基于中介效应模型的流域土地利用变化对杞麓湖富营养化的影响

Effects of Land Use Change on Eutrophication of Qilu Lake Based on Mediation Effect Model

研究土地利用变化对湖泊水体富营养化的影响并明确中间的传导要素和贡献对揭示湖泊富营养化成因及其防控具有重要意义。基于杞麓湖流域2005~2015年土地利用与湖泊富营养化数据,运用综合营养状态指数、Mann-Kendall检验、中介效应模型研究了杞麓湖富营养化变化及其受土地利用变化的影响路径和效应。结果表明,杞麓湖富营养化逐渐加重,2013年达到重度富营养化程度,流域土地利用变化明显,显著加剧了湖泊富营养化程度;耕地变化通过化肥使用量影响Chl.a、TN、COD_(Mn)三者浓度及SD变化,具有明显的中介效应;建设用地变化通过污染物排放量影响Chl.a、COD_(Mn)的浓度变化及SD变化,具有明显的中介效应;林地、草地、水域面积变化分别通过植物覆盖度、家禽出栏量、水位影响湖泊富营养化变化。

Researching the impact of land use change on lake eutrophication and determining the mediating impact factors and contribution are greatly significant to provide decision-making for prevention and control lake eutrophication.This paper assessed the eutrophication change of Qilu Lake and the effects path and effect of land use by employing the comprehensive nutritional status index,the Mann-Kendall analysis and mediating effect model with the land use and lake eutrophication data of Qilu Lake from 2005 to 2015.The results show that the lake eutrophication aggravated gradually and reached the severe degree eutrophication in 2013.There were significant changes in land use in Qilu Lake basin,which exacerbated the lake eutrophication significantly.The concentration of Chl.a,TN and COD_(Mn) and the change of SD were affected by the change of cultivated land through the utilizations of chemical fertilizer,which had a significant mediating effect.The concentration of Chl.a,COD_(Mn) and the change of SD were affected by the change of construction land through the pollutant emission,the mediating effects are distinct similarly.The changes of forest land,grassland,water area affect the changes of lake eutrophication through plant coverage,poultry slaughter,water level respectively.