Effects Of Fencing And Enclosure On Grassland Plant Community Characteristics And Diversity In Hongsongwa Nature Reserve

Grassland resources,as the largest area of land cover on the land area,as an renewable natural resources,is an important material basis for the survival and development of animal husbandry,with climate regulation,air purification,wind and sand,to maintain soil and water and tourism and other ecological Features.The Hongsongwa Nature Reserve is one of the best preserved natural grasslands in the north of China.Its geographical location is special.It is located in the northern section of Chengde agriculture and animal husbandry zone in Hebei Province.It protects the capital Beijing,Tianjin and northern China from the northern wind Ecological barrier function.In recent years,under the influence of climate change and over-grazing,indiscriminate digging,the grassland has gradually degenerated,the grassland ecological environment has deteriorated and the biodiversity is threatened.Therefore,the characteristics of grassland plant community and the diversity of grassland in the Hongsongwa Nature Reserve Sex,is of great significance.Fenced enclosure as a less investment and less effective restoration of degraded grassland measures,in the ecological environment protection and grassland monitoring has been widely used.Through the enclosure of the free-grazing grassland,it can not only increase the average height,coverage and above-ground biomass of the grassland plant community,but also improve the species diversity.Grassland enclosure,for the restoration and reconstruction of degraded grassland,grassland resources to achieve sustainable use,to maintain ecological security has an important role.In this paper,the grassland plant communities in the Hongsongwa Nature Reserve,Hebei Province,were used as the research object.The species composition,characteristics and other characteristics of the grassland plant community were obtained by field investigation and analysis of the enclosure in the study area in 2012-2016 for 5 consecutive years.The results showed that the original data were statistically processed,and the effects of enclosure on community composition were analyzed by comparing the proportion of plant species,genera and species in the fence inside and outside the fence.By comparing the characteristic values of the plant community inside and outside the fence,The ratio of biomass and its composition to different economic functional groups,and the variation of α diversity and β diversity,and the influence of enclosure on plant community quantity and biodiversity.The main conclusions are as follows:(1)After enclosuring for 5 years,the study area inside and outside the fence plant,genus,species composition ratio has changed,but not much difference.In 2012-2016,the proportion of the total number of species of the Compositae in the fence and the number of the total species is higher than that of the other sections,and the proportion of the miscellaneous plants is increasing year by year.The dominant species of the fence inside and outside the fence were not replaced by other species,and no obvious change was made,but with the increase of the enclosure period,the important value of the dominant species and other species inside and outside the fence changed.The important values of Polygonum cuspidatum,Phyllostachys pubescens and Artemisia sphaerocephala were increased,but the important value of the grasses of the miscellaneous grasses was reduced in the fence and increased outside the fence.(2)In 2012-2016,the average height,coverage and aboveground biomass of the vegetation inside and outside the fence increased year by year.The average height,coverage and aboveground biomass of the same fence in the same year of 2012-2016 were significantly higher than those of the fence(P<0.05).The average height,coverage and aboveground biomass of the grassland community were significantly increased by fence analysis.P<0.05).The average height,coverage and aboveground biomass of the plant were still increasing with the extension of the enclosure period(3)The enclosure biomass of the different economic functional groups of grassland plant communities inside and outside the fence of the study area changed to varying degrees.The aboveground biomass of the fine forage,medicinal and miscellaneous grasses in the fence increased to varying degrees,and the number of medicinal plants was decreased except for the fence.In terms of the ratio of aboveground biomass to the total biomass of the different economic functional groups,the change of the "two increasing and one drop" inside and outside the fence shows that the proportion of medicinal plants in the fence is increasing,The proportion of grasses decreased;the proportion of fine grasses and miscellaneous grasses increased,and the proportion of medicinal plants decreased.(4)With the enclosure time prolonged,the diversity of plant α increased,the complexity of the community became higher and the species distribution was more uniform.Short-term fence for 2 years,2013-2013,there are volatility.From 2014 onwards,Margelef species richness index,Shannon-Wiener and Simpson diversity index and Pielou,Alatalo evenness index show changes Regular,and fence>outside the fence.The diversity of the plant community inside and outside the fence shows that the heterogeneity coefficient is consistent with the trend of the Cody index.It shows that the heterogeneity of the fence inside and outside the fence is not great in the fence enclosure,and the plant species composition is not Alternative changes,but in 2016 the degree of differentiation of the community is more obvious.