Effects of constructing mixed forests on understory shrub and herb species diversity after clear-cutting of Eucalyptus grandis pure forest
Understory plant diversity is an important indicator of forest community structure and function.However,the impact of understory plant diversity in pure artificial forests after clear-cutting into mixed forests remains unclear.Therefore,in this study,the replacement and transformation demonstration site of Eucalyptus grandis pure forest in the Shawan District of Leshan City,Sichuan Province,China,was investigated.To study the effect of mixed forests on the diversity of understory shrub and grass plants,we selected 5-year-old mixed forests of Prunus persica'Atropurpurea'+Malus × micromalus,Cunninghamia lanceolata+Phoebe zhennan+Prunus persica'Atropurpurea',and Cinnamomum camphora+Metasequoia glyptostroboides as well as pure forest of E.grandis.All forests were recently constructed after clear-cutting the E.grandis.The results showed that the number of understory vegetation species increased significantly in mixed forests compared to pure forest of E.grandis,with C.lanceolata+P.zhennan+P.persica'Atropurpurea'forest being the richest in understory plant community composition.The species richness(R),Simpson(D),Shannon-Wiener diversity(H-),and Pielou evenness indices(Jsw)were significantly higher in the shrub layer of the three mixed forests than in the pure E.grandis forest,whereas no significant differences were observed in the herb layer.Among the three mixed forests,the highest plant diversity in the shrub and herb layers was found in the C.camphora+M.glyptostroboides and C.lanceolata+P.zhennan+P.persica'Atropurpurea'forests,respectively.Soil pH,soil water content,total nitrogen,total phosphorus,total potassium,and organic matter content of mixed forests showed increasing trends,whereas soil bulk density and porosity showed decreasing trends.The redundancy analysis results showed that the soil organic matter content was the main factor affecting the understory diversity of vegetation.In conclusion,understory plant species diversity increased in the initial stage after the conversion of pure E.grandis forest into mixed forests,and soil organic matter content was the main factor influencing the diversity of understory plants.
万方数据
维普
