Habitat Condition and Vegetation Restoration Patterns in the Water Level Fluctuation Zone of the Three Gorges Reservoir

Abstract

[Objective] The Three Gorges Reservoir’s impoundment has speed up habitat fragmentation and patching in the water level fluctuation zone, and extreme habitat stress has seriously damaged the structure and function of vegetation. Clarifying the habitat status of the water level fluctuation zone of the Three Gorges Reservoir, proposing an adaptive vegetation restoration strategy, and reconstructing the comprehensive ecological function of damaged river corridor are of utmost importance for building regional ecological security pattern and ensuring water resources security of the Yangtze River Basin. [Methods] In response to the prominent issues of vegetation degradation and ecological function damage, we systematically analyzed multiple habitat conditions and their influence on riparian vegetation growth. Focusing on the basic requirements for ecological restoration of damaged river corridor along reservoir banks, a vegetation restoration pattern for construction of suitable microhabitats and optimization of vegetation functional pattern was explored. [Results] The habitat conditions of the water level fluctuation zone were jointly regulated by unique water level rhythm formed by reservoir, operation, climate condition during the exposed, soil erosion and sedimentation and soil environment, which presented a distinctive spatial heterogeneity pattern. Among these, inundation duration, emergence time, and inundation intensity by seasonal water fluctuation were the primary factors affecting plant reproduction and development, while soil erosion, sedimentation burial and soil substrates affected vegetation growth. [Conclusion] Accordingly, water level, site conditions and morphological-functional trait characteristics of various vegetation should be comprehensively considered when planning vegetation restoration in the water level fluctuation zone. Meanwhile, the high-quality stress-resistant species selection, site preparation measures for soil condition improvement, and the zonal optimization of vegetation patterns were beneficial for rebuilding the comprehensive ecological function of the water level fluctuation zone. This provided theoretical support and scientific basis for the ecological management of the water level fluctuation zone in the Three Gorges Reservoir.

Keywords

• habitat stress
• extreme flooding
• soil erosion
• vegetation restoration
• water level fluctuation zone