| In this paper, the current situation of riparian vegetation was investigated and analyzed abouting the main river of Dong-jiang within Guangdong province. At the same time, the paper proved the degradation factors. The paper's main findings are as follows:1. After field survey, the plants of riparian vegetation on main river within Guangdong are 241 species, belonging to 67 families and 199 generics. The majority of Dicotyledon is 44 families,130 generics and 157 species, and the percentage of the total number of species is 65.1%. The Monocotyledons are 10 families,52 generics and 68 species, accounting for 28.2%. The Gymnosperms are 9 families,11 generics and 11 species, accounting for 4.6%. The Ferns are 4 families,5 generics and 6 species, accounting for 2.5%.2. The great families, middle generics constitute the main body of the flora and species, and they are Gramineae, Leguminosae, Compositae, Euphorbiaceae and Cyperaceae Small and single generics constitute the main species. The 241 kinds of plants includes 52 species of trees,51 species of shrubs,127 species of herb and 11 species of vine. The distribution of families is characterized by more of worldwide distribution, dominant component of tropical distribution and certain proportion of temperate elements. The distribution of generics is characterized by certain proportion of worldwide distribution and temperate elements, dominant component of tropical distribution and less specific components.3. The vegetation in the study area is divided into six vegetation types and 21 formations. From upstream to downstream, spatial distribution of riparian vegetation is characterized by transition from the mountains to the plains vegetation。Low beach near the water mainly is herb, evolving from the herb to shrub and from the shrub to tree along riparian direction. The vertical structure of vegetation is 7 main types, and three-tier structure with grass, bushes and tree is dominant, accounting for nearly 35%. The dominant plant species are 13 species of trees,11 species of shrubs,31 species of herbs and 4 species of vines.4. Riparian use land can be divided into six categories:woodland, grassland, artificial garden, farmland, built, and the other. The general topography of the Dong-jiang river valley is northeast high, southwest low and at 3～179 m above sea level. Upstream riparian vegetation is mostly mountainous landscape vegetation, Downstream is plains vegetation landscape and the middle river is both mountain vegetation and plains vegetation landscape.5. Woodland and farm land constitute main use land of the four typical segments, followed by the building land. The total vegetation coverage of A, B, C and D segments respectively is 78.0%,85.5%,81.4%,65.7%. Sections of vegetation coverage is linked to the degree of intensity of which the corresponding segment affected by human activities. 4 typical segments of riparian vegetation mainly are composited of forest and farmland. The influencing factors of riparian vegetation include natural and human factors. The strength of human activities on the riparian vegetation is orderly Upstream |
PDF Full Text Request