Distribution And Drivers Of Bird Species Richness And Community Structure In China

Biodiversity is characterized by a significant latitudinal and altitudinal gradient.It is widely acknowledged that biodiversity gradually decreases from low latitudes to high latitudes,and varies with elevation.This is not only the most important basic pattern of species distribution,but also the most common ecological pattern in nature.The geographical distribution pattern of biodiversity is determined by different temporal and spatial scale factors,such as regional geological history,glacialinterglacial climate change,contemporary climate,local biotic interactions and habitat heterogeneity.However,few studies have discussed the relative roles of these factors at the same time,especially from the aspects of species richness,phylogenetic structure and functional structure.In this study,distribution information of 1290 bird species in 214 prefecture level cities were collected from avifauna and zoology published in China,and 1130 breeding bird species were used to establish phylogenetic trees for phylogenetic structure analyses.Meanwhile,body size,feeding habits,residence types and habitat types were collected for functional structure analyses.Contemporary mean annual temperature,contemporary annual precipitation,contemporary-Last Glacial Maximum anomaly in MAT/MAP,plant species richness,and elevation range were used as environmental explanatory variables.The relationship between the distribution of breeding bird diversity and community structure and environmental factors is analyzed.The optimal combinations of environmental variables that can explain the current bird distribution pattern in China are proposed.And the direct and indirect effects of related environmental variables on bird species richness,phylogenetic structure and functional structure are evaluated.At the same time,this study also performed the same analyses on the bird data of various zoogeographical regions in China,and explored the consistency and differences of the bird diversity pattern among different zoogeographical regions through multiple comparisons.The main results are as follows:(1)The distribution pattern of bird diversity in our country has a significant spatial pattern.The southwest region has the most bird species.In addition,the phylogenetic and functional structure of the southwest region are relatively clustered,and the bird branch is relatively young.The phylogenetic ages of bird branches in Southeast China are higher than those in Southwest China.(2)Plant species diversity and palaeoclimate change were the direct factors affecting the geographical distribution of bird diversity in China,while elevation change could indirectly affect the geographical distribution of birds in China.Notably,more plant species and stable glacial interglacial climate may promote bird diversity through their effects on in situ diversification and species dispersal rate in southwestern China.(3)The results of the main driving factors of bird species richness in Northwest China,North China,Northeast China,Tibetan Plateau,South China and Southwest China are consistent with those of the whole country.The places with more plants and higher elevation gradient have more bird species.The richness of plant species in North China,Tibetan Plateau,Central China,South China and Southwest China is the main driving factor for the clustered of phylogenetic and functional structure of birds.Stable palaeo-temperature and abundant contemporary precipitation in Northwest,Northeast and Tibetan Plateau were the main driving factors for the clustered of phylogenetic and functional structure of birds.These findings indicate that more plant species and a stable glacial-interglacial climate may promote bird diversity by affecting the in situ diversification and species dispersal rate in Southwest China.Southeast China has the potential to be a museum of bird diversity,while southwest China has the potential to be a cradle of bird diversity.Therefore,the areas with higher plant diversity and more stable palaeoclimate have more bird species,and the protection of bird communities is of great significance for the conservation of biodiversity in China.