Distribution Patterns Of Vegetation And Its Environmental Driving Mechanism In Sphagnum Wetland Of Qizimei Mountain

Wetland vegetation distribution is the spatial representation of wetland plant species composition,which has an important indicator effect on wetland ecological environment,reveals the environmental driving mechanism affecting the distribution pattern of wetland vegetation community,and is of great significance for wetland protection and utilization.This paper takes the Sphagnum wetland of Qizimei mountain as the research object.In June 2021,the Sphagnum patches of the wetland were set quadrats in the 9th row,the Dingzitai and the10 th row of the Shaiping of the Qizimei mountain Sphagnum wetland.The vegetation and environment were investigated by using standard sample method,and the plant number,height and coverage data were investigated and recorded.At the same time,Sphagnum palustre and soil samples were collected for growth index,physiological and physicochemical measurement and analysis.Statistics and related software were used for data statistical analysis,hoping to explore:(1)The vegetation community characteristics and community types of the sphagnum wetland in Qizimei mountain;(2)The main environmental factors affecting the vegetation distribution in the Sphagnum wetland of Qizimei mountain;(3)The distribution pattern and its environmental driving mechanism of Sphagnum palustre.community in Sphagnum Wetland of Qizimei mountain.The main conclusions are as follows:(1)A total of 37 plant species belonging to 34 genera and 25 families were counted in 37 quadrats,including 3 arbors,all of which were artificially felled to generate seedlings;8species of shrubs,all seedlings;2 species of lianas;23 kinds of herbs;1 species of Bryophyte.According to families and genera,there were many plants in the family Juncaceae,Ericaceae,Rosaceae,and Asteraceae.Among the 37 plant species,there were some species with high dominance,among which there were more species with high dominance in the herbaceous layer,such as: Carex rubrobrunnea var.taliensis,Pteridiumaquilinum var.Latiusculum,Hostaventricosa,etc.The only bryophyte was Sphagnum palustre.(2)Based on the results of systematic clustering analysis,a total of 37 field samples were divided into four associations: I.Ass.Pteridium aquilinum-Sphagnum palustre;II.Ass.Carex rubrobrunnea var.taliensis-Sphagnum palustre;III.Ass.Juncus setchuensis +Cnidium monnieri-Sphagnum palustre;IV.Ass.Hosta ventricose +Lycopus cavalerieiSphagnum palustre.(3)From Ⅰ ～Ⅳ,the three indexes of Patrick index(R),Shannon-Wiener index(H)and Simpson index(D)showed a trend of rising and then falling after decline,and the lowest was in cluster II.and highest in cluster III.The Pielou index(E)was Contrary to the change trend of the other three indexes,it presents a trend of first rising,then falling,and then rising.The interspecific competition of vascular plants in the quadrat affected the species diversity to some extent.(4)Redundancy analysis showed that the 13 environmental factors accounted for 50.5%of the variation of wetland plant composition,which could well explain the spatial distribution characteristics of wetland species.The cumulative interpretation rate of the first two axes was 30.13%,accounting for 72.15% of the total interpretation rate.The first axis mainly reflects the changes of plant species and community along soil p H,groundwater level and soil TK content.The second axis mainly reflects the variation trend of species along soil AHN and soil TN content.In general,groundwater level,soil p H value and soil TK content were the main environmental factors affecting the growth and distribution of the vegetation in the sphagnum moss wetland of Qizimei mountain.(5)There were significant differences in nine physiological indexes(TN,TP,TK,TC,TOC/TN,TOC/TP,TN/TK,water content)and four growth indexes(plant height,number of cephalic branches,coverage and biomass)among the four clusters.From Ⅰ to Ⅳ,the four growth indexes of Sphagnum showed a gradually decreasing trend,and all of them were the lowest in cluster Ⅳ.(6)The results of Multiple linear regression analysis and Pearson correlation analysis showed that showed that water table and soil TN/TK were principal environmental factors affecting growth and distribution of S.palustre populations in Qizimei Mountain.In this study,excessive water content in S.palustre tissue caused by prolonged flooding stress inhibited its photosynthesis,which further impede the growth.On the other hand,high N load led to S.palustre growth was limited by K,resulting in unbalanced nutrient absorption and thereby inhibiting its growth and development.Nitrogen input from nearby farmland may be an important factor caused excessive TN/TK ratio in both soil and S.palustre in association IV.