秦巴山区土地利用时空格局及地形梯度效应

自然景观的垂直地带性为区域土地利用的垂直景观格局奠定了基础,同时也决定了垂直景观带上土地利用的强度及其变化情况。该文采用地形位指数、分布指数、土地利用程度综合指数和土地利用信息图谱法等,分析了1989-2010年秦巴山区土地利用格局的地形梯度效应和图谱信息,揭示地形控制下土地利用时空格局和土地转移的变化规律。结果表明:1)秦巴山区土地利用以林地和耕地为主,呈西林东耕分布;1989-2010年间林地减少显著,建设用地增加明显,其中耕地是建设用地主要转入来源,林、草地是耕地主要转入来源。2)秦巴山区各生态亚区用地类型差异明显,各生态亚区土地利用转移方向也存在差异性。3)秦巴山区土地利用强度指数呈东高西低,中高周低的态势;土地利用强度变化率稳定少动,增加趋势不明显;土地利用动态度呈中高周低的态势,整体变化不大。4)水域、建设用地和耕地主要集中在地形起伏度小和坡度小的低地形位,且耕地主要转移为其他两种用地类型,建设用地有向中低地形位分布的趋势。林地和草地集中在地形起伏大、坡度陡的中高地形位,且存在着相互转移演替现象,中低地形位往往是耕地、林地、草地间的相互转换,未来势必加强坡耕地和低山丘陵区林草地的管治工作。

Spatiotemporal pattern and terrain gradient effect of land use change in Qinling-Bashan mountains

Abstract: Land use/land cover change (LUCC) has attracted wide attention under the guidance of International Geosphere-Biosphere Program (IGBP) and International Human Dimensions Programme on Global Environmental Change (IHDP). The vertical zone of natural landscape lays the foundation for vertical landscape pattern of regional land use, and then the intensity and its change of land use in vertical landscape are also determined. Exploring the pattern and its spatiotemporal change of LUCC in Qinling-Bashan mountains can provide theoretical basis and practical guidance for regional ecological management and planning, soil and water conservation and sustainable land use. Based on terrain niche index, distribution index, land use degree composite index and geo-informatics map etc., LUCC data in 1989, 1995, 2005 and 2010 with the resolution of 1 km were collected, and the status quo, the terrain gradient effects and the geo-informatic map of land use patterns were analyzed to reveal spatiotemporal patterns of land use and change regulation of land transfer on the influences of terrain gradient during 1989-2010. The main results were summarized as follows: 1) Forestland and cropland were mainly land use types in Qinling-Bashan mountains and respectively accounted for 39.77% and 33.54%; forestland was mainly distributed in the west of Qinling-Bashan mountains and cropland was mainly distributed in the east of Qinling-Bashan mountains; forestland was significantly reduced by 6.788×105 hm2 but the constructed land was significantly increased by 5.347×105 hm2 from 1989 to 2010; the main conversions of land use patterns were from cropland to constructed land and from forestland and grassland to cropland; 2) The main land use type in each ecological subregion of the Qinling-Bashan mountains was obviously different and the direction of land use transfer in each ecological subregion was also different; the most extensive area of mixed forest in Qinling mountains was forestland and grassland with the transfer of forestland respectively to cropland and constructed land; the most extensive area in agricultural region of Nanyang Basin was cropland with the main transfer to constructed land; the most extensive area in deciduous broad-leaved mixed forest in Micang-Daba mountains was forestland with the main transfer to cropland; the most extensive area in evergreen and deciduous broad-leaved area in the Southwest mountains of Henan and agriculture and forestry district in the hilly area of middle Hubei Province was cropland and forestland with the main transfer from forestland to constructed land; the most extensive area in basin region of the upper Hanjiang River was grassland and cropland with the main transfer from grassland to cropland; 3) Land use degree composite index presented a feature that was high in the east and low in the west, and high in the middle and low in surroundings. The change rate of land use intensity was high in the middle and low in surroundings but was little on the whole. Land use degree composite index was agricultural region of Nanyang Basin > agriculture and forestry district in the hilly area of middle Hubei Province > evergreen and deciduous broad-leaved area in the Southwest mountains of Henan > basin region of the upper Hanjiang River > mixed forest in Qinling mountains > deciduous broad-leaved mixed forest in Micang-Daba mountains; 4) Water body, constructed land and cropland were mainly concentrated in the low terrain niche of low terrain and slope, cropland was mainly transferred to constructed land, and constructed land tended to be distributed in the middle-and-low terrain niche; forestland and grassland were concentrated in the middle-and-high terrain niche of high terrain and steep slope, and there was a phenomenon of mutual transfer and succession between them; stable model accounted for 72.1% and intermediate transition type accounted for 22.6%; distribution of cropland and forestland in terrain niche was very stable, but the tendencies of cropland transferred to constructed land and forestland transferred to cropland were very obvious in the middle-and-low terrain niche, and the mutual transfer among cropland, forestland and grassland often appeared in middle-and-low terrain niche and above. The expansion trend of human activity was concentrated toward the middle-and-low terrain niche. The future is bound to strengthen the management and governance of cropland, forestland and grassland in hilly area.