太行山淇河流域2000-2015年土壤侵蚀和水源供给变化研究

Soil erosion and water supply change in Qihe watershed of Taihang Mountains from 2000 to 2015

山地生态系统的土壤侵蚀和水源供给变化对评估区域生态环境质量有重要意义。基于2000-2015年四期土地利用数据,借助In VEST模型对淇河流域近16年间山地生态系统的土壤侵蚀和水源供给变化进行评估。结果表明:(1)研究区主要土地利用类型为耕地、草地和林地,共占流域总面积的90%以上。近16年间淇河流域的耕地面积显著减少,草地和水域面积大幅增加,建设用地扩张明显。(2)平均土壤侵蚀模数显著降低,2000年土壤侵蚀模数为154.27 t/(hm^2·a),2015年减少到32.09 t/(hm^2·a);强度侵蚀、极强侵蚀和剧烈侵蚀由9.03%、12.19%和25.96%分别减少到7.17%、6.36%和4.21%,微度侵蚀、轻度侵蚀和中度侵蚀由24.31%、16.96%和11.57%增加到41.89%、27.71%和12.68%;退耕还林、还草措施优化了土地利用格局,促进植被恢复,对治理土壤侵蚀起到了显著效果。(3)水源供给量整体呈现先增加后减少的趋势,2005年达到峰值(1.79亿m^3)。相邻两期水源供给量增减变化不一,2000-2005年水源供给量增加的面积大于减少的面积,其水源供给的量值也呈增加趋势,水源供给能力整体增强;而2005-2010年、2010-2015年的水源供给能力随之减弱,其中,2010-2015年水源供给减少的较小;林地和草地面积的增加造成水源供给量降低,土壤水源涵养能力增强。土壤侵蚀和水源供给是山地生态脆弱性响应的重要指标,制定合理的水土保持措施对增强山区生态系统的服务能力具有重要意义。

The changes of soil erosion and water supply of mountain ecosystem plays an important role in assessing regional ecological environment.Based on four-stage land use change data from 2000 to 2015,this study assessed the changes of main ecosystem services in Qihe watershed of Taihang Mountains with the assistance of In VEST model.The results showed that：（1）The main types of land use were cultivated land,grassland,and woodland accounting for more than 90%of the total area of the Qihe watershed.During the 16-year study period,cultivated land decreased obviously,and grassland,water,and construction land all increased.（2）The soil erosion modulus decreased from 154.27 t/（hm^2·a）in 2000 to 32.09 t/（hm^2·a）in 2015,indicating that the average soil erosion modulus decreased obviously from2000 to 2015.The area rates of land with strong erosion,extreme erosion,and severe erosion decreased from 9.04%,12.19%and 25.96%to 7.17%,6.36%and 4.21%,respectively,while those of land with slight erosion,mild erosion,and moderate erosion increased from 24.31%16.96%and 11.57%to 41.89%,27.71%and 12.68%,respectively.The measures of returning farmland to forest and grassland have optimized the land use pattern,promoted vegetation restoration,and played a significant role in soil erosion control.（3）The volumes of water supply in the watershed increased firstly and then decreased during 2000-2015,and reached the peak of 179 million m^3in 2005.The volumes of water supply in two adjacent periods were different.The increased areas and volumes of water supply were more than decreased areas and volumes from 2000 to 2005,showing that the water supply capacity was enhanced.However the water supply capacity weakened during 2005-2010 and 2010-2015,with the latter period seeing a smaller reduction.The increase of forest land and grassland area resulted in the decrease of water supply and the enhancement of soil water conservation capacity.Soil erosion and water supply are important indicators representing mountain ecological vulnerability.It is important to take concrete measures in soil and water conservation so as to enhance the service ability of mountain ecosystem.