Artificial Community Models Of Pioneers In The Karst Vegetation Deteriorate Areas Of Guizhou

The ecological system deteriorated by the people has threatened the survival environment in karst areas of Guizhou province. Ideas of restoration and reconstruction of ecological system were based on the fundamentals of ecology. Unfavorable factors are changed and deleted by the people, in order to restore the ecological system. The objects of their study are the degraded nature ecological system which done by natural calamities or people activities. Theory of community ecology is basis of the development of restoration ecology. Based on the principles of restoration ecology and main aim of karst vegetation restoration at present, take Huajiang Canyon with a typical degraded vegetation area located in southwest Guizhou as an example, we study bio-ecological features of the volunteer plants with some economic values and the soil environment, for the purpose of making some models of the pioneer plants to popularize. The ecological adaptations and leaf characters of 10 species of pioneer plant (belong to 6 families) were studied in Huajiang gorge. Guizhou province. At the same time, this paper also describes the fluctuation of soil nutrients and the contrast between soil of Leguminosae and non-vegetation covering. The results are as follows: 1) Despite the mesophyte leaf form of the ten pioneer species there were significant differences in leaf anatomical characters among them and some differences among different plants of an individual. These differences are mainly controlled by genetic factors, but environmental factors (mainly light and water or humidity) also had an important influence on them and these may oppose forms required in living methods; 2) Based on leaf adaptive characters the 10 species may be divided into 3 adaptive kinds: sun-adapted taxa or xerophytes (Broussonetia papyrifera, Pyracantha fortuneana, Robinia pseudoacacia, Trifolium repens); mesophytes(Toona sinensis, Zanthoxylum planispinum var.dingtanensis, Indigofera esquirolii, Lonicera japonica, Astragalus sinicus); and shade-adapted taxa (Stellaria media). 3) The soil moisture under the artificial community was twice that of non-vegetation slopes; topsoil moisture increased by more that 200% during the rainy season, but in the dry season the soil moisture under the introduced vegetation was close to or even lower than that of non-vegetation slopes. 4) Soil nutrient of Leguminosae also higher than non-vegetation soil; while organic matter and available K increased, there was no significant change in total N(it increased slightly); available P and soil pH decreased. Changes of soil nutrients occurred mainly in the topsoil. Base on the results of this study, we advance ten models of pioneer community for the purpose of popularization.