Study On The Plant Landscape Of Country Parks In Beijing

Along with the propulsion of the urbanization progress, urbanization brings people material abundance and enjoyment, however, all these benefits brought by urbanization are at the expense of damaging the natural landscape of suburbs, which is act as the ecological barrier of the city and takes unprecedented environmental pressure to people. Country Park, as a new type of green space mode, has important role in protecting urban and rural natural ecological environment, maintaining integrity of ecosystem, enriching residents’ leisure life and promoting urban and rural construction. In 2007, Beijing carried out a "Country parks ring" building project of urban isolated afforestation region. By the end of 2012, a total of 48 new country parks were opened, what means the "country parks ring" of Beijing has been mainly builded up. This study takes the 48 country parks as the research object. Firstly, the sampling survey method wsa used to investigate the species composition, the species origin, the invasive species, the dominant species, the family and genus level, the community structure, the species richness, the species diversity and the species evenness of plants in these 48 parks, revealing the quantitative characteristics and diversity characteristics of country parks in Beijing. Secondly, on the basis of the field investigation, the method of Analytic Hierarchy process (AHP) was used to build the plant landscape composite evaluation system of country parks from the landscape, ecological, practical three sides. After that, the composite evaluation and classification were accomplished to these parks. Finally, according to the results of the investigation and evaluation, the main points on plant landscape construction and construction of country park were summarized, and then an optimization strategy was proposed, which is directed against to the deficiencies and problems of country parks in Beijing, hope to provide a reference for the plant landscape renovation and construction of country parks. The main results were as follows:(1) A total of 651 plant species were counted, which belong to 107 families and 374 genera. Among these 651 species, there were 127 species of arbor, belonging to 30 families and 56 genera; 118 species of bushes, belonging to 30 families and 62 genera; 388 species of herbage, belonging to 66 families and 253 genera; 15 species of liana, belonging to 10 families and 13 genera; and 3 species of bamboos, belonging to 1 families and 2 genera.(2) The families and genera of country parks in Beijing obviously showed a level of large, medium and small, with the dominant families and genera having a prominent advantage position in the composition of plants. The top five dominant families were Rosaceae, Compositae, Gramineae, Leguminosae, and Salicaceae, up to 38.25% of total plant species (249 species). The top three dominant genera of the cultivated plants were Prunus, Salix and Populus. The top three dominant genera of the volunteer plants were Polygonum, Amaranthus, and Viola.(3) The amount of native plants species in Beijing country parks was 440, accounting for 67.59% of the total plants species,and the amount of alien plants species was 211, accounting for 32.41% of the total plants species. The proportion of native plants in different life forms were:arbor (74.80%)> herbage (67.78%)> bushes (61.02%).29.38% of the alien plants were domestic alien plants, and the rest 70.62% were exotic alien plants. Besides,44 species belong to 18 families and 35 genera were invasive species, accounting for 6.76% of the total plants species. The primary families of invasive plants were Compositae (11 species), Amaranthaceae (7 species), Gramineae (6 species), and Legumes (4 species).(4) At species level, the proportion of arbor, shrubs and herbage is 1:0.93:3.06, the ratio between evergreen and deciduous at arbor layer is 1:5.68; and at shrub layer is 1:8.08; at herbag layer, the ratio between annual or biennial plants and perennial plants is 1:1.43. Among the 1375 sampling points,459 phytobiocoenoses (33.38%) were arbor-shrub-herbage complex communities,426 phytobiocoenoses (30.98%) were arbor-herbage communities,178 phytobiocoenoses (12.95%) were arbor communities, 143 phytobiocoenoses (10.40%) were arbor-shrub communities, and the rest 169 (12.29%) phytobiocoenoses belong to the other types (except the four above). The phytobiocoenose characteristic of country parks in Beijing were mainly arbor-shrub-herbage complex types, arbor-herbage types, arbor types, and arbor-shrub types.(5) At the biodiversity of plants, Patrick index, Simpson index, Pielou index showed that herbage (4.155,0.642,0.830)> arbor (2.763,0.468,0.723)> shrub (1.268,0.199,0.339). In general, the plant diversity of country parks in Beijing is not high.(6) Based on the analytic hierarchy process, the composite evaluation system on the plant landscape of country parks in Beijing was established. In this system,29 composite evaluation index from landscape level, ecological level and utility level were set as evaluation criteria. After that the composite evaluationon the plant landscape of country parks in Beijing was accomplished. The results showed that the level of I included 4 country parks, accounting for 8.33% of the sum that were evaluated; the level of II included 16 country parks, accounting for 33.33% of the sum that were evaluated; the level of III included 23 country parks, accounting for 47.92% of the sum that were evaluated; only 16 country parks belong to the level of IV, accounting for 10.42% of the sum that were evaluated.The score of composite evaluation on the plant landscape of country parks in Beijing was 2.888 (The five-grade marking system), and the composite evaluation index was 57.76%. According to the grading standards of the plant landscape composite evaluation index,the the plant landscape level of country parks in Beijing was at level III, the medium level.(7) Based on the composite evaluation and the investigation on the plant landscape of country parks in Beijing, the main points on plant landscape construction and construction of country park were summarized from the landscape level, the ecology level, and the practicability level. In addition,6 optimization strategies were proposed to solve the deficiencies and problems in the plant landscape construction of country parks. And 60 kinds of arbor,60 kinds of shrubs, and 112 kinds of herbage were recommend, which were suitable for promotion in the plant landscape construction country parks in Beijing. Then, in view of the further optimization of the plant landscape composite evaluation high score sampling points, several plant configuration modes for different function division of country parks were recommend.The study focused on the current construction hotspot, and based on the theoretical researches and methods of multiple disciplines to research and explore the plant landscape of country parks in Beijing. Through the study, experiences were condensed from the practice, and then will be applied to the practice, in order to improve and perfect the theoretical system of country park construction in our country.