Recovery Dynamics of Vegetation and Soil Properties in Karst Rocky Desertification Areas in Guizhou, China

摘要

Dynamics of vegetation and soil properties responses to vegetation recovery in the selected 72 Karst desertification sites in Guizhou, China were studied. Six typical and representative vegetation types along a chronosequence of vegetation recovery (corn land, sparse grass, regeneration forest, shrub, grass and shrub, and native forest with 0, 3-5, 10-15, 20-30, 30-40, and >100 yrs, respectively) were selected for the study of the plant species, vegetation features as well as soil physical & chemical properties in order to assess interaction between soil properties and vegetation structure. It was found that vegetation species had dry-resistant characteristics because of their extensive exposure to the basement rocks and thinness soil. Grass community was always coarse grass, shrub was generally dominated by vines, thorn bushes and tree species were almost leather-like, single and mini-type leaf plants. Factor analysis showed that the 3 factors, soil fertility, pH and clay, explain 67.97 % of total variance among the 19 soil property parameters. Soil fertility changed significantly effects included the increasing of soil organic matter, total and available nitrogen, humic acid, CEC, fuvic acid, exchange Ca, porosity and total P but decreasing bulk density. This trend was followed by enhancing of bio-enrichment capacity along the chronosequence of vegetation recovering process. Soil pH had no significant correlation with the vegetation recovery stages because it was determined by soil forming process and characteristic of parent materials. The factor clay only decreased slightly in the recovery stages. Cluster analysis indicated that vegetation structure could develop within short time under anthropocentric interfering, but soil fertility only accumulated with annual litter decomposing. We can conclude that recovery of vegetation community structure proceeded restoration of soil function.