Diversity And Conservation Priority Of Wetland Vascular Plant In Yeyahu Nature Reserve, Beijing

Yeyahu Nature Reserve is the largest wetland nature reserve in Beijing, and has the most abundance biodiversity. The thesis studied thoroughly on flora, community classification, community framework and flora succession of it. Based on the sequences of priority protection of the wetland plants and habitat, some suggestions are put forward to management of Yeyahu. The investigation samplinged systemiclly and typically by transect lines. There were 11 sample sites, 104 transect lines and 562 quadrats which 161 belonged to hydrophyte, 245 hygrophyte, 140 halophyte and 16 hygromesophyte.After investigation and data analysis, it mainly contains 5 results. (1) There were 172 types of wetland vascular plants to be recorded. (2) There were 4 new species to be discovered: crypsis schoenoides, utricularia vulgaris, lindernia procumbens and inula salsoloides. And the appearance of Crypsis schoenoides is the outstanding performance of Yeyahu wetland soil salinization; utricularia vulgaris is aquatic insectivorous plant and the indicator plant of cleaning water. (3) The origin of the flora is very primordial. The genetic relationship has many ancient types and it is estranged. And most of the plant flora belong to temperate zone. (4) The monocotyledon has the highest importance value on the degree of families, genera and species。(5) The analysis divides the wetland vascular plants into 16 life form, and the one-year herb emerged plant are the most important ones.There were 4 vegetation type groups, 7 Vegetation Types and 58 formations to be classified. Form Phragmites australis dominates 13.88% of investigation areas. Such as Phragmites australis, Scirpus Planiculmis and Echinochloa caudata are the founder of wetland community physiognomy and structure.The analysis of vegetation framework included two results. (1) Species richness of wetland plant was low generally, and indices of plant diversity changed suddenly. It is obvious to be disturbed by road and other human activities. (2) Based on life-form and plant height, vertical distribution of community was divided into 5 levels. Twenty percent of investigation areas formed the typical aquatic vegetation zonal distribution; and remain of monolayer structure is an important signal that wetland environment was degradating.The research of vegetation succession indicated that the mesophyte is intruding into hygrophyte communities frequently. Increasing of halophyte and xeric plants revealed that ecosystem is changing from wetland to land.The study about the sequences of priority protection included two main results. (1) Evaluation system was established based on significance, rarity and usefulness. There were 42 plants to be evaluation and they should be rigidly protected in Yeyahu Nature Reserve. (2) Based on the research results of priority protected plants, plant diversity indices and the vertical structure of vegetation, there were 9 priority protection areas to be confirmed.According the results of research, there were several suggestion about emphases of protection work. (1) Rare aquatic plant should be protected to maintain diversity of hygrophyte in Beijing. (2) region of aquatic plant richness should be monitored to protect community diversity. And it could provide germplasm resources pool for the recovering of aquatic plant. (3) The function of aquatic plant to purify the water should be used thoroughly. And manual method such as fishing and removing should be use to promoted ecosystem health. (4) Ecological frangibility and function of improving soil environment of saline land vegetation should be regarded, and pioneer plants of saline land should be protected from trampling and grazing. (5) Typical wetland vegetation and insectivorous plants should be protected .rigidly.