亚热带高原岩溶区陆地植被-湖泊湿地间的水文协同效应观测研究

The most prominent phenomenon of land cover change response to climate change and human activities is the disappearance of vegetation and wetland. Does the ecosystem reconstruction correspond to the synergistic restoration of such vegetation with lake wetlands? The project proposed the hypothesis that existence of synergistic effect of hydrological between terrestrial vegetation and lake wetland in karst area of in the subtropical plateau: suitable vegetation helps to keep the lake level, and the lake promote the of vegetation succession. Paired catchment experiment and measurement principle based on the set of natural and secondary, rocky desertification vegetation with lake wetland are designed, vegetation hydrological-lake hydrological processes and vegetation community paired observation and sampling analysis are carried out. Test areas are Guan Shan reservoir, Chang Lake and Moon lake watershed in Shilin County of Yunnan province. In order to obtain the water balance of lake wetland with rainfall, infiltration, soil water, surface runoff, karst belt water and karst springs, the lake evaporation, rainfall and vegetation vertical structure and horizontal structure layer distribution of rainfall are observed, and investigation couple with analysis of vegetation community at the same time. From the aspect of water balance and the water source, the biodiversity restoration and renewal of community to get the synergy between vegetation and lake wetland. In this study, the mechanism of hydrology synergetic effect between terrestrial vegetation and lake wetland is expounded, and the protection and restoration technology of ecological restoration and sustainable water supply in karst area are constructed.

陆表土地覆被对气候变化与人类活动响应最突出的现象是植被、湖泊湿地的同步消失。生态系统重建是否对应这样的植被与湖泊湿地的协同恢复？项目基于亚热带高原岩溶区陆地植被-湖泊湿地间存在水文协同效应的研究假设：适宜的陆地植被有助于湖泊湿地水位保持，而稳定的湖泊湿地促进陆地植被生物多样性与正向演替。依据配对汇水区实验和过程测量原理，设置原生、次生、石漠化植被和湖泊湿地的植被水文-湖泊水文过程配对观测。试验地为滇中石林县官山水库、长湖和月湖小流域。开展湖泊蒸发、降水与植被垂直结构层和水平结构的降水分配观测，以获取实验区降水、入渗、土壤水、地表径流、表层岩溶带水和岩溶泉与湖泊湿地的水平衡关系，同步进行植被影像分析与群落调查，从水量与水分来源、植被分布格局、生物多样性与群落更新角度获取植被与湖泊湿地的协同性，揭示陆地植被-湖泊湿地间的水文协同机制，构建促进岩溶区生态恢复与水资源持续供给的理论基础与技术途径。

退化岩溶区石漠化与水资源环境问题是全球水文地质研究中的关键问题之一，是区域可持续发展的严重制约因素，中国西南岩溶区尤为突出，气候变化及人类活动加剧了我国西南岩溶区石漠化趋势和水资源短缺。土地生产力下降、地表植被覆盖率锐减、水源地产水层瓦解及地表水资源枯竭，成为我国西南岩溶区的基本形态。本研究以滇中岩溶高原区石林彝族自治县典型陆地植被-湖泊湿地试验样地为重点研究区，通过水文观测、植被群落调查与对比、稳定同位素示踪并联合“3S”技术，探讨陆地植被与湖泊湿地间的水文协同机制，尝试构建促进岩溶区生态恢复与水资源持续供给的陆地植被-湖泊湿地格局的保护与修复技术。项目取得了以下认识：首先，对密枝林、次生林和云南松林等陆地植被与坡耕地、石漠化灌草丛的观测结果表明，适宜的陆地植被能调蓄降水，实现表层岩溶带垂直结构层对降水的再次分配，水平分布格局则能有效汇聚降水，补充土壤水和表层带岩溶水，减少对地下水的消耗，减少地表径流并缓慢释放，从而保持湖泊湿地的水位，有助于维护湖泊湿地的稳定；其次，从长湖、月湖、官山水库观测得知，湖泊湿地通过水汽再循环增加附近空气的水汽含量，在有利地形、风向、风力与适配陆地植被配合下，激发了局地降水，尤其在干旱缺水的季节，湖泊湿地通过水汽再循环的蒸发、降水环节与地下水水位维持，增加空气湿度并调节土壤水分，有利于陆地植被生物多样性维持并促进其向地带性植被群落正向恢复演替；最后，确认了面积适宜、位置适当、植物类型适合的适配的陆地植被格局对表层带产流和局地降水过程具有水分调节功能，而湖泊湿地的存在则对周边植被的维持有促进作用，故在岩溶区水源地建设、植被恢复过程中应将两者同步开展。总之，项目成果不仅有助于深化对岩溶区生态水文循环规律的认识，还可为岩溶石漠化区生态治理与水源地建设提供科学依据。