Study On Plant Diversity And Restoration Strategies Of Rural Small And Micro Wetlands In Gong’an County

Small and micro wetlands have the ecological functions of conserving rainwater,regulating rainwater and removing pollutants and excessive nutrients in surface water,and occupy an important position in the rural ecological environment.Based on the survey and statistics of vascular plants in 32 small and micro wetlands in Gong’an,Hubei province.We analyzed the species composition,specific distribution,plant diversity,vascular bundles and geographic distribution characteristics in small and micro wetlands in Gong’an County.Then used the germination experiment of seed banks to researched the species composition,quantity,scale composition,and the relationship between surface vegetation and underground soil.And classified 32 small and micro wetlands based on the degradation of surface plants;then analyzed the degradation causes of various types,and the relationship between species distribution and environmental factors,and evaluated some typical wetlands.These results will provide the protection and restoration strategies.The results showed that:(1)A total of 115 vascular plant species were recorded,belonging to 42 families and 84 genera.The main vegetation type was angiosperm.Gramineae and Cyperaceae were the dominant families with Alternanthera philoxeroides,Polygonum hydropiper,Setaria viridis,Zizania latifolia,Leersia hexandra,Eleusine indica,Leptochloa chinensis,Lemna minor,and Typha orientalis as dominant species.The species Margalef index was not high,and the development trend of diversity indices including Margalef index,Shannon-Wiener index,Simpson and Pielou index were basically identical.The life forms of surface vegetation were annual and perennial herbs,and most of the ecological adaptation types were wet plants.From the perspective of flora distribution type,the vegetation flora distribution type was rich,and widely connected with other flora of the country and the world,but the endemic genera were scarce in Gong’an County.(2)A total of 49 species of plants germinated,belonging to 13 families and 38 genera in 32 wetland soil seed banks.Plant life forms are mainly annual herbaceous plants,and ecological types are mainly wet plants;the dominant family were Gramineae and Cyperaceae,with Cyperus difformis,Leptochloa chinensis,Echinochloa caudata,and Fimbristylis aestivalis,Cyperus serotinus,Eleusine indica,Echinochloa crus-galli,Leersia hexandra,Cyperus michelianus,Kyllinga nemoralis,Sparganium stoloniferum as dominant species.The species similarities between surface vegetation and underground seed banks are low.Some germinated species disappeared from soil seed banks on the surface,while aquatic plants rarely appeared in soil seed banks.The 32 small and micro wetlands can be divided into 10 associations according to the Cluster analysis.Based on the environmental status of small and micro wetlands in the rural areas of Gong’an County,then selected slope protection method,land use methods,current functions,human disturbance intensity,water nutrition degree,and water bodies as the main indicators affecting the vegetation distribution of small and micro wetlands with the types and sources of disturbance.We used canonical correspondence analysis(CCA)and de-trend correspondence analysis(DCA)methods,to analyze the species distribution and current environmental factors.The results of RDA ranking analysis and the current investigation status indicated that the reasons for the degradation of small and micro wetlands in Gong’an County were divided into 5categories: 1)Wetland area reduction + habitat drought type;2)Breeding disturbance +agricultural pollution type;3)Heavy agricultural pollution type;4)Heavy breeding industry interference + man-made interference type;5)Domestic pollution discharge +agricultural pollution + strong man-made interference type.(4)First,based on the reasons for the degradation of small and micro wetlands,and provided the solutions to the external pollutants of small and micro wetlands from rural domestic sewage discharge,agricultural pollution,and pollution from the breeding industry.Then,we proposed restoration strategies for the restoration of small and micro wetlands in four categories: 1)Storage and stagnation small and micro wetlands,priority should be given to protecting the original wetland vegetation and improving its habitat according to the degradation status;2)Small and micro wetlands such as economic crop cultivation,which should be raised by humans,no Nelumbo nucifera and Zizania latifolia should be planted,and vegetation buffer zones should be established to alleviate the impact of agricultural production activities on the plant habitat and promote the natural restoration and development of vegetation;3)Fishery and poultry farming small and micro wetlands,should be gradually restored by diversion dilution,phytoremediation technology and seed bank restoration technology;4)Other comprehensive types of small and micro wetlands,with highest proportion.The biggest problem was to solve the interference caused by external pollutants from the source,eliminate or reduce the interference of human activities,and adopt ecological engineering to improve the habitat of wetland vegetation,and introduce native species to promote the reconstruction and transformation of natural wetland vegetation.Finally,this study puts forward the relevant enlightenment for the restoration of small and micro wetlands,and provides a theoretical basis for the restoration of rural small and micro wetlands in Gong’an County.