State Key Laboratory of Earth Surface Processes and Resource Ecology, Beijing Normal University, Beijing 100875, P.R. China; College of Resources Science and Technology, Beijing Normal University, Beijing 100875, P.R. China.
College of Architecture, Urban and Rural Planning, Hunan University of Technology, Zhuzhou 412007, P.R. China.
Sci Total Environ. 2016 May 1;551-552:205-16. doi: 10.1016/j.scitotenv.2016.01.162. Epub 2016 Feb 12.
Understanding the relationships between land use patterns and water quality in low-order streams is useful for effective landscape planning to protect downstream water quality. A clear understanding of these relationships remains elusive due to the heterogeneity of land use patterns and scale effects. To better assess land use influences, we developed empirical models relating land use patterns to the water quality of low-order streams at different geomorphic regions across multi-scales in the Dongjiang River basin using multivariate statistical analyses. The land use pattern was quantified in terms of the composition, configuration and hydrological distance of land use types at the reach buffer, riparian corridor and catchment scales. Water was sampled under summer base flow at 56 low-order catchments, which were classified into two homogenous geomorphic groups. The results indicated that the water quality of low-order streams was most strongly affected by the configuration metrics of land use. Poorer water quality was associated with higher patch densities of cropland, orchards and grassland in the mountain catchments, whereas it was associated with a higher value for the largest patch index of urban land use in the plain catchments. The overall water quality variation was explained better by catchment scale than by riparian- or reach-scale land use, whereas the spatial scale over which land use influenced water quality also varied across specific water parameters and the geomorphic basis. Our study suggests that watershed management should adopt better landscape planning and multi-scale measures to improve water quality.
了解低阶溪流土地利用模式与水质之间的关系，对于有效进行景观规划以保护下游水质非常有用。由于土地利用模式的异质性和尺度效应，这些关系仍难以清晰理解。为了更好地评估土地利用的影响，我们采用多元统计分析方法，在东江流域多个地貌区域多尺度上，针对不同的水流路径缓冲区、河岸带和流域尺度，建立了土地利用模式与低阶溪流水质之间的经验模型，用以关联土地利用模式。土地利用模式采用土地利用类型的组成、配置和水文距离等指标进行量化。在夏季基流条件下，我们对 56 个低阶集水区进行了采样，这些集水区被分为两个同质地貌组。结果表明，低阶溪流的水质受土地利用配置指标的影响最大。在山区集水区中，耕地、果园和草地的斑块密度较高，水质较差；而在平原集水区中，城市土地利用的最大斑块指数较高，水质也较差。与河岸带或水流路径尺度相比，流域尺度能更好地解释整体水质变化，而土地利用影响水质的空间尺度也因具体水质参数和地貌基础而异。本研究表明，流域管理应采取更好的景观规划和多尺度措施来改善水质。
