Spatial Distribution Of Herbaceous Plant Communities And Environmental Interpretation In Shandianhe Wetland, Zhangjiakou Highland

To explore the structure characteristics,difference and its environmental impact factors of plant community in different types of wetland(artificial wetland,marsh wetland,river wetland and lake wetland).The coverage,diversity,species richness and biomass of different types of wetlands were investigated in June,July,August and September in 2016.Meanwhile,the soil pH,organic matter,nitrogen,phosphorus and potassium contents in the wetland of Shandianhe wetland were measured in July 2016.The community structure characteristics and environmental factors of herbaceous plants under different wetland types were discussed by use of redundancy analysis method.The results showed that:(1)Through four months consecutive investigation of herbaceous plants in Shandianhe Wetland Park,a total of 186 species of herbaceous plants,116 genera and 37families were found.The number of plant species found in July was the largest,with 140species of 86 genera of 30 families,and only 67 species of 52 genera in September.In artificial wetlands the largest number of plant species was found in August,but in other wetlands that was found in July.The number of plant species in constructed wetlands,river wetlands,marsh wetlands and lake wetlands was 126 species,114 species,96species and 86 species respectively.The mean value of the dominant species in the swamp wetland was the largest,which was 50.72%,indicating that the dominant species in swamp wetland occupied the largest niche space.(2)In June and September,the Simpson diversity index and Shannon-Wiener diversity index of river wetland plant communities were the highest.However,the Simpson diversity index and Shannon-Wiener diversity index of artificial wetland plant communities were the highest in August,being 0.67 and 1.59,respectively.In July,the Margalef index of plant communities in river wetlands was the largest,2.18.On the whole,the variation of the diversity of community in Shandianhe wetland is more disturbed in the time gradient,and the variation patterns of the diversity among different wetlands are different.(3)The community biomass of artificial wetland reached the maximum of 282.79g/m~2 in August,however,the other wetlands reached their maximum biomass in September.In the first few months of the lake wetlands,the number of plant species and species diversity was at a relatively low level,but in September,the biomass of plant communities reached 846.22 g/m~2,which was the highest among the four wetlands.The average biomass of various wetland plant communities during the four months,ranging from more to fewer,was river wetlands,marsh wetlands,lake wetlands,and constructed wetlands.(4)There was a more neutral pH value in artificial wetlands,the average content of organic matter was also highest in 4 types of wetlands.The nitrogen,phosphorus,potassium and other nutrient contents in marsh wetlands and lake wetlands are basically higher than those of artificial wetlands and river wetlands.Compared with different soil layers,the soil pH value in Shandianhe wetland has not changed significantly,and the soil organic matter content increases with the deeper soil layer.The content of nitrogen,phosphorus and potassium was basically decreased with the depth of soil.The content of organic matter and total nitrogen in the Shandianhe wetland is at the first or second level of the national second soil screening nutrient classification standard.The average total phosphorus content was 0.17 g/kg~0.25 g/kg and the average available P content was2.19 mg/kg~3.88 mg/kg,all at the fifth or sixth level.Thus,the phosphorus content is relatively insufficient.The total phosphorus and total potassium were significantly correlated with the available P(P<0.05),and it was significantly correlated with other indicators(P<0.01).This indicates that total phosphorus and potassium can be used as indicative indicators of soil nutrient distribution in the Shandianhe wetland.(5)Redundant analysis(RDA)sorting results show that there are significant differences in the internal environment of artificial wetland and the distribution of herbaceous plants,and the environmental difference between northeast and southwest of artificial wetland was the first reason.The important value of Carex heterolepis Bunge is higher in swamp wetland,which was mainly influenced by soil nitrogen and potassium.The distribution of plant species in river wetlands is mainly affected by the soil pH value.The potassium and pH value of lake wetland are higher,and the organic matter content is lower.Among the selected 8 types of soil factors,the content of soil available P total nitrogen and available N were the mainly factors which affecting the structure characteristics of wetland herbaceous plant community.