Wild Vascular Plants Diversity On Islands,Dalian

The ecosystem of oceanic islands is independent to mainland due to the segregation between them.Study on plant diversities on oceanic islands is significantly helpful to explore the origin of islands,the evolution of islands,the seed dispersal and biological diversity protection.In our research,an investigation of wild vascular plants diversity was conducted on typical islands in Dalian,and then their plant diversities are analyzed.The main results are as follow:(1)The level of plant diversity on oceanic islands in Dalian is relatively high to other islands in the north of China.There is a complicated composition of species as well as a scattered composition of genera on account of many single species families and single species genera.588 wild vascular plants were recorded belonged to 324 genera and 92 families.Angiosperms are predominant while the amount of gymnosperms is the least.(2)The composition of the flora on oceanic islands in Dalian is complex.The flora is composed of a large part of temperate elements and also accounts for certain tropical elements,Old World Temperate elements and East Asia elements.In addition,the element of Endemic to China is relatively rich to other areas.(3)50 endemic plants were found on oceanic islands of Dalian,which are worth research and protecting,including Pteroceltis tatarinowii,Chionanthus retusus,Koelreuteria paniculata,etc.(4)From the plant similarities research,the composition of the flora on the whole research area is more similar to the land in Dalian than to Changdao.Interior-similarities between each of these islands are low.Meanwhile similarities coefficients between nearby islands are related to the area,the distance from the shore,the effect of bird pollination and the degree of artificial disturbance.(5)The speciation-area relationship of oceanic islands in Dalian accords with the theory of island biogeography reported by Mac Arthur RH and E.O.Wilson,but it is also affected by artificial disturbance.