Birds Fauna,Abundance And Vertical Distribution Pattern And Vertical Migration In Warm And Cold Season In Lebu Valley,Eastern Himalaya

Lebu valley located at the southern wing of the eastern Himalayas.The species richness and space pattern changes of the birds in warm and cold seasons were studied on the elevation gradient of Lebu valley.In this way,It help us to understand the birds species diversity and geographical pattern in this region very well,and atract more attention and understanding of biological hotspots,and provide scientific basis for biodiversity conservation in this region.This study conducted total three times surveys on bird species diversity,first time was in the warm season of 2018,and the second and third time was the warm season of 2019 and the cold season of 2019,using the line method from the altitude of 2300 m to 5000 m in Lebu valley.The study covers the main and lateral valley of the whole Lebu valley.The results were showed as follows:(1)A total of 5,871 birds were recorded in the three surveys,including 152 species belonging to 10 orders,33 families and 89 genera,accounting for 32.1% of the 473 known bird species in Tibet autonomous region.The bird community was mainly composed of passerine birds,with 128 species belonging to 24 families,69 genera,accounting for 84.2% of the bird species which surveyed.(2)In terms of residence type,resident birds were the main species,with a total of 103 species,38 species of summer migratory birds,6 species of winter migratory birds and 5 species of traveling birds.(3)There were 91 dominant species in the upper Oriental realm,47 species in the Palearctic realm and 14 widely distributed species in the fauna.(4)The vertical elevation distribution pattern of bird species diversity belongs to the former middle peak model in warm season of Lebu valley;The vertical distribution pattern of bird diversity belongs to the monotonic decreasing pattern in cold season.(5)The vertical elevation changes of bird fauna belongs to the mid-domain in the warm season of Lebu valley,and the Oriental realm and the Paleartic realm all belong to the mid-domain,and the intersection point of the two zoogeographical taxa appeared at the elevation belt from 4100-4700 m.In the cold season,the vertical elevation changes of bird fauna showed a monotonic decreasing in the Oriental realm,and that of the Oriental realm species showed a mid-domain,and the intersection point of the two zoogeographical taxa appeared at the 3500-3800 m elevation belt.(6)The species similarity analysis among the altitude belts in Lebu valley,it indicates that the similarity index between adjacent altitude belts is higher.There are significant differences in the species numbers and eco-types of the low-altitude belt and the high-altitude belt(7)Birds found in the cold and warm seasons in lebugou had higher distribution in the warm season and lower distribution in the cold season;The distribution range is narrow in warm season and wide in cold season.(8)The number of birds and species in the cold season in Lebu valley was higher than that in the warm season at the low altitude,while the number and species of birds in the warm season at the middle and high altitude were higher than that in the cold season,indicating that the birds had vertical migration to the ground elevation in the cold season.This is the first survey of birds in the cold and warm seasons of Lebu valley,which not only provides the basis for the ecological protection measures in the region,but also complements the data of the cold season survey of birds in the eastern Himalayas.