Relationship Among Vegetation Cover, Climate Change And Human Activities In Ordos Plateau

Response of vegetation change to global climate change is a hot issue in ecology research. And vegetation change was mediated by human activities and is the most important factor to effect the vegetation change, so the vegetation change is decided by climate change. Ordos plateau locates in the ecologically sensitive area of the western China, its vegetation change and a response to climate change is very important. In this study, changes of climate and vegetation and their relationship, and the influence of human activities in the Ordos plateau were estimated used the climate indexes of47a and the NOAA/AVHRR NDVI8km dataset. Main results and conclusions were as follow:(1)From1961to2007, the mean air temperature of Ordos plateau was7.33℃, showed a significant rised(R2=0.5927, P<0.0001), the rising rate was0.48℃/10a. Space distribution of air temperature showed an increase from east to west. Annual precipitation was280.26mm, no significant change observed(R2=0.0349, P=0.1555). Space distribution of annual precipitation showed a decline from east to west, and the typical steppe has the higher precipitation in this area.(2)During1982-2006, annual mean NDVI of Ordos Plateau increased significantly (p=0.0017), increasing rate was0.14%yr-1. During the same period, the mean temperature also increased significantly (p=0.0007) while the mean precipitation didn’t show significant change (p>0.05). In Ordos Plateau, the NDVI increment was mainly contributed from the typical steppe, which seasonal average NDVI of spring, summer and autumn all increased significantly(p=0.0000). In the growing season of Ordos Plateau, the main driving factor for the increment of NDVI was precipitation, while in the non-growing season it was temperature.(3)During1982-2006, human activity firstly had a negative effect to the Ordos plateau vegetation, and followed by positive effect. During1990-1999, human activity had negative effect in most area of the Ordos plateau, while after2000, human activities showed more positive effect on the vegetation.