Analysis Of Vegetation Dynamics And Its Causes Of Loess Plateau

One of hot topices in cological research is response of vegetation change on global climate change in recent years. The Changing vegetation are climate and human activities. Loess Plateau located in China's Ecologically sensitive areas. It has an important theoretical and practical significance to the work of environment to study the relationship between climate and human activities and vegetation. This paper analyzes the Loess Plateau climatic factors (temperature, precipitation) spatial distribution and variation by 2000-2014 meteorological data; analyzes the spatial distribution of vegetation cover and changing rules by MODIS NDVI and Landuse data in 2000-2014; analyzes the vegetation response mechanisms to climate variation in the Loess Plateau; analyzes role of human activity in the vegetation cover. These main conclusions are as follows:1?Distribution from the spatial pattern of vegetation NDVI in Loess Plateau, growth trend of the area is 92.88%, decreasing trend of the area is 7.12%. Among them, significant growth trend of the area is 12.52%, mainly located in the middle areas of the Loess Plateau, for example, north mountain deciduous forest; extreme growth trend of the area is 56.69%, located in the central region of the Loess Plateau, for example, eastern Inner Mongolia grassland area, grassland area of the Loess Plateau in north-central, north mountain deciduous forest, deciduous broad-leaved forest Weihe. From season yardstick, it has greater spatial difference in spring NDVI, summer NDVI and autumn NDVI. Summer NDVI and autumn NDVI have an larger increasing trend, account for the total area of the study area is 93.08% and 90.78%. Spring NDVI has an increasing trend in the area less than that of two other seasons, Spring NDVI has an decreasing trend in the area more than that of two other seasons, account for the total area of the study area 83.34%?16.66%.2?Distribution from the vegetation NDVI temporal pattern, overall are increasing trend(rate of increase is 0.0057). The rate of increase from 2000 to 2014 is 0.33 to 0.43. There is a sharp increase in the growing season NDVI value after 2011. Due to changes in temperature and precipitation over the same period, there has been growing greater volatility in season NDVI. Spring NDVI, summer NDVI and autumn NDVI showed an increasing trend. Among them, Summer NDVI is the maximum rate of increase(R=0.84, p<0.00006), autumn NDVI has the most significant increasing trend(R=0.88, p<0.00007).3?From analysis of the response of vegetation NDVI and climatic factors in the Loess Plateau, Loess Plateau NDVI and precipitation was positively correlated significantly larger than the area of NDVI was positively correlated with air temperature area. Three seasons NDVI and precipitation was a significant negative correlation area smaller than NDVI and the temperature significantly negative correlation area. Precipitation on the Loess Plateau vegetation growth has a great enhancement. Whether seasonal or during the year, impact on vegetation precipitation is higher than the temperature effect.4?Obtained using linear regression analysis, agricultural production, ecological construction and other human activities are also important factors in vegetation cover changes. Vegetation in the Loess Plateau showed an increasing trend. Increase agricultural production levels resulting in rising rural areas NDVI, in addition, Ecological economic benefits arising from the construction of vegetation?afforestation? reforestation.