Graduate Program, Department of Forestry and Landscape Architecture, Konkuk University, Gwangjin-Gu, Seoul 05029, Korea.
Department of Forestry and Landscape Architecture, Konkuk University, Gwangjin-Gu, Seoul 05029, Korea.
Int J Environ Res Public Health. 2020 Mar 23;17(6):2116. doi: 10.3390/ijerph17062116.
The extent of anthropogenic land use in watersheds determines the amount of pollutants discharged to streams. This indirectly and directly affects stream water quality and biological health. Most studies have therefore focused on ways to reduce non-point pollution sources to streams from the surrounding land use in watersheds. However, the mechanistic pathways between land use and the deterioration of stream water quality and biological assemblages remain unclear. This study estimated a structural equation model (SEM) representing the impact of agricultural and urban land use on water quality and the benthic macroinvertebrate index (BMI) using IBM AMOS in the Nam-Han river systems, South Korea. The estimated SEM showed that the percent of urban and agricultural land in the watersheds significantly affected both the water quality and the BMI of the streams. Specifically, a higher percent of urban land use had directly increased the biochemical oxygen demand (BOD) and total phosphorus (TP), and deteriorated the BMI of streams. Similarly, higher proportions of agricultural land use had also directly increased the BOD, total nitrogen (TN), and total phosphorus (TP) concentrations, and lowered the BMI of streams. In addition, it was observed that the percent of urban and agricultural land use had indirectly deteriorated the BMI through increased BOD. However, we were not able to observe any significant indirect effect of the percent of urban and agricultural land use through increased nutrients including TN and TP. These results indicate that increased urban and agricultural land use in the watersheds had directly and indirectly affected the physicochemical characteristics and benthic macroinvertebrate communities in streams. Our findings emphasize the need to develop more elaborate environmental management and restoration strategies to improve the water quality and biological status of streams.
流域内人为土地利用的程度决定了排放到溪流中的污染物的数量。这间接和直接影响了溪流的水质和生物健康。因此，大多数研究都集中在如何减少流域内周围土地利用对溪流的非点源污染。然而，土地利用与溪流水质和底栖大型无脊椎动物生物组合恶化之间的机制途径仍不清楚。本研究使用 IBM AMOS 在韩国南汉河流域估计了一个结构方程模型 (SEM)，代表农业和城市土地利用对水质和底栖大型无脊椎动物指数 (BMI) 的影响。估计的 SEM 表明，流域内城市和农业用地的百分比显着影响了溪流的水质和 BMI。具体而言，较高的城市土地利用比例直接增加了生化需氧量 (BOD) 和总磷 (TP)，并恶化了溪流的 BMI。同样，农业用地比例的增加也直接增加了 BOD、总氮 (TN) 和总磷 (TP) 浓度，并降低了溪流的 BMI。此外，还观察到城市和农业土地利用比例通过增加 BOD 间接恶化了 BMI。然而，我们没有观察到城市和农业土地利用比例通过增加包括 TN 和 TP 在内的养分对 BMI 的任何显着间接影响。这些结果表明，流域内城市和农业土地利用的增加直接和间接影响了溪流的理化特性和底栖大型无脊椎动物群落。我们的研究结果强调需要制定更精细的环境管理和恢复策略，以改善溪流的水质和生物状况。
