坝上地区不同林龄樟子松防护林草本植物多样性研究

Study on herbaceous plant diversity of Pinus sylvestris var. mongolica shelter forest at different ages in Bashang area

为了解坝上地区不同林龄樟子松防护林林下植物多样性的变化规律,采用时空替代法,以承德御道口牧场3个林龄(16 a、29 a、40 a)的樟子松防护林作为研究对象,对其林下草本植物组成和多样性进行研究。结果表明:(1)3种林龄樟子松林下草本植物组成不同。16 a和29 a生樟子松林草本植物优势种为狗尾草,其重要值分别为21.23和18.88。40 a草本植物优势种为狗尾草和唐松草,其重要值分别为14.80和13.50。随着林龄增加,唐松草等多年生草本植物重要值增加,狗尾草等1 a生草本植物逐渐被取代,演替朝正方向进行。在樟子松林草本群落中菊科和禾本科是御道口坝上地区的优势科。禾本科、菊科共计9种,约占总数的33.33%。(2)随着樟子松林不断生长发育,林下草本Margalef丰富度指数、Simpson多样性指数、Shannon-Wiener多样性指数、Pielou均匀度指数和Alatalo均匀度指数均以40 a樟子松防护林最高,分别为2.02、1.80、0.76、0.73和0.70。(3)随着林龄的不断增加,群落相似性系数增加,29 a和40 a樟子松林下草本群落相似性系数最大值为0.6471,并且相近林龄的樟子松防护林林下草本群落比非相邻阶段的草本群落相似性更高。

In order to explore the change law of plant diversity in Pinus sylvestris var.mongolica stands at different stands ages,the space-time alternative method was used to study the plant diversity.Three different ages(16 a,29 a,40 a)of Pinus sylvestris var.mongolica shelter forest were chosen as the research objects to study the composition and diversity of understory herbaceous plants.The results showed:(1)The composition of the herbaceous plants in the three ages of Pinus sylvestris var.mongolica were different.The dominant species of 16 a and 29 a were Setaria viridis,with importance values of 21.23 and 18.88,respectively.With the age of the forest increased,the importance value of perennial herbaceous plants such as Thalictrum aquilegifolium var.sibiricum increased,and the annual herbaceous plants such as Setaria viridis were gradually replaced,the succession proceeding in the positive direction.In the herbaceous community of Pinus sylvestris var.mongolica,compositae and gramineae were the dominant families in the area in Yudaokou.There were 9 species of gramineae and compositae,accounting for 33.33%of the total.(2)With the continuous growth and development of Pinus sylvestris var.mongolica shelter forest,Margalef index,Simpson index,Shannon-Wiener index,Pielou index and Alatalo index of understory herbs Pinus sylvestris var.mongolica shelter forest of 40-year-old were the highest.The values were 2.02,1.80,0.76,0.73 and 0.70,respectively.(3)With the growth and development of Pinus sylvestris var.mongolica forest,the similarity of community increased.The forest of Pinus sylvestris var.mongolica that were 29a and 40a had the greatest similarity coefficient,the value of which was 0.6471.The herbaceous community of similar forest age under Pinus sylvestris var.mongolica shelter forest had higher similarity than the herbaceous community of non-adjacent stage.