The Influence Of "City-Suburb" Gradient On Different Green Space Community Characteristics In Shenyang

With the development of urbanization,the complete urban ecological environment has been destroyed.Plants,as an important part of the ecological environment,have seen the decline of native tree species and plant diversity.Therefore,the protection of the urban ecological environment is particularly important.In this paper,Shenyang City is divided into four types of green spaces on a continuous gradient zone according to the geographical location of "urban-suburban-suburban" gradient,and analyzes the characteristics of plant families,genera,life forms,diversity changes and nutrients.To explore the impact of urbanization on plants.Provide reasonable suggestions for plant construction design and diversity conservation in Shenyang.The main results are as follows:(1)In the study area,there are 127 species of plants belonging to 45 families and 100 genera.The families with abundant plant species in the transect include Rosaceae(14 genera and 15 species),Gramineae(12 genera and 12 species),Leguminosae sp.(6 genera and 8species),Ulmaceae Mirb(3 genera and 6 species).The above-mentioned plant families account for 11.3% of the total number of families,and the genera account for 35% of the total number of genera.Accounted for 32.3% of the total number of species,the above-mentioned families and genera occupy a dominant position in the survey area.(2)Through the analysis of the composition of plant species in Shenyang,it can be seen that along the urbanization gradient,the number of plant species in Shenyang gradually decreases from the city to the suburbs,indicating that the urbanization process affects the number of plant species.Park green space> residential area green space> unit green space>street green space.In the study area,the herb life form ratio is 0.35,of which 13 are annual,most of which are in the study area.A total of 127 plant species are investigated,including 52 trees,25 shrubs,and 50 herbs.The ratio between them is 1: 0.48: 0.96.The life form ratio of arbor plants is 0.3,of which 40 species are deciduous.There are 12 evergreen species,and the life form ratio of shrubs is 0.32,including 19 species of deciduous shrubs,6 species of evergreen shrubs,and 37 species per year.The ratio of evergreen trees to deciduous trees is in the order of park green space,unit green space,street green space,and residential area green space;the ratio of evergreen shrubs to deciduous shrubs is in order of park green space,unit green space,street green space,and residential area green space;annual herb and The ratio of perennial herbs is in the order of park green space,street green space,residential green space,and unit green space.(3)The indexes of trees and shrubs in Shenyang City generally show a downward trend with urbanization,and herbs generally show an upward trend.The indicators of trees,shrubs and grasses in different types of green spaces have different trends,and the park green space is affected by urbanization.The most significant.Except for the more abundant shrub species in the suburbs than in Shenyang as a whole,the arbor,shrub and grass indexes under the othergradients are similar to the overall average trend of Shenyang,with obvious characteristics of urbanization.The trend of the overall tree plants in Shenyang decreases from the urban center to the suburbs.The green arbor in the residential area is more abundant in the suburban gradient.For unit green space and street green space,only herbaceous index trends are similar to those of Shenyang's plants on the urbanization gradient.Street green space is less affected by urbanization,indicating that park green space is most affected in the process of urbanization,so Shenyang City Under the gradient of "urban-suburb",different types of green space are affected from high to low: park green space> residential area green space> unit green space> street green space.(4)The N/P of green land soil has a rising trend under the gradient of "urban-suburban-suburban" in Shenyang,and the C/N,C/P of green land soil and the gradient of "urban-suburban-suburb" increased first and then decreased the trend of.The rapid urbanization process has led to the spatial differentiation of the stoichiometric ratio of carbon,nitrogen and phosphorus.The carbon value of plant leaves increases along the urbanization gradient,and the nitrogen and phosphorus values ??are not greatly affected by urbanization changes.It shows that the stoichiometric characteristics of plant leaves are not directly determined by the soil nutrient content,but are more affected by the plant's own characteristics and are jointly determined by many factors.