Comparative Study On Plant Diversity In Urban Parks Between Shanghai,China And Salzburg,Austria

Biodiversity is the preconditions and primary foundations for human well-being.Due to rapid urbanization and global changes,urban ecological environment problem and sustainable development have been gradually paid more attention.Urban biodiversity and its conservation have become the focus and hotspot in urban ecology.Urban park,the key component of urban green infrastructure,provides many ecosyetem services not only homing birds and insects in urban areas,but also satisfying urban habitants' various demands.It is the place where most urban habitants' activities concentrated,however,it was also disturbed by human activities.The green plants are the dominant species in urban parks,therefore,are vital to maintain urban ecosystem health and biodiversity protection in urban areas.However,it is still unclear that whether the urban parks have the function of biodiversity conservation,and how many plant species the urban park can support?and whether the composition of plant species in urban park is stable over time.In this thesis,quantitative analyses and field investigation were employed to explore the supporting capacity and the dynamic and stability of plant species of urban parks in Shanghai,China and Salzburg,Austria,based on comparative studies from two aspects of park area and park history,i.e.the year of construction,respectively.To do so,I firstly related the plant species richness to park area,and further compare the capability of plant species in park groups in terms of park size.Secondly,I analyzed the differences of plant diversity in park groups with different construction years.This study demonstrated that urban park has strong supporting capacity for plant diversity in urban areas.The main research results of study are as follows:1.In this study,66 plant communities in 15 parks in Shanghai were surveyed.A total of 467 vascular plants belonging to 310 genera of 110 families,among,219 woody plants and 248 herbaceous plants were recorded,accounting for 15.61%of the existing vascular plants in Shanghai.There are 171 species of vascular plants in the 16 plant communities in 6 urban parks in Salzburg,including 64 woody plants,107 herbs,accounting for 8.6%of the total plants in Salzburg.The results demonstrate that urban parks,as one of the principal habitats,play an important role in maintaining high level of plant biodiversity in urban areas.2.Park area was the main factor in affecting the supporting function of park to plant diversity.There was a significantly positive correlation between the species richness and the park size.The plant species richness increased logarithmically with the park area.However,the species richness decreased per unit area with the increasing of park area.This relationship was proved in both Shanghai and Salzburg.In addition,the species richness of native and herbaceous species in Shanghai were also positively and logarithmically correlated to the park area.While the species richness also decreased per unit area with the increasing of park area.However,there was no relationship between exotic plant species richness and park area,with no significantly differences of exotic plant species richness among different urban park groups.3.There were differences in species diversity of different park size level between the two cities.The species richness of the total plants and woody plants in Salzburg were lower than that in Shanghai,however,the species richness of herbaceous plants was higher than that of Shanghai at the corresponding park size level.In Shanghai,the species richness of the total plants,woody plants and herbaceous plants for park groups exhibited that small park groups<medium park groups<large park groups.While in Salzburg,the species richness of the total plants and herbaceous plants in park groups was ranked as small park groups<medium park groups<large park groups;woody plant species richness ranking for medium park groups<small park groups<large park groups.Shannon-Wiener diversity and Heip evenness index increased with the park size level in Shanghai.While,the lowest value of Shannon-Wiener diversity and Heip evenness in Salzburg were the medium park group.4.In general,the biotic heterogeneity of urban parks in Shanghai,indictive of ?diversity value is 0.3886,was smaller than that in Salzburg where the P diversity value is 0.4832.In the same urban area of both Shanghai and Salzburg,the ? diversity of different park groups was higher than the overall ? diversity of the region;the highest ? diversity occurred in small park groups indicating the greatest difference of plant composition;the lowest one was in the medium park groups,implying extremly similarity of their plant species composition.The rank was:medium park groups<small park groups<large park groups.5.When parks in Shanghai were categorized into four classes in terms of construction year,I found that the number of the total plants,woody plants,herbs,and perennial herbaceous plants in the old park built up before 1978 were higher than that in the newly constructed park after 1978.The number of native plants increases with the built-time(? park groups>? park groups>? park groups>? park groups);the number of exotic plants in the old park were higher than that in the new park.There was no regular change of Shannon diversity s over the built-time(? park groups>?park groups>? park groups>? park groups),Heip evnness was generally lower,with the new park were slightly higher than the old park.As a whole,the degree of biotic homogenization of the new park was more serious than the old one.6.The plant communities in both the old and the new parks in Shanghai did not yet reach a steady state,however the longer of park history,the greater the number of young saplings in the plant community,indicating the greater potential of the old park to plant diversity conservation.Furthermore,the park plant community in different size levels also did not reach a stable state in both Shanghai and Salzburg.