Birds Diversity And Mixed-Species Flocks Of Baiyun Lake National Wetland Park In Hunan Nanshan

Wetland,with rich biodiversity,is the transitional zone between land and water ecosystem,but is one of the most severely disturbed and damaged ecosystems in the world.From October 2017 to November 2018,we conducted a year-long research of the birds in Baiyun Lake National Wetland Park which is located in Chengbu Miao Nationality Autonomous County.We surveyed on bird species,quantity,community diversity and mixed-species flocks.The main results are as follows.(1)A total of 12,566 birds were recorded in this survey,belonging to 144 species of 42 orders and 42 families,including 87 species of resident birds,34 species of summer migratory birds,12 species of winter migratory birds,and 11 species of migratory birds.As to the faunal geographic distribution,76 species belonged to Oriental realm,21 species belonged to Palaearctic realm,and 47 species belonged to Eurytopic realm.As to Protection level,19 species were listed in the national second-class protected animals,6 species were listed in the "China Endangered Red Book"(Aves),and 20 species in the Convention on International Trade in Endangered Species of Wild Fauna and Flora(CITES)appendices ?.(2)By calculating the G-F index of the study site and comparing it with the other four protected areas,it was found that the bird species diversity of the Baiyun Lake National Wetland Park is higher than that of the nearby Fanjingshan Nature Reserve.The Shannon-Wiener index,Pielou evenness index,Simpson dominance index and Margalef richness index were used to analyze the biodiversity of four selected habitats(broad-leaved forest,coniferous and broad-leaved mixed forest,wetland and farmland)during different seasons.Among the four seasons,the bird diversity index and richness index showed highest in autumn.Among the four habitats the bird diversity index of wetland habitat was the highest,while the bird richness index of coniferous and broad-leaved mixed forest was the highest.Sorenson similarity coefficient was used to analyze the similarity of bird communities in four habitats,showing that the bird community of coniferous and broad-leaved mixed forest and broad-leaved forest had the highest similarity.(3)A total of 169 mixed-species flocks with 5,689 birds were recorded in this survey,belonging to 44 species of 2 orders,15 families.Among them,3 species belonged to Ardeidae of Scorpionidae,while all the rest belonged to the Passeriformes.The average number of species per each mixed-species flock was 3.53,with an average population of 30.81 per each flock.Alcippe davidi,Pycnonotus jocosus and Parus major in the mixed-species flocks are classified as the nuclear species,while Pycnonotus sinensis,Spizixos semitorques,Aegithalos concinnus,etc are classified as the follower species.The nuclear and follower species can maintain the cohesion and stability of the mixed flock.(4)The structure of mixed-species flocks were different among the four habitats.The numbers of mixed-species flocks,of total bird species composing the mixed flocks,and the average number of species per each mixed flock showed the highest in coniferous and broad-leaved mixed forests.The average number of species and of birds for mixed-species flocks showed the least in the farmland habitat with single vegetation and most human disturbance.(5)Based on feeding behaviors of the mixed-species flocks,it is divided into four feeding-on groups,namely the ground and shrub group,the middle group,the middle and upper group and the forest canopy group.After comparing the widths of the comprehensive niche of the feeding behavior for each species in the mixed-species flocks,it was found that the comprehensive niche widths of Alcippe davidi,Pycnonotus jocosus and Parus major as nuclear species were larger,compared to those of follower species.After comparing the niche overlapping values of the nuclear species with those of the follower species,it was found that although the niches of nuclear species overlapped largely with that of some of the follower species,both categories can coexist stably.This also shows that the ecological condition of the Baiyun Lake National Wetland Park is good and can provide sufficient food resources for birds.