河岸植被缓冲带作为河岸生态系统的重要组成部分,是控制水土流失和面源污染、改善水环境的关键措施,对河岸生态系统的生态及水文过程具有重要的影响。概述了国内外关于河岸植被缓冲带研究的现状,总结了河岸植被缓冲带的主要功能、影响其功能发挥的主要因素和作用机理,并对河岸植被缓冲带的设计、管理和效益评估进行阐述,提出了我国在未来关于河岸植被缓冲带研究的发展趋势及后续研究中仍需加强和关注的重要方向,为今后河岸植被缓冲带的研究提供参考和借鉴,具有一定的理论价值和实际意义。

As an important component of riparian ecosystem, riparian vegetative buffer strip is a key measure to control water and soil loss and non-point source pollution and to improve water environment. And it has an important influence on the ecological and hydrological processes of riparian ecosystem. In this article, the research status of riparian vegetative buffer strip in China and abroad is reviewed and the main functions, main factors and mechanism affecting its functional performance are summarized. Moreover, the design, management and benefit evaluation of the riparian vegetative buffer strip are expounded. The development trend of researches on riparian vegetative buffer strip in the future and the important directions which need focuses are also put forward. This article could provide reference and draw lesson for future researches on riparian vegetative buffer strip and have theoretical value and practical significance.

开展丹江口水库消落带土壤总氮(TN)和总磷(TP)变化特征与通量研究,对明晰消落带污染输出特征、保护水库水质安全有着重要的实践作用。将丹江口水库划分为汉库和丹库两个区域,以不同区域内典型消落带为研究对象,监测分析了2020年9月—2021年9月不同时期不同区域消落带土壤TN和TP的变化特征,并通过收支平衡法构建模型,估算了丹江口水库消落带在不同时期的TN和TP通量。结果表明,2020年9—12月淹水期内,丹江口水库不同区域消落带TN、TP含量变化显著,汉库耕地和园地的TN、TP含量显著上升,其余区域消落带土壤均存在TN、TP流失现象。2021年3—6月落干期内,丹江口水库不同区域消落带TN、TP含量总体上呈现上升积累趋势。2020年9月—2021年9月,丹江口水库不同区域消落带TN、TP含量整体呈下降趋势。丹江口水库消落带在淹水期表现为氮和磷的释放源,TN通量834.66 t,TP通量10 422.12 t;在落干期表现为氮和磷的吸收汇,TN通量-8 623.69 t,TP通量-10 032.94 t。2020年9月—2021年9月,丹江口水库消落带总体上表现为氮和磷的释放源,TN通量20 122.22 t,TP通量1 509.52 t。丹江口水库消落带污染物释放对水库水质安全的风险不容忽视。

三峡水库蓄水后水位季节性波动给消落带带来了极大的环境胁迫。如何进行消落带生态系统修复,优化其生态系统服务功能,基于自然的解决方案是解决消落带复杂环境问题的重要途径。以位于三峡库区的澎溪河流域消落带为例,在阐述消落带生态系统修复设计策略和技术框架的基础上,结合持续10余年的消落带生态系统修复实践,分析了植物物种筛选及种源库建立、近自然植物群落构建、多功能基塘修复、复合林泽修复、多维湿地修复、地形-底质-植物-动物协同修复等技术的综合应用及其成效。结果表明,所筛选的植物耐淹性能及存活状况良好,修复后的消落带植物群落结构稳定,生物多样性提升、面源污染削减效果明显。澎溪河流域消落带生态系统修复实践解决了大幅度水位变化和冬季深水淹没的三峡水库消落带生态修复难题,创新性地构建了水库消落带生态系统修复技术体系,为大型湖库消落带生态修复提供了可推广、可复制的技术方法及实践模式。

The seasonal fluctuation of water level after the impoundment of the Three Gorges Reservoir has brought great environmental stress to the water level fluctuating zone. How to restore the water level fluctuating zone and optimize its ecosystem service function? Nature-based solution is an important approach. In this paper, the design strategy and technical framework of ecosystem restoration for the water level fluctuating zone of Pengxi River Basin in the Three Gorges Reservoir Area were expounded as a case study. In line with over a decade of practice in ecosystem restoration of water level fluctuating zone, the comprehensive application and effectiveness of nature-based technologies were analyzed. Such technologies include: the selection of flood resistant plant species, the establishment of plant provenance bank, the construction of near-natural plant community, multi-functional dike ponds, wetland woods complexity, multi-dimensional wetlands and collaborative restoration technology involving terrain,sediment,plants and animals in the fluctuating zone. The results manifested that the selected plants had good flood resistance and survival status, plant community structure in the restored fluctuating zone was stable, biodiversity was improved and non-point source pollution was reduced significantly. The nature-based practice of ecosystem restoration in Pengxi River Basin has solved the problem caused by large-amplitude water level change and deep-water inundation in winter, and creatively constructed a technical system of ecosystem restoration in the water level fluctuating zone of reservoir. The research findings offer a popularized and reproducible technical method and practical model for the ecological restoration of fluctuating zone of large lakes and reservoirs.

地瓜藤(Ficus tikoua)、荻(Triarrhena sacchariflora)、牛鞭草(Hemarthria altissima)和狗牙根(Cynodon dactylon)是三峡库区常见的岸生植物, 自然分布于河岸带不同垂直高程的地段。为了明确它们在成库后“三峡库区消落区”长期完全水淹条件下的存活和生长情况, 实验设置对照(不进行水淹, 常规供水管理)和完全水淹两个处理, 30、60、90、120、150和180 d 6个水淹时间水平, 研究了4种植物在完全水淹条件下的存活、生物量变化和恢复生长。结果发现: 1) 4种植物在完全水淹条件下的存活率与其在河岸带上的垂直分布高程密切相关。分布于距江面高程较高的河岸段的地瓜藤植株, 在全淹30 d后就全部死亡; 分布在中高程河岸段的荻在全淹150和180 d后全部死亡; 可以分布于低高程河岸段的牛鞭草和狗牙根, 淹没180 d后存活率分别为90%和100%。2)全淹抑制了荻、牛鞭草和狗牙根的生长, 总生物量增量显著低于对照植株。与水淹0 d相比, 全淹处理植株的地上部分生物量显著降低, 荻在全淹60和120 d后, 地下部分生物量显著降低, 但牛鞭草和狗牙根的地下部分生物量与水淹0 d水平相比无显著差异。3)水淹处理结束后, 存活的荻、牛鞭草和狗牙根植株都能很好地恢复生长。在恢复生长过程中, 全淹30、60和90 d后, 荻、牛鞭草和狗牙根植株的总分枝长相对生长速率与对照植株无显著差异, 全淹120、150和180 d后, 牛鞭草和狗牙根植株的总分枝长相对生长速率显著高于对照植株。全淹处理的荻、牛鞭草和狗牙根植株的总叶片数相对生长速率始终显著高于对照植株。遭受长期完全水淹后, 植株在有限的营养储备条件下, 快速产生叶片以迅速积聚光合产物可能是植物更为优化的恢复生长方式。

干热河谷库区消落带生态修复关键技术难点在于当消落带植被受到长时间淹水与干旱交替双重胁迫时,如何遴选生态修复两栖植物。通过对乌东德库区消落带生态修复试验段淹没前植被调查、溪洛渡库区和三峡库区典型库岸消落带现存植物种群调查以及查阅三峡库区消落带植被自然演替和植被修复相关文献,结合乌东德水电站水位调度节律和库区干热河谷气候条件,对乌东德库区消落带植被自然演替趋势进行了分析。按照自然修复与人工修复相结合、乡土植物与外来植物相结合的消落带生态修复理念,遴选出乌东德库区消落带生态修复试验植物,提出了在试验段沿海拔高程的植物梯度配置模式:消落带中下部配置以狗牙根、香附子、扁穗牛鞭草等为主的多年生草本植物和以苘麻、狗尾草、马唐等为主的一年生草本植物;消落带上部配置以中山杉、水桦、桑树、秋华柳、银合欢等为主的乔、灌木以及草本植物。

The key technical difficulty of ecological restoration in dry-hot valley reservoirs lies in screening plants with strong flooding and drought tolerance. We present the potential tendency of plant community succession in water-level-fluctuating zone of Wudongde reservoir area based on vegetation investigations in Wudongde, Xiluodu and Three Gorges reservoir areas as well as related researches, climatic conditions and water fluctuation rhythm. In consideration of natural and artificial restoration, native and exotic plants, we selected the plants for ecological restoration in water-level fluctuating zone of Wudongde reservoir area, and propose the vegetation arrangement along altitude gradient. The middle and lower altitudes of water-level fluctuating zone are equipped with herbs inclusive of <i>Cynodon dactylon</i>, <i>Cyperus rotundus</i>, <i>Hemarthria altissima</i>, <i>Abutilon theophrasti</i>, <i>Setaria glauca</i> and <i>Digitaria sanguinalis</i>, and the upper is arranged with trees including <i>Albizia julibrissin</i>, <i>Taxodium‘Zhongshanshan'</i>, <i>Betula nigra</i>, <i>Morus alba</i> and <i>Salix variegates</i>, and a quantity of herbaceous plants.