Song Jing-Wen, Zhang Xue-Xia, Jiang Dong-Yang, Zhao Cheng-Hao, Li Peng-Fei
School of Soil and Water Conservation, Beijing Forestry University, Beijing 100083, China.
Key Laboratory Soil and Water Conservation National Forestry and Grassland Administration Beijing 100083, China.
Huan Jing Ke Xue. 2022 Jun 8;43(6):3016-3026. doi: 10.13227/j.hjkx.202108234.
As an important carrier of human activities, the spatial type of land use has an important impact on the surface water environment. Taking the Ruoergai wetland as an example, based on object-oriented remote sensing interpretation of land use types combined with water quality examination data, this study analyzed the impact and driving mechanism of land use types at different scales on the surface water environment at the small watershed and buffer scale. ① It was found that the water quality of the Ruoergai wetland could been classified as water grade V, and it was slightly eutrophic as a whole. The main pollutants were total nitrogen(TN) and phosphorus(TP), and the pollution originated from domestic sewage and grazing. ② The environmental quality of surface water was closely related to land use types. There was a negative correlation between chemical oxygen demand(COD) and the proportion of water area, a positive correlation between TN and the proportion of swamp area, and a negative correlation between total TP. ③ There was a significant correlation between spatial land use types at different scales and surface water environment. The land use type within a buffer of 1000 m had the highest interpretation degree for all factors, the land use type within a buffer of 200 m had the greatest interpretation degree for COD, the land use type within a buffer of 500 m zone had the greatest interpretation degree for TP and TN, and the land use type within a buffer of 800 m had the greatest explanation for Chl-a. The results of this study showed that the Ruoergai wetland wetland had a certain purification effect on pollutants and eutrophication. However, different land use types had different effects on different pollutants. The water body had a purification effect on Fe, COD, and Chl-a, and the swamp had a purification effect on TP but a cumulative effect on TN. Thus, the small-buffer zone(≤ 1000 m) land use type should be controlled, the water body and swamp areas should be controlled, the self-purification capacity of wetland waters should be improved, and the surface water environment of the Ruoergai wetland should be further protected and repaired.
作为人类活动的重要载体，土地利用的空间类型对地表水环境有着重要影响。以若尔盖湿地为例，基于土地利用类型的面向对象遥感解译并结合水质检测数据，本研究分析了不同尺度的土地利用类型对小流域和缓冲区尺度地表水环境的影响及驱动机制。①研究发现，若尔盖湿地水质可划分为Ⅴ类水，整体呈轻度富营养化。主要污染物为总氮（TN）和总磷（TP），污染源于生活污水和放牧。②地表水的环境质量与土地利用类型密切相关。化学需氧量（COD）与水域面积比例呈负相关，TN与沼泽面积比例呈正相关，总磷（TP）与之呈负相关。③不同尺度的空间土地利用类型与地表水环境存在显著相关性。1000米缓冲区内的土地利用类型对所有因子的解释度最高，200米缓冲区内的土地利用类型对COD的解释度最大，500米缓冲区内的土地利用类型对TP和TN的解释度最大，800米缓冲区内的土地利用类型对叶绿素a（Chl-a）的解释度最大。本研究结果表明，若尔盖湿地对污染物和富营养化有一定的净化作用。然而，不同土地利用类型对不同污染物的影响不同。水体对铁、COD和Chl-a有净化作用，沼泽对TP有净化作用，但对TN有累积作用。因此，应控制小缓冲区（≤1000米）的土地利用类型，管控水体和沼泽区域，提高湿地水体的自净能力，进一步保护和修复若尔盖湿地的地表水环境。
