浙江省丽水市莲都区水源涵养功能动态变化及发展趋势

水源涵养功能是生态系统服务功能中重要的一项。了解区域水源涵养功能的现状和未来变化，对水源涵养保护与利用有重要意义。以浙江省丽水市莲都区为研究范围，利用InVEST模型对研究区1994，2001，2008和2015年的水源涵养功能进行了计算评估及重要性评价，利用CA-Markov模型对研究区2030年的土地覆被类型进行了预测，并进行水源涵养功能评估。结果表明:莲都区1994，2001，2008和2015年的平均水源涵养量分别为69.98，98.40，82.36和114.01 mm，水源涵养总量分别为1.11×108，1.56×108，1.23×108和1.83×108 m3，水源涵养功能21 a间提高了62.92%。研究区南部地区和北部部分地区水源涵养功能较好，中部地区的水源涵养功能低于其他地区。影响研究区水源涵养功能最主要的两类因素是下垫面特征和气候因素，其中土壤饱和导水率为影响最大的因素，标准化系数达到了0.644。2030年模拟结果显示，莲都区水源涵养功能与2015年差异不大，平均水源涵养量和总量分别为112.90 mm和1.81×108 m3。通过水源涵养功能评价模拟，发现研究区的西北地区水源涵养潜力较大。

Dynamic changes and development of water retention in Liandu District

Water retention, a most important ecosystem service that is key to water source protection planning, reflects the ability of an ecosystem to keep the water, as well as showing water available for human consumption. To better understand the characteristics of water retention and to better protect the water environment of Liandu District in southwest Zhejiang Province, this study evaluated the quantity and spatial characteristics of its water retention. The assessment was carried out using the InVEST (integrated valuation of ecosystem services and tradeoffs) model. Then a simulation of water retention for Liandu in 2030 was conducted by the CA-Markov Model. The main results showed that from 1994 to 2015, the city area increased by 6.11×104 hm2, the total area of forest increased 1.35×104 hm2, and by contrast, the rocky area decreased 1.91×105 hm2. For the study area the average water retention in 1994 was 69.98 mm, in 2001 was 98.40 mm, in 2008 was 82.36 mm, and in 2015 was 114.01 mm; total water retention in 1994 was 1.11×108 m3, in 2001 was 1.56×108 m3, in 2008 was 1.23×108 m3, and in 2015 was 1.83×108 m3. Overall, water retention increased 62.92%. Underlying surface and climatic features were the two greatest factors affecting water retention with soil hydraulic conductivity, having a standardized coefficient of 0.644, being the most important. Also, a large difference in spatial distribution for different time periods was found. In general, the southern and northern parts of the study area had better water retention with the central parts not as good. The simulation showed that the average water retention of the study area was 112.90 mm, and total water retention was 1.81×108 m3 with the northwest region having a greater water retention potential. Thus, combining the InVEST Model and CA-Markov Model provided a favorable reference for effective management of water retention.