Abstract:
Yuanyang County is located in the priority area for biodiversity protection in Xishuangbanna. However, there is a lack of information and related research on bird background in this area. Here, we investigated the bird diversity and vertical distribution patterns in Yuanyang County using the transect method from July 2019 to April 2020. To analyze the vertical distribution patterns of birds in this region, 44 transects were established based on altitude (144-2 936.9 m) and habitat characteristics. The investigation area was divided into 6 vertical zones with an altitude gradient of 400 m. A total of 179 bird species were recorded, belonging to 13 orders and 46 families, of these, 140 were resident birds (78.21%), 16 were summer migratory birds (8.84%), and 23 were winter migratory birds and travelers (12.85%). In the county, there are 24 species of national second-class protected birds 11 species of endangered (NT) and 1 species of vulnerable (VU) in the red list of vertebrates in China, and 1 endangered (NT) species in IUCN Red List. Among the seasonal changes, species richness (
n=115) and diversity index (
H=4.022) are the highest in spring, and species richness (
n=87) and diversity index (
H=3.666) are the lowest in winter. There is no significant difference in bird encounter rate between different seasons (
F=1.166,
P=0.328). The bird species richness is the highest at the altitude of 1 400-1 800 m, and the vertical distribution is in the middle peak mode. This follows a consistent pattern of variation with phylogenetic diversity while showing a different vertical distribution pattern from functional diversity. FRic (11.82), FDis (1.44) and PD (2 584.59) of breeding birds are the highest at the altitude of >1 800-2 200, 200-600 and >1 400-1 800 m respectively. SES.MFD of bird communities in >1 400-1 800 and >2 200-2 600 m altitude zones were significantly lower than the random values (SES <-1.96), indicating that the bird communities in these two altitude zones were functionally clustered. The SES.MPD of bird communities in >1 400-1 800, >1 800-2 200 and >2 200-2 600 m altitude zones were significantly lower than the random values (SES <-1.96), indicating that the bird communities in these three altitude zones were phylogenetically clustered, which may be related to the community construction driven by habitat filtration. The correlation analysis results suggest that environmental factors do not have significantly impact on avian species richness, functional richness, and phylogenetic diversity along the elevational gradients. This might be attributed to the combined effects of multiple factors. This study provides the background data of birds in Yuanyang County, which can provide reference for the protection and management of bird resources of the county.