years. It was also found that, farmland plays a key role in the maintenance of bird diversity in desert regions, due to the high heterogeneity and the stable water supply. In contrast, smaller wetlands have limited functions in the same aspect as a result of the seasonal drought.

Key words: Alxa Desert, breeding birds, diversity, avifauna, line transect, fixed-radius point count