南宁市湖库型饮用水源景观结构与涵养功能关系耦合优化

为探明湖库型饮用水源景观结构与涵养功能间的内在机理,优化水源涵养林功能,保护水源安全,借助遥感解译技术得到各用地类型面积并计算水源涵养功能指数,依据取水量和水源涵养量间水量平衡模式计算所需最小森林面积,应用多元数量分析方法探究水源涵养功能指数、景观格局指数、水质指标之间的耦合关系。结果表明:(1)水源地3 km缓冲区较500 m缓冲区的水源涵养功能有所下降。(2)用最小面积法优化筛选出以软阔叶林、栎林、硬阔叶林、竹林为主的岸边带森林生态系统可有效提高水源涵养功能,最大限度的满足饮用水源保护区面积、集雨区面积和涵养区面积间的数量关系。(3)水源涵养功能与景观格局、水资源、水质和污染物排放间可建立起通过显著性检验的多元回归拟合模型方程。(4)多维尺度综合分析过程可诊断出南宁市湖库型饮用水源在生态系统稳定性、水资源量和水质方面存在的生态安全与风险隐患问题,建议南宁市开展饮用水源环境综合整治、生态系统保护与修复工作。

Coupling relationship optimization of landscape structure and conservation function of lake and reservoir drinking water sources in Nanning, China

To analyze the internal mechanism between landscape structure and conservation function of lake and reservoir drinking water sources, optimize forest water conservation, and protect water sources, land use/cover information was first obtained on the basis of satellite remote sensing interpretation to calculate the water conservation function index. Later, according to the balance between water withdrawal and conservation, minimum required forest areas of different specific forest types for each reservoir drinking water source were estimated. Finally, multi-dimensional analysis methods were adopted to evaluate the relationships among the water conservation function index, landscape ecological indices, and water quality of the reservoir drinking water sources. The results showed that:(1) the water source conservation function of the 3 km buffer zone of the reservoirs is slightly lower than that of the 500 m buffer zone. (2) Screen riparian forest ecosystems dominated by soft broad-leaved forests, oak forests, hard broad-leaved forests, and bamboo effectively improve the capability of water conservation, meet the requirement of the quantitative relationship and functions of drinking water conservation, rain collection, and protection areas delineating. (3) Regression model equations can be established using the water conservation function index, landscape pattern indices, water resources, water quality, and pollutant discharge. (4) The comprehensive multi-dimensional scale analysis can evaluate the ecological safety and risks of ecosystem stability and water resource quantity and quality of Nanning lake and reservoir drinking water sources. We recommend Nanning City to conduct comprehensive programs and improve the drinking water source environment and ecological system protection and restoration.