| Grassland, the material basis for national economic development, which is enormous ecological barrier and has environmental maintenance function, plays an important role in human survival and development. Grassland Above-ground Net Primary Productivity(ANPP) and its dynamic can reflect the growing ability of grass, playing a vital role in the process of global change and adjusting the ecosystem. Clarifying the quantity, quality, productivity, condition of grassland and its driving factors is of great importance to the management and protection to grassland. This paper takes eastern Inner Mongolia grassland as the research object, bases on Landsat TM/OLI images, MODIS data, field survey data and the measured data, by means of remote sensing, Arc GIS spatial analysis method and SPSS statistical analysis functions to extract the grassland distribution information of eastern I nner Mongolia from 2000 to 2013, analysing the grassland landscape pattern and dynamic characteristics. Vegetation index-based model was established to estimate the grassland ANPP and examine the spatial and temporal pattern and influence factors. This study is looking forward to provide scientific basis for regional scientific management, protection and restoration of grassland. The basic conclusions are concluded as follows:1. Based on Landsat TM/OLI data and object-oriented-decision tree classification method, this paper gets grassland distribution information of eastern Inner Mongolia from 2000 and 2013. The overall accuracy of classification result is 92.41% and the Kappa coefficient is 0.92. Grassland is one of the major land types of eastern Inner Mongolia, which mainly distributes in the Midwest of Hulunbeier high plains, and also distribute in southeast of Grand Khingan and west Liaohe river mountain plain area.2. From 2000 to 2013, the grassland area reduced by 314.72 km2, the reduction rate was 23.08 km2/a. As a whole, the grassland of eastern Inner Mongolia presented a shrinking trend. Grassland was mainly turned into farmland, wetlands and artificial surfaces, accounting for 79% of grassland conversion to other types land. Grass patch number and patch density were both in decline, and the Shape tended to be irregular and also the degree of aggregation decreased. The centroid of grassland transferred from the southeast to the northwest. Grassland area of Hulun Buir increased, while the grassland area of Hinggan League, Chifeng, Tongliao were all reduced, Among them, the grassland area of Chifeng experienced the largest shrinkage.3. Using field survey data and vegetation index, We established grassland productivity estimation model. The optimal simulation model of eastern Inner Mongolia grassland was y = 69.237RVI0.5225(R2=0.6391). This model conducted spatial inversion of the grassland productivity of eastern Inner Mongolia.4. Result showed that annual grassland ANPP was 365.56 g·m-2·a-1 from 2000 to 2013.The largest grassland ANPP occurred in 2013, while the lowest grassland ANPP occurred in 2000(252.51g·m-2). During 2000 to 2013, the annual averaged ANPP were different in the four cities of research area, among which, Hinggan League(444.4 g·m-2·a-1) > Hulun Buir(351.2 g·m-2·a-1) > Tongliao(343.1 g·m-2·a-1) > Chifeng(338.7 g·m-2·a-1).Using annual ANPP of grassland and the precipitation and temperature in eastern Inner Mongolia from 2000 to 2013 to make correlation analysis, the result showed that the annual grassland ANPP has a clear correlation with temperature. Human activities imposed important influence on the grassland ANPP. The shorter distance with the settlement place had the more influence to grassland ANPP. National policy is of great significance for the protection of grassland productivity. |
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