滨岸带对河流生态系统的影响机制研究进展

Review on the influence mechanism of riparian zone to the river ecosystem

从水文调节、水质改善、物质输入调控、生物多样性维持等方面梳理了滨岸带对河流生态系统的影响机制。滨岸带具有良好的水文调节效应,这种调节效应主要通过滨岸带植被根系对土壤水分持留,植物残体对径流路径的影响,以及挺水和沉水植物对水流的物理作用等途径实现。滨岸带显著影响水质过程,对于面源污染径流具有较好的净化效果。滨岸带能够经历周期性的干湿交替,同时具有发达的植被系统和丰富的土壤微生物类型,独特的水文和地球化学条件使滨岸带成为氮磷迁移转化的热区。滨岸带对水生态系统的物质输入起到重要的调控作用,既能够为水体生态系统提供丰富的物质来源,又能够避免过量的营养物质输入。这种调控作用对于水生态系统群落结构的维持和生态系统功能的发挥具有重要意义。滨岸带水生和湿生植被的生长使水体生态系统食物链不断完善,大型无脊椎生物和鱼类种群数量得以增加,对水体生物多样性的提升具有明显的贡献。自然的洪水扰动可能是滨岸带生物多样性的维持机制,而水媒传播过程则可能是滨岸带影响河流生物多样性的重要机制。当前对于滨岸带生态机制过程的认识尚不够深入,今后滨岸带研究要加强物质过程和生态学过程的探讨,尤其是水文、水质、生物群落等要素的耦合机制,滨岸带水环境效应的模拟预测,以及滨岸带对河流生物多样性的影响机制研究等。

The influence mechanism for riparian zone to the river ecosystem is reviewed from the aspects of hydrologic regulation,water quality improvement,material input controlling and biodiversity maintenance.The results show that riparian zone has a significant effect on hydrologic regulation,which is mainly achieved through increasing the water holding capacity of soil,changing the surface runoff path,weakening the erosion strength,and redistributing flow velocities or flow field characteristics by the emergent plants and submerged plants.Besides,the riparian zone can experience cyclical dry-wet alternate,and simultaneously has the rich vegetation and rich soil microbial types.These unique hydrological and geochemical conditions make riparian zone act as the ＂hot spots＂ for migration and transformation of nitrogen and phosphorus.The riparian zone is also indispensable for maintaining the structure and function of the aquatic ecosystem.It can both supply abundant materials for the water body and simultaneously avoid excessive loads of nutrients or other pollutants.This kind of regulation plays an important role in the maintenance of structure as well as function of the aquatic ecosystem.Finally,the riparian zone plays a key role in preserving the biodiversity of aquatic ecosystems.The growth of aquatic and wet vegetation complete the food chain of the aquatic ecosystem,and increase the number of large invertebrates and fish populations,which contribute obviously for the promotion of the aquatic biodiversity.The flood disturbance and hydrochory can be recognized as the key factors affecting or driving these processes.Until now,the understanding to the ecological processes in the riparian zone is not sufficiently deep.The future study should focus on the material and ecological processes,especially 1）the coupling mechanism among hydrological and biological factors in the riparian zone,2）simulation and prediction of the water quality effect of the riparian zone,and 3）the influencing mechanism of the riparian zone to the river biodiversity.