Study On The Plant Landscape Of Urban Ecological Corridors In Beijing

In recent years, the rapid economic growth and urbanization have reduced the urban green space and increased its fragmentation. Urban ecological corridors, as the linear factor of urban forests, not only possesses the common ecological function of green space, but also plays a significant role in aspects as connecting urban and peripheral environment, linking urban green patches and promoting the exchanges between material and energy. The thesis chooses urban ecological corridors within the Sixth Ring Road of Beijing as the research object, including road ecological corridors and river ecological corridors. With random sampling survey, this thesis carries on a further research on the composition of plant species, relationships between vegetation and environmental factors and plant landscape features. Based on the results, it has provided principles for the planning of Beijing urban ecological corridors. Besides, it has also recommended the species of living suited plants and established the suitable models of plant community for the future promotion. The main conclusions from the investigation are as the following:(1) A total of287plant species (including mutation) belonging to199genera and72families are concerned. The existing plant species covered15geographic variant types and8geographic areas, mainly based on plants of three geographic area types as the north temperate zone, world-wide distribution and pantropical regions, which account for20%,15.5%and15%respectively. Road ecological corridors possess253plant species, which belong to178genera and68families and contain124local species and129alien species. The plant species in river ecological corridors can be classified into210types, subordinating to159genera and61families and covering116local species and94alien species.(2) With further distance from the center of the city, the total species and diversity of arbor and shrub plants and alien species present a declining tendency. In contrast to this, the total species and diversity of herbaceous plants hold a rising trend, while alien species keep slumping.(3) As for the urban ecological corridors (including road and river) within the Sixth Ring Road of Beijing, the diversity of herbaceous plants has kept growing while the diversity of arbors and shrubs has owned a decreasing tendency with the broadening of corridor’s width. Due to the declining of human disturbance, the diversity index of herbaceous plants has increased in positive correlation; whereas the diversity index of arbors and shrubs has dropped. Along with the improvement of light intensity, the diversity index of herbaceous plants has increased firstly and then fallen.(4) The analysis on plants landscape illustrates that there are171plant species in road ecological corridors within the Sixth Ring Road in Beijing and146in river ecological corridors, possessing obvious seasonal characteristics. The main seasonal aspects of urban ecological corridors are spring, summer and autumn, among which shrubs have a concentration on spring and summer while herbaceous plants and woody climber highly concentrate on summer and autumn respectively. The models of plant community in urban ecological corridors can be divided into2types: arbor-shrub-herbage and arbor-herbage, among which the road ecological corridors contain6subtypes and the river ecological corridors contain5subtypes.(5) On the planning level of plant species, the thesis puts forward four principles and provides151plant species for road ecological corridors and153plant species for river ecological corridors. Finally, the thesis establishes12typical models of plant community by citing examples. The study, based on field investigation, puts forward relevant improving proposals for plant species planning within the Sixth Ring Road of Beijing under the guidance of landscape architecture, ecology and aesthetics, which is also an attempt made on the basis of multidisciplinary field.