| It's very difficult to get accurate land surface information in complex terrain mountain area. In consideration of biodiversity conservation and hydropower development, it's meaningful to do some research on finding suitable correction strategy and remote sensing classifier for detecting temporal and spatial variation of land use/land cover in the LRGR.Based on Nanting river basin on1988,1996,2002and2009TM/ETM+remote sensing images (cloud-free), DEM (30m) and GPS data, using remote sensing and GIS technology to probe suitable C correction strategy and remote sensing classifier for land use/land cover classification in the complex terrain, then analyze the land use/land cover change and its influence on the ecosystem services value at different scales in Nanting river basin during the past20years. The results show that:(1) All the three kinds of C correction strategy (sub-NDVI, sub-slope and sub-land use type correction) can eliminate the topographic effect quite well. Comparing with C correction, all of them can eliminate overcorrection at different degrees, especially the sub-and use type correction. Considering correction results of every band, sub-land use type C correction performs best in the second, the third and the seventh band, while sub-slope C correction performs well on the forth band and the fifth band. Although C correction can eliminate topographic effect in images, it can't improve the classification accuracy of land use/land cover in the study area.(2) The overall classification accuracy and kappa coefficient of Maximum Likelihood, Neural Networks and Support Vector Machine is higher than92%and0.80respectively, obviously better than other classifiers. The sorting of classification accuracy from high to low is Support vector machine, Maximum likelihood and Neural networks. In view of classification accuracy of each land use/land cover, forest land has the highest classification accuracy, followed by water area, farm land, building land and grassland, while garden land and unused land are the poorest.(3) The dominant land use/land cover pattern and advantage zone of each land use/land cover type varies with different terrain factors and scales of land use, even the same land use type may have large difference in amount and structure under different terrain scales. With the increasing of elevation, the area of grassland, forest land and garden land firstly increases and then decreases; the area of farmland is the smaller under the elevation of600-800m, while its area and proportion tends to be increasing continuously with the raising of altitude at the range of800-1800m; building land was mainly distributed in zone, where the elevation was less than1800m, water area and unused land was distributed in the elevation between400m and600m. Building land, water zone and unused land was mainly distributed in the zone, where the slope was less than10°. For the three types of landuse, the area and proportion declines with the increasing of slope. While, with the increasing of slope, the area and proportion of grassland, forest land, farmland and unused land firstly increases and then decreases; the area and proportion grows to the maximum under the slope between20°and30°,while farmland and garden land get the maximum under the slope between10°and20°(4) The change characteristics of land use vary with scales under Nanting river basin. Overall, the land use/land cover dynamic amplitude of riparian zone is the highest, followed by watershed scale which is higher than wide and flat valley segment of downstream. The active land varies vita the different kinds of scales. To the whole basin, the change amplitude of building land, unused land and grassland is high. While, under wide and flat valley segment of downstream, the change rate of building land, unused land and farmland is high. In the riparian zone, the change amplitude of building land, unused land and grassland is high. Under these three scales, the transformation and change rules of landuse/land cover are similar, which show the transformation from unused land to farmland and garden land. The transformation from forest land, farm land, garden land and grassland to farmland is quite obvious.(5)The ecological service function of Nanting river basin trends to be downward generally. The ecological service function decline of the riparian zone is the highest, followed by watershed scale which is higher than wide and flat vally segment of downstream. In accordance with classification, the value of ecosystem services of grassland, farmland and garden land tends to be increasing. The ESV of forest land and unused land tends to be declining. The ESV change of water area is not obvious. The farm land ESV of wide and flat vally segment of downstream firstly increases and then decreases, which is contrary to the forest land. The ESV of unused land continues to decrease, while the ESV of the water area doesn't change significantly. The ESV of forest land in riparian zone reduces significantly, which is contrary to arable land, while the ESV of grass land firstly decreases and then increases. |
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