Programa de Pós-Graduação em Ecologia, Universidade Federal do Rio Grande do Norte, Natal, RN, Brazil.
Programa de Pós-Graduação em Ecologia, Universidade Federal do Rio Grande do Norte, Natal, RN, Brazil; Departamento de Ecologia, Universidade Federal do Rio Grande do Norte, Natal, RN 59078-900, Brazil.
Sci Total Environ. 2020 May 10;716:137044. doi: 10.1016/j.scitotenv.2020.137044. Epub 2020 Jan 31.
Globally, conversion of pristine areas to anthropogenic landscapes is one of the main causes of ecosystem service losses. Land uses associated with urbanization and farming can be major sources of pollution to freshwaters promoting artificial inputs of several elements, leading to impaired water quality. However, how the effects of land use on freshwater quality are contingent on properties of the local landscape and climate is still poorly understood. The aim of this study was to evaluate the effects of landscape properties (morphometric measurements of lakes and their catchments), precipitation patterns, and land use properties (extent and proximity of the land use to freshwaters) on water quality of 98 natural lakes and reservoirs in northeast Brazil. Water quality impairment (WQI) was expressed as a composite variable incorporating parameters correlated with eutrophication including nitrogen (N), phosphorus (P) and Chlorophyll-a concentration. Regression tree analysis showed that WQI is mainly related to highly impacted "buffer areas". However, the effects of land use in these adjacent lands were contingent on precipitation variability for 13% of waterbodies and on surface area of the buffer in relation to the volume of waterbody (BA:Vol) for 87% of waterbodies. Overall, effects on WQI originating from the land use in the adjacent portion of the lake were amplified by high precipitation variability for ecosystems with highly impacted buffer areas and by high BA:Vol for ecosystems with less impacted buffer areas, indicating that ecosystems subjected to intense episodic rainfall events (e.g. storms) and higher buffer areas relative to aquatic ecosystem size (i.e. small waterbodies) are more susceptible to impacts of land use. Land use at the catchment scale was important for the largest ecosystems. Thus, our findings point toward the need for considering a holistic approach to managing water quality, which includes watershed management within the context of climate change.
在全球范围内，原始区域向人为景观的转化是生态系统服务丧失的主要原因之一。与城市化和农业相关的土地利用可能是淡水污染的主要来源，促进了多种元素的人工输入，导致水质受损。然而，土地利用对淡水水质的影响如何取决于当地景观和气候的特性，这仍然知之甚少。本研究的目的是评估景观特性（湖泊及其集水区的形态计量测量）、降水模式和土地利用特性（土地利用的范围和与淡水的接近程度）对巴西东北部 98 个天然湖泊和水库水质的影响。水质受损指数（WQI）表示为一个综合变量，包含与富营养化相关的参数，包括氮（N）、磷（P）和叶绿素-a 浓度。回归树分析表明，WQI 主要与受影响较大的“缓冲区”有关。然而，这些相邻土地上的土地利用的影响取决于 13%的水体的降水变异性，以及缓冲区的表面积与水体体积（BA:Vol）的关系，对于 87%的水体而言。总体而言，来自湖泊相邻部分的土地利用对 WQI 的影响，在受缓冲区高度影响的生态系统中，由于高降水变异性而放大，在受缓冲区影响较小的生态系统中，由于高 BA:Vol 而放大，这表明，受强烈阵发降水事件（如风暴）影响且缓冲区相对于水生生态系统大小（即小水体）较高的生态系统更容易受到土地利用的影响。集水区尺度上的土地利用对最大的生态系统很重要。因此，我们的研究结果表明，需要考虑一种综合方法来管理水质，其中包括在气候变化背景下进行流域管理。
