A Quantitative Study of the Vegetation Succession on the Abandoned Arable Lands of the Subalpine Meadows in Gannan Prefecture of Gansu Province I. Analysis of Community Composition
Abstract:The study of the succession of plant communities in the abandoned arable lands in the area of subalpine meadows of Gannan prefecture, is made by inferring from comparing the representative sites of abandoned arable lands of different ages. The analysis of community composition in succession shows (1) Importance of the grasses and sedge plants in the’ early stages of succession they rapidly dropped from 71% to 6% in 12 years, and as a result of the aggregation and spreading of grasses and sedge, plants, they recovered gradually to 30–40% the importance of weeds enhances rapidly in the early stage of succession and reduces in the later ones of succession; but the importance of poisonous herbs remains steady, acounting for about 10% of the community. (2) The species richness, Simpson′s diversity and eveness of the community increase while its dominance decreases with the development of succession. (8) The dominance diversity curve of the initial community is roughly geometric; as species are added, the curve approaches to a lognormal distributions but in the final stage, the curve approaches a MacArthur brocken-stick distribution.