Seasonal Variation And Diversity Of Authigenic Plant Composition In Waterfront Green Space Of Yitong River In Changchun City

In recent years,with the progress of society and the rapid development of national economy,the research on landscaping in China is also developing in depth.People gradually realize that while beautifying the environment,there are a series of problems,such as excessive consumption of resources,landscape homogenization,reduction of biodiversity of urban green space and so on.Authigenic ground cover plants are favored by the majority of landscape architects because of their strong adaptability,rich species and low maintenance cost.Moreover,authigenic ground cover plants can reproduce by themselves,with low maintenance and management cost and good ecological benefits.They can better adapt to the urban green space ecosystem and enhance the local characteristics of urban landscaping,urban ecological restoration,wetland restoration It is of great significance to avoid the invasion of alien species and the application of sponge city.Urban wetland is an important part of urban natural environment.With its unique function,it can better enhance the potential of urban environmental regulation and protection,ensure the sustainable development of the city,and have a positive impact on the urban environment.Urban Wetland Park mainly refers to natural or artificial swamps.Urban Wetland Park has the functions of maintaining the balance of animals and plants in the ecosystem,purifying urban air,purifying water pollution and improving urban environmental quality.At the same time,the development and protection of wetland will provide better resources for urban tourism development and human residence.Therefore,the development and utilization of Wetland Park is of great significance to urban development.In this paper,the authigenic ground cover plants of waterfront green space on both banks of Yitong River in Changchun(Nanxi Wetland Park Changchun North Lake Wetland Park)are taken as the research object.Through the analysis of plant species composition,life form,source and diversity,the authigenic ground cover plants of urban wetland park with high utilization value are selected,and the application mode of authigenic ground cover plants in Changchun Wetland Park is discussed,In order to provide a basis for the garden application of authigenic plants.The results of this investigation and research show that there are 66 species of self growing ground cover plants in the waterfront green space on both sides of Yitong River,belonging to 29 families and 62 genera.It can be seen that the self growing ground cover plants in the waterfront green space on both sides of Yitong River in Changchun are rich,but there are problems of low utilization rate and inadequate protection measures.The specific results are as follows:1.There are 47 native ground cover plants in the waterfront green land of Yitong River in Changchun,accounting for 71.21%;There are 15 species of authigenic ground cover plants in other parts of China,accounting for 22.73%;There are four kinds of introduced or invaded native ground cover plants abroad,accounting for 6.06%,accounting for a small proportion.The results show that there are few species of exotic ground cover plants and their dominance is low.Compared with rural land cover plants,they are less distributed and less competitive.2.The analysis of the life form composition of authigenic ground cover plants in the waterfront green space of Yitong River in Changchun shows that the authigenic ground cover plants are composed of perennial grass local cover plants,annual or biennial herbaceous ground cover plants,annual grass local cover plants and vines.Among them,the proportion of perennial grass local cover plants is the highest,with 31 species,accounting for 46.97% of authigenic ground cover plants;There are 22 species of annual grass native cover plants,accounting for 33.33% of the native ground cover plants;There are 11 species of annual or biennial grass native cover plants,accounting for 16.67% of the native ground cover plants;There are only two species of vine,namely,asclepiadus japonica and Euphorbia,accounting for 3.03% of the self ground cover species.It can be seen that perennial herbs have high dominance and the most distribution.Annual grass and local cover plants have strong transmission ability and good self reproduction ability.3.In the species composition of authigenic ground cover plants in the waterfront green space of Yitong River in Changchun,the top five families with important values are Asteraceae,Fabaceae,Plantaginaceae,Gramineae and Chenopodiaceae,with important values of 20.20%,11.46%,9.67%,8.53% and 8.28% respectively.Among them,Compositae plants are the most abundant,with 14 genera and 17 species.Plantago,Chenopodium,Crepis,Conyza and Trifolium have higher importance values,which are 9.67%,7.88%,6.24%,5.60% and 5.14% respectively.The top five self growing ground cover plant species of waterfront green space on both banks of Yitong River are Plantago depressa,Chenopodium album,Crepis tectorum,Conyza canadensis and Trifolium repens,with important values of 9.67%,7.88%,6.42%,5.29% and 5.14%respectively.The survey data show that the distribution of these five plants is relatively uniform.The highest relative frequency of species is cheqian,which is 29.92%,followed by wugen grass,which is 25.10%.The above two species are native native plants,indicating that native native plants are more suitable for the local green space environment of Changchun City,have stronger vitality and more natural advantages than other plants.4.The growth environment of authigenic plants in the waterfront green space of Yitong River in Changchun can be divided into five types: waterfront green space,lower green space,middle green space,upper green space and municipal roadside green space.Among them,there are 16 families,34 genera and 34 species of ground cover plants in the waterfront type green space,17 families,35 genera and 35 species of ground cover plants in the lower type green space,24 families,49 genera and 52 species of ground cover plants in the middle type green space,27 families,50 genera and 55 species of ground cover plants in the upper type green space,and 18 families,33 genera and 35 species of ground cover plants in the municipal roadside type green space.The Simpson dominance index of each green space is ranked as upper green space(2.242)>middle green space(2.228)> lower green space(2.098)> waterfront green space(2.007)> municipal roadside green space(1.248).The geographical environment of municipal roadside green space is relatively poor,there are many roadside vehicles and serious pollution,so the dominance index is the lowest.Shannon Wiener diversity index and dominance index have the same trend,and the order is middle green space(1.200)>upper green space(1.128)> waterfront green space(1.044)> lower green space(1.014)> municipal roadside green space(0.850).The diversity index of green space in the middle section is the highest,which indicates that the biodiversity of green space in the middle section is high,with the most species of authigenic ground cover plants,suitable for plant growth,superior growth environment and good soil and water.The order of Margalef richness index is lower green space(0.704)> upper green space(0.699)> middle green space(0.672)> waterfront green space(0.627)> municipal roadside green space(0.597).The richness index of several green spaces is similar,and the difference of richness index is not significant.The order of Pielou evenness index is middle section green space(0.794)> upper section green space(0.746)> waterfront green space(0.725)> lower section green space(0.693)> municipal roadside green space(0.626).The evenness index of the middle green space and the upper green space is the highest,mainly because the vegetation in the middle green space and the upper green space often has regularity in order to beautify the environment,so the habitat is relatively single,while the plants in the waterfront green space are not disturbed,so there are many plant species.On the whole,the species content of authigenic ground cover plants in each green space type is relatively rich,and the species difference is small.Among them,the species of middle green space and downhill green space are relatively rich.5.The study on the diversity of authigenic ground cover plant species in the waterfront green space of Yitong River in Changchun under different seasons shows that the number of authigenic ground cover plant species in spring is 55 species in 49 genera and 28 families,the number of authigenic ground cover plant species in summer is 52 species in 49 genera and 23 families,and the number of authigenic ground cover plant species in autumn is 42 species in 40 genera and 19 families.There is little difference in the number of species in the three seasons,but the composition of species varies greatly.There are 31 species found in all three seasons.Through statistical analysis,it is found that the largest Simpson dominance index of green space species in each season is summer green space,with a value of 2.729;The minimum is green space in spring,with a value of 2.154.The maximum value of Shannon Wiener diversity index is 1.256,which is a green space in summer;The minimum value is 1.006,which is green space in autumn.The maximum of Margalef richness index is summer,with a value of 0.759;The minimum is spring,with a value of 0.669.The maximum value of Pielou evenness index is 0.780,which is a green space in summer;The minimum value is 0.659,which is the green space in autumn.On the whole,the dominance index,diversity index,richness index and evenness index of green space in summer are the highest,and the change trend of each index is roughly the same,which is mainly caused by the climate characteristics of Changchun.There are the most plant species and the best growth in summer,but many plants have declined in autumn.