Study On Evaluation And Optimal Disposition About Ecological Plant Community Of Urban Parks In Hefei

Plant community is a significant factor of urban parks, the reasonableness and stability of its structure are important to the ecological functions of green space. Ecological plant community refers to plant communities with rich species diversity, stable structure, good ecological benefit and meeting the recreational function, making higher quality requirements for plant community. Hefei, which is the earliest garden city in china, with good foundation, and has been committed to striving for national "eco-garden city" and therefore, the construction of ecological plant communities has important practical significance in Hefei.This research chooses 9 urban parks, including 43 typical plant communities as the studying object, to investigate the species composition, biodiversity, community structure and ecological function, taking notes of this information with investigational forms, ichnographies, photos and so on. Based on the investigation, this research makes efforts to build a comprehensive ecological evaluation system from the four aspects, species composition, community structure, ecological function, and scenic beauty. And then, this system is used to evaluate the 43 typical plant communities with five ranks. Based on the plant communities with higher score, the configuration mode of ecological plant communities were build for Hefei urban parks. The results show that:1. In the 43 plant communities to be surveyed, there are 115 species, which belong to 90 generas and 53 families. The species with frequency≥10% are high-frequency species. The top 10 high-frequency species of tree layer are Osmanthus fragrans,Cedrus deodara,Cinnamomum camphora,Magnolia grandiflora,Sapium sebiferum,Trachycarpus fortunei,Lagerstroemia indica,Platycladus orientalis,Sabina chinensis var. chinensis cv. Kaizuca,Salix babylonica, in which Osmanthus fragrans and Cedrus deodara's applications up to 30 %; Rhododendron amesiae,Pittosporum tobira,Loropetalum chinense var. rubrum,Nandina domestica in shrub layer ; Poa annua,Ophiopogon japonicus,Oxalis corymbosa,Zoysia japonica,Zephyranthes candida in ground cover. Diversity index order: tree layer> herb layer> shrub layer.2.? The correlation between vegetation quantity of 43 communities and plant Communities'Structural Characteristics, including the average tree height, average DBH, stand density, Simpson index, Shannon-winner index, Pielou index, species richness, shows that the average DBH is significantly positive correlated with vegetation quantity, the average height was positive correlated with vegetation quantity; in the calculation of the stability index of the nine indicators, the average DBH's weight is the largest, In the distribution of stability index, there are 4 grades in stronger, strong, medium and poor, plant communities with stronger and strong stability accounted for 51% of plots.3. Total 15 indicators selecting from species diversity, community structure, ecological function and landscape recreation were used to build the comprehensive evaluation system of ecological plant communities in Hefei. Of which the ecological function's weight is the largest, followed by community structure, species diversity, landscape recreation. Based on the evaluation scores, plant communities were divided intoⅠ,Ⅱ,Ⅲ,Ⅳ,Ⅴfive ranks. The number of classⅠcommunities accounted for 17% of plots.4. According to the ecological plant communities in comprehensive evaluation system, classⅠcommunities already have good ecological and landscape benefits and can be used as a reference system to build plant configuration models of ecological plant communities in Hefei. Based on the four different community types in research plots, the common configuration model were used to construct the specific configuration mode for broad-leaved and coniferous mixed forest, evergreen and deciduous broad-leaved mixed forest, deciduous forest and bamboo forest.