Assessment of system functions after vegetation restoration of the degraded ecosystem in arid-hot valleys of Jinsha River:A case study on small watershed of Yuanmou

To aim at the problems of the dry-hot climate, outstanding inconsistent of water-heat, low vegetation coverage, serious soil erosion, intense degradation of ecological environment and the difficulty of vegetation restoration, this paper summarized the vegetation restoration technique system in the dry-hot valleys and analyzed the functions of soil and water conservation, climate improvement, and biological diversity increase of vegetation restoration on the ecosystem in the dry-hot valleys. The investigations of the ecosystem biodiversity were carried out on the analysis of the relationship between biodiversity and ecological function of the two ecosystem patterns: artificial restoration forest and the natural by enclose on the high degraded land. The results showed that the soil erosion rate decreased significantly after the vegetation restoration, and the degraded land also decreased with the reduction of 22.03%, 21.15% and 34.15% for the low, moderate and high degraded land, respectively. The climate environment of the small watershed showed an apparent improvement after the vegetation restoration, since the temperature decrease and the humidity increase that led to reduce the inconsistent of water-heat. The natural restoration by enclose ecosystem is useful to the biodiversity, the improvement and the stability of the ecosystem, and the Leucaena artificial restoration forest reduced the species diversity but optimized the ecological function. Therefore, as to the high and extremely high degraded ecosystem in the dry-hot valleys, the Leucaena pattern of gully control and natural restoration by enclose are the relatively optimal measures.