摘要
为揭示土地利用结构与空间格局对中小河流水质的影响机制,于2022年1月与2022年7月在鄱阳湖流域3条中小河流的25个采样点收集水样.采用Bioenv分析、Mantel检验与方差分解量化不同空间尺度的土地利用结构与空间格局对水质的影响,使用广义加性模型拟合水质与土地利用结构与空间格局的关系,广义线性模型构建分段回归模型,并基于逐步递归法计算阈值.结果表明:(1)土地利用结构与空间格局对河流水质的平均解释率在丰水期(59.72%)大于枯水期(48.95%);子流域与河岸100 m是土地利用结构与空间格局影响中小河流水质的关键尺度,平均解释率分别为54.70%和64.88%;土地利用结构与空间格局的共同解释部分是驱动河流水质变化的重要因素,占总解释率的66.90%.(2)土地利用结构对中小河流水质的影响具有显著的阈值效应,当子流域尺度下建设用地占比低于2%、耕地占比低于8%和林地占比高于82%,河岸缓冲区尺度下建设用地占比低于12%、耕地占比低于41%和林地占比高于49%时,均能明显改善水质.(3)空间格局对中小河流水质的影响也具有阈值效应但弱于土地利用结构,当子流域尺度下斑块形状值大于28.77和斑块多样性大于0.69,河岸缓冲区尺度下斑块形状值大于2.99和斑块多样性大于1.02时,均能改善水质.以上结果表明,加强对子流域与河岸100 m尺度的土地利用的管理,合理规划土地利用结构与空间格局能够有效地防止水质恶化.
To reveal the influence mechanism of land use structure and spatial pattern on water quality of small and medium-sized rivers,water samples were collected from 25 sampling points in three small and medium-sized rivers of the Poyang Lake Basin in January 2022 and July 2022.Bioenv analysis,the Mantel test,and variance partitioning analysis were used to quantify the effects of land use structure and spatial patterns on water quality at different spatial scales;generalized additive models were used to fit the relationship between water quality and different land use structures and spatial patterns;and a generalized linear model was used to construct segmented regression models and calculate the thresholds based on the stepwise recursive method.The results showed that:①the average interpretation rate of land use structure and spatial pattern on river water quality was 59.72% during the wet period and 48.95% during the dry period.The sub-basin and riparian 100 m scales were the key scales of land use structure and spatial pattern affecting water quality in small and medium-sized rivers,with an average explanation rate of 54.70%and 64.88%,respectively.The joint explanation of land use structure and spatial pattern was an important factor driving the change in river water quality,accounting for 66.90% of the total explanation.②The impact of land use structure on the water quality of small and medium-sized rivers had a significant threshold effect.When the proportion of construction land was less than 2%,farmland was less than 8%,or forest land was more than 82% at the sub-basin scale and the proportion of construction land was less than 12%,farmland was less than 41%,or forest land was more than 49% at the riparian buffer scale,all could significantly improve water quality.③The effect of spatial pattern on water quality in small and medium-sized rivers also had a threshold effect but was weaker than that of land use structure.A patch shape value more than 28.77 or patch diversity more than 0.69 at the sub-basin sca
作者
温嘉伟
王鹏
黄高翔
张华
聂明华
丁明军
折远洋
WEN Jia-wei;WANG Peng;HUANG Gao-xiang;ZHANG Hua;NIE Ming-hua;DING Ming-jun;SHE Yuan-yang(School of Geography and Environment,Jiangxi Normal University,Nanchang 330022,China;Key Laboratory of Poyang Lake Wetland and Watershed Research,Ministry of Education,Jiangxi Normal University,Nanchang 330022,China)
出处
《环境科学》
EI
CAS
CSCD
北大核心
2023年第12期6728-6743,共16页
Environmental Science
基金
国家自然科学基金项目(42167013)。
关键词
鄱阳湖流域
土地利用结构
空间格局
空间尺度
阈值效应
Poyang Lake Basin
land use structure
spatial pattern
spatial scale
threshold effect
