Restoration of Forest Riparian Buffer Strips the Upper Reaches of the Qin River, Shanxi Province

摘要

Forest riparian buffer strips have long been recognized for their important functions that include providing shade to reduce water temperature, enhancing deposition of sediments and other contaminants, reducing nutrient loads of streams, stabilizing stream banks with vegetation, reducing erosion caused by uncontrolled runoff, and providing habitats for riparian wildlife. To rehabilitate and reconstruct the riparian buffers at the source of the Qin River in Shanxi Province, China, a field survey and experiments were conducted to provide an example of forest riparian buffer construction in the region. An assessment index system was used to evaluate the Chishiqiao and Zihong rivers, both first-level tributaries of the Qin River. A comprehensive evaluation index system offered indicators of vegetation structural intactness and bank stability including vegetation continuity along the river channel, vegetation coverage and height, abundance of floristic components, associations among vegetation, rock, and soil types, bank structure, and soil erosion modulus. Results indicated that the Chishiqiao River was generally in good condition, and the condition of the Zihong River was average. Ratings for the abundance, arrangement, and coverage of riparian vegetation along the Zihong River were low due to the structural intactness subindex. To improve vegetation coverage, abundance, and collocation forms, we chose typical riparian vegetation zones, including grassland, shrub land, and shrub-grass land, and implemented different treatments, i.e. fencing the vegetation zones, planting grasses or shrubs, and covering with soil and turf. We found that soil hygroscopic coefficient, soil fertility, and total nitrogen content were strongly enhanced. Certain types ofriparian buffer strips that would be suitable in this region are suggested.