Ecological Effect Of Main Restoration Measures In Two Distinctive Streams

Worldwide, stream and river ecosystems are threatened by human activities. Stream ecosystem restoration gradually attracted widespread attentions in recent years. This study choosed a rural stream and a urban stream as research subjects to design for each stream damaged characteristics, to implement restoration projects, and to monitor the restorative effects. This study focused on major stress factors of stream ecosystems to explore the restoration programs for two distinctive streams, and to assess the ecological effect of main restoration measures. The results have scientific significance and application value to guide small and medium-sized damaged stream ecological restorations.We obtained the main results and conclusions as follows.1) The main stress factors were obviously different between rural stream and urban stream. The primary stress factor in urban stream in developing countries was water pollution caused by the industrial wastewater and domestic sewage. With the deterioration of water quality, there was an overall decrease in the species number of macroinvertebrates, a reduction of the biodiversity, and a reduction of functional feeding groups. Finally, the urban stream only worked for receiving sewage and flood carrying capacity. The primary stress factors for rural stream were the degradation of a habitat, the decrease of stream flow, and water pollution caused by agricultural activity.2) The primary task was to stabilize riverbanks and intercept soil loss in rural stream restoration engineering. In-stream restoration measures obviously improved stream habitat. The ecological effects of different restoration measures(wetlands in-stream, hydraulic drops, ripraps in-stream, or groins) complemented each other, no better or worse between the measures. Repair works to protect riparian stability, riparian vegetation construction, water purification, and physical habitat improvement measures were must-haves for rural stream restoration.3) For damaged rural stream in northern China, the combination of the restoration of meandering shape, build of composite ecological revetment, build of wetland in-stream in the upper reaches, intermittent hydraulic drops, and the ripraps in-stream in straight stream channel was effective.4) Water quality control was a prerequisite for urban stream restoration. The effectiveness of ecological restoration measures in highly polluted streams was very limited. In urban stream restoration process, the ecological restoration measures in-stream were not sufficient to improve the habitat conditions. In developing countries, in the context of limited funds, more funds should be used for water quality control and repair.In this study, long-term monitoring data were used to assess the ecological effect of main restoration measures. Because the designer of the monitoring experiment directly involved in the design and implementation of the stream restoration projects, our study results had a stronger role in guiding the stream restoration.