Scale Effects On Parks And Their Plant Diversities Of Different Cities In Hebei Province

Park,as a social public service resource,is a place for residents to view and admire,have a rest and carry out outdoor activities.Park plants help to maintain the ecological balance of the city.Taking the parks built in 47 municipal district and 20 county-level cities in Heibei province as the research object,the number,the area and the plant species of the park system are investigated and analyzed.The current situation of the city park in Heibei province is revealed.Typical vegetation survey method is employed to investigate the plant diversity of city parks in Heibei province.Multiple characteristics and influencing factors for urban park of different scales cities are studied.Plant diversity and the influencing factors are discussed.This paper analyzes the distribution characteristics and plant diversity of urban parks of different scales,and discusses the influence of urban scale on the area,quantity and plant species diversity of urban parks.The results are as follows.In all municipal districts and county-level cities built up areas in Hebei Province,a total of 435 parks with clear green space characteristics are identified.The covering area is about 4778.126 hectares.317 parks of them are distributed in municipal districts,covering an area of 3942.078 hectares.And 118 parks are distributed in county-level cities,covering an area of 836.048 hectares.The total number of parks built in most municipal districts and county-level cities are less than 10 separately.And the total area of the parks in municipal districts and county-level cities are usually less than 100 hectares and 50 hectares separately.Among them,the total number of parks in Chengde City is the least.The total area of parks in Chengde City is the smallest,too.The total number of parks in Shijiazhuang City is the most.And the total area of parks in Tangshan City is the largest.Viewing from the size of the parks of the different cities,Langfang,Handan,Baoding,Qinhuangdao,Cangzhou are close to each other.Chengde and Zhangjiakou are similar.Hengshui and Xingtai are similar with each other.Tangshan and Shijiazhuang have larger scale of parks than other cities.Through analyzing the impact of urban scale on urban parks,the results show that the number of parks has positive correlationship with the built-up area,the number of urban population,the value of the secondary industry and the value of the tertiary industry of the cities.The total parks area has positive correlationship with the built-up area,the number of urban population,the GDP and the value of the tertiary industry of the cities.It shows that the expansion of the city,the growth of the population,the development of the comprehensive economic strength and the development of the service industry promote the increase of the number of parks and the expansion of the park in the built-up area in diverse cities of Hebei province.The larger the built-up area is,the fewer the number of parks and the higher the proportion of the parks area relatively are.The greater the number of urban population is,the fewer the number of parks and the smaller the park area relatively are.Through the PCA analysis of the influencing factors on park number in each city,the results show that the numbers of park has a greater correlation with the built-up area,urban population and the development of the tertiary industry,but less with the development of the comprehensive economy,the primary industry,the secondary industry and industry.Compared to the city economic indexes: GDP,primary industry value,secondary industry value and industrial value,the area of parks is more correlated with urban built-up area,urban population and tertiary industry value.Using typical investigation method,the vegetation in 66 parks is investigated.93 arbor species,61 shrub species and 164 herbaceous species are recorded.The statistical results show that the commonly cultivated arbors in urban parks of Hebei province are:Sophora japonica Linn.,Koelreuteria paniculata Laxm.and Pinus tabuliformis Carr.;etc.The preferred planting shrubs are Amygdalus triloba(Lindl.)Ricker,Euonymus japonicus Thunb.and Hibiscus syriacus Linn.;etc.Widely used green herbs are Setaria viridis(L.)Beauv.,Eleusine indica(L.)Gaertn.and Hemerocallis fulva(L.)L.;etc.The diversity of plant communities in urban parks from high to low is as follows: Xingtai,Handan,Langfang,Tangshan,Cangzhou,Baoding,Qinhuangdao,Shijiazhuang,Hengshui,Zhangjiakou and Chengde.The evenness of plant community in Chengde city park is the lowest and Xingtai city is the highest.The results of the correlationship between plant diversity and city economy,population,climate and other factors show that the greater the gross urban product is,the more arbor,shrub,herb and plant community species in city parks are.The higher the secondary industry value is,the more arbor and plant community species in city parks are;The higher the tertiary industry value is,the more arbor,shrub and plant community species are in city parks.The larger the total industrial value of the city is,the greater the numbers of arbor and plant community species in the city park are.The more urban population is,the more arbor and shrub species in urban parks are.The larger the urban built-up area is,the more herb species are found in the park and the greater the overall richness of the park plant community is.The more parks in urban built-up areas are,the more arbor and shrub in urban parks are.The higher the annual mean temperature in the city is,the higher the diversity and evenness of the arbor in the urban parks are.But the annual mean precipitation has no obvious effect on the park plants.Through the PCA analysis of the influencing factors on the plant diversity of arbor,shrub and herb in each city park,results are found that: in the arbor layer,species richness and Shannon Wiener diversity index have a great correlationship with primary industry value,secondary industry value and industrial value of the city.Simpson diversity index and Pielou evenness index are greatly affected by built-up area,park area,the number of parks and the number of urban population of the city.In the shrub layer,species richness is significantly correlated with the number of urban population,the number of parks and the area of parks,while species diversity and evenness have little correlation with the social and climatic factors.In the herb layer,species richness,diversity index and Pielou evenness index are significantly correlated with the area of parks,the number of parks,the built-up area,the number of urban population and the annual average precipitation of the city,but less correlated with the economic level and annual average temperature of the city.For park plant community,there is a significant correlationship between plant species richness,Simpson diversity index and built-up area,park area,park number,urban population and annual average precipitation,seperately.Pielou evenness index is significantly affected by economic indexes: GDP,primary industry value,secondary industry value,tertiary industry value,industrial value and annual mean temperature.The results of this study can provide a reliable theoretical basis for the study of the development law and maintenance mechanism of urban parks in Hebei Province.It can also contribute to the future planning of city park and the protection and utilization of urban plant diversity in Hebei Province.