湿地农田渠系的生态环境影响研究综述

天然湿地开垦为农田，排水渠系扩张，随之带来两个方面的生态环境影响。作为廊道，排水渠系的隔离作用割裂了景观，造成湿地景观破碎化，甚至景观性质的改变；同时，其通道作用影响了湿地的水文过程，将局部湿地排干而转变为农田，并成为农田污染物向受纳河流水体运移的快速通道。因此，根据排水渠系的功能特点，在局域和区域两个层次上，对其生态环境影响开展综合研究，可以为湿地保护和恢复提供切实可行的对策措施。在回顾相关研究的基础上，提出了排水渠系生态环境影响研究的一个思路：即基于景观生态学和生态学模型等，开展排水渠系生态环境影响的机制研究；基于环境影响评价和生态系统健康评价等，开展排水渠系生态环境影响的效应研究；以及基于恢复生态学等，开展排水渠系的生态调控对策措施研究，从而为排水渠系的生态环境影响研究提供系统性途径。

A review on the ecological and environmental impacts of agricultural ditch systems in wetlands

In the process of wetlands exploitation, agricultural ditch systems are widespread and cause ecological and environmental impacts on landscape in two ways. On the one hand, as corridors, ditch systems have the function to separate a landscape, lead to landscape fragmentation, and even alter wetlands into farmlands dominated landscape. On the other hand, as pathways, ditch systems change the hydrologic processes of the region and provide a shortcut for the spatial movement of agricultural pollutants from farmlands to rivers. According to the two functions of ditch systems, an investigation on its ecological and environmental impacts at local and regional scales will provide feasible measures for wetland protection and rehabilitation. Based on a review on previous studies, a systematic approach is put forward to deal with the ecological and environmental impacts of agricultural ditch systems: 1) its mechanisms should be detected with landscape ecology and ecological modeling; 2) its impacts should be traced by environmental impact assessment and ecosystem health evaluation; and 3) its ecological control should be realized through the means of restoration ecology. This integrated solution will provide a new way for studying the ecological and environmental impacts of agricultural ditch systems in wetlands.