PROGRESS IN GEOGRAPHY ›› 2019, Vol. 38 ›› Issue (4): 588-599.doi: 10.18306/dlkxjz.2019.04.011

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Characterizing water purification services and quantifying their driving factors in watershed terrestrial ecosystems

Yang LIU1,2(), Jianshu LV3, Jun BI4   

  1. 1. Business School, University of Jinan, Jinan 250002, China
    2. Shandong Longshan Green Economic Research Center, Jinan 250002, China
    3. School of Geography and Environment, Shandong Normal University, Jinan 250014, China
    4. School of the Environment, Nanjing University, Nanjing 210046, China
  • Received:2018-10-04 Revised:2019-02-02 Online:2019-04-28 Published:2019-04-28
  • Supported by:
    National Natural Science Foundation of China, No. 41701604 and 41601549;Natural Science Foundation of Shandong Province, No. ZR2017BD003;Doctoral Foundation of University of Jinan, No. 16010023.


Water purification services of the terrestrial ecosystem can filter out pollutants in surface runoff, which helps to reduce emissions into the water body. Therefore, improving these services is an effective way to control non-point source pollution in watersheds, and accurately quantifying the spatiotemporal characteristics and driving factors of change of the services is the precondition for such improvement. Purification services for nitrogen and phosphorus are two typical water purification services, which can be quantified by nitrogen and phosphorus exports as the reverse proxy indicators. Taking a representative area of the Taihu Lake Basin in 2000-2010 as a case, we used the nutrient purification model in the Integrated Valuation of Ecosystem Services and Tradeoffs (InVEST) tool to quantify nitrogen and phosphorus indicators of terrestrial ecosystem. The spatial pattern and temporal variation of purification services for nitrogen and phosphorus were characterized by the spatial analysis method in ArcGIS. In order to quantify the driving factors of change of the services, we developed a panel data model based on 31 selected factors and GIS spatial statistics methods. The results show that there were obvious spatial heterogeneities between nitrogen and phosphorus indicators and change over time. Both nitrogen and phosphorus purification services showed a spatial characteristic of widely weak decrease from 2000 to 2010, with the areal ratios of 59.19% and 58.27%, respectively. With regard to the temporal variation of service amount, nitrogen purification service of the study area first reduced then increased slightly during 2000-2005 and 2005-2010, and the increase in Suzhou urban district, Wuxi urban district, and Kunshan City were obvious. Phosphorus purification service was always in decline during 2000-2005 and 2005-2010, and the urban districts of Wuxi and Suzhou experienced the largest reduction. Water purification services are influenced by multiple driving factors in the physical, social, and economic domains. Climatic factors and water network density had significant positive influences on these two services, while the negative driving factors differed. Arable land proportion, village density, and agricultural population density had major negative effects on nitrogen purification service; while urban land density mainly impacted negatively on phosphorus purification service. Therefore, appropriate measures should be implemented to improve these two water purification services according to the driving factor analysis. Climate change adaptation policy can contribute to synergistically manage nitrogen and phosphorus purification services. Meanwhile, different control measures should be taken because of the varied driving factors between nitrogen and phosphorus purification services. Improving production and living conditions in rural areas and guiding individual behaviors of farmers can help to reduce the impact of agricultural activities on nitrogen purification service. Adjusting production and daily living activities in urban areas can reduce phosphorus emissions and enhance the phosphorus purification service of the terrestrial ecosystem. This study can provide support for non-point source pollution control and water management in watersheds.

Key words: terrestrial ecosystem, water purification services, spatiotemporal variation, driving factor, Taihu Lake Basin