Study On The Relationship Between Bird Diversity And Vegetation Characteristics In Uninhabited Islands Of Zhejiang Province

As a special marine ecosystem,the island has characteristics of both land and marine ecosystem.It is important to the development of marine economy,marine environment protection,ecological balance maintenance and national rights and interests defense in China.Uninhabited island is an important part of the ocean and are surrounded by abundant marine life,ports,oil and gas,minerals,ocean energy,wind energy and marine space resources.At the same time,some uninhabited islands or reefs on the border line are the base points of national territorial sea baselines.Therefore,the uninhabited island is not only of great marine economic significance,but also a symbol of safeguarding national marine rights and interests,such as the delimitation of sea area between countries.In order to investigate the effects of uninhabited island vegetation on bird diversity,the bird survey and vegetation survey were carried out in some islands of Wenling City,Zhejiang Province from 2017 to2018.Based on the relevant literature and field survey data,this study analyzed the relationship between island vegetation characteristics and bird diversity by means of statistical analysis,and provided scientific basis for the breadth and depth of island resources development.The main conclusions of this paper are as follows:(1)Based on the field investigation,the plant species in the study area were defined as 17 species of trees,68 species of shrubs and 138 species of herbs belonging to 166 genus and 223 species of 77 families.Among them,85 species belong to 35 families and 52 genus,138 species belong to 47 families and 106 genus,8 of 17 species belong to evergreen trees,9 species are deciduous trees,8 species belong to evergreen trees,9species belong to deciduous trees,8 species belong to evergreen trees,9 species belong to deciduous trees,and 138 species belong to 47 families and 106 genus.Among 68 species of shrubs,23 species are evergreen shrubs(including 5 species of evergreen climbing shrubs),45 species are deciduous shrubs(including 15 species of deciduous climbing shrubs),36 of 138 species of herbs are one,biennial herbs and102 species are perennial herbs.Among the 64 plots,the number of trees,shrubs and herbs was 17,accounting for 26.6% of the total.The number of samples in the sparse tree layer was 29,accounting for 45.3% of the total number of samples.Herbs are the most abundant species in the study area,followed by shrubs and trees,followed by shrubs,and the least tree species.The vertical structure of plants in the study area is complex and the habitat types are diverse.(2)Based on 4 field surveys in 2017 and 2018,49 species of birds were recorded.The total number of birds was 1454,belonging to 8 orders,27 families and 49 species.Among them,(Passeriformes)has the most species.Among the 49 species of birds,there are 3 species of national secondary protected animals,including(Falco subbuteo),white-bellied Harrier(Circus spilonotus)and(Centropus sinensis).According to the resident type,there are 20 resident birds in these 49 species,accounting for 40.5% of the total species.There were 13 species of winter migratory birds,26.5% of the total species,11 species of summer migratory birds,22.4% of the total species,and 5 species of traveling birds,accounting for 10.2% of the total species.Most of the birds in the study area are resident birds;the species of winter migratory birds and summer migratory birds are similar;the species of traveling birds are the least.There are 29 species of migratory birds,including 12 species of winter migratory birds,accounting for 24.48% of the total species of birds,11 species of summer migratory birds,22.44% of the total species of birds,and 4 species of traveling birds,accounting for 8.16% of the total species of birds.There are few aquatic birds in the study area,and the reasons are as follows: on the one hand,the investigated islands are bedrock coasts,and there is no big side.The accumulated beach is not suitable for the habitat of migratory birds such as shorebirds,geese and ducks.On the other hand,Hangzhou Bay and Changjiang Estuary wetlands,which have vast beaches and little human interference to the north,can provide enough habitat for foraging and rest because of the Yellow Sea and Bohai Sea,Changjiang Estuary and Hangzhou coastal beach wetlands.There is no need to stop living on the isolated island of Wenling along the southeast coast of Zhejiang Province.(3)there were significant differences in bird diversity in each habitats: more in mixed evergreen-deciduous broad-leaved forest and evergreen broad-leaved forest,lower in evergreen coniferous forest and grass bush,the reason was that the difference of tree age in the former habitat was quite large,and there was no significant difference in bird diversity between evergreen coniferous forest and grass bush,butnot in evergreen-deciduous broad-leaved forest.The vertical structure is complex and the shrub layer and herb layer are developed,which provide rich food,good shelter and suitable nest site for birds.There are significant differences in the number of bird species and the total number of individuals in different habitats,but the change trends of the two are similar.The more species there are in the habitat,the more corresponding individuals there are.As for different uninhabited islands,the diversity of island birds is closely related to the fragmentation,creeping and diversity of island habitat types.