金沙江下游典型库区消落带植被恢复模式

消落带植被分布、生活型、多样性的调查研究显著促进了消落带植被恢复技术的进步，然而相邻两梯级库区消落带植被分布的差异以及植被群落特征的年际变化并不明确。此外，金沙江下游部分区域表现出一定的干热特征，其影响下的消落带植被群落特征有待深入了解。基于2019年和2021年向家坝和溪洛渡库区消落带植被调查结果，分析表明：(1)金沙江下游消落带按照下垫面特性主要分为硬岩型、软岩型、松软堆积型3种类型，坡度平缓的松软堆积型消落带是植被恢复的主要类型；(2)整体上，消落带优势植被类型是一年生和多年生草本，单优势种、少优势种群落较为普遍，两个库区消落带优势种重要值差异显著，植被生活型较少；(3)向家坝、溪洛渡库区消落带在分别经历6次和8次周期性水淹后，消落带植被分布与群落物种多样性特征变化不显著，表明消落带植被群落结构相对稳定。综上说明向家坝、溪洛渡两个相邻的梯级库区消落带植被恢复需要以灌草为主，且具有不同的潜在恢复模式，因此需要对应采取不同的恢复策略。研究对于科学指导金沙江下游梯级水电站库区消落带植被恢复具有重要意义。

Vegetation restoration pattern of water-level-fluctuation zone in two cascaded reservoirs in the lower Jinsha River

The investigation and research on the distribution, life-forms, and diversity of the vegetation have greatly promoted the progress of the restoration technology of the vegetation in water-level-fluctuation zone of the reservoir area. However, previous studies did not answer the question of how the distribution of vegetation in the riparian zone differed between two cascade reservoirs and the associated interannual variation of vegetation community characteristics. In addition, some areas in the lower Jinsha River belong to hot-dry valleys. The vegetation of the water-level-fluctuation zone in the reservoir areas of the lower Jinsha River is partly affected by the high temperature and arid climate, which would have a certain influence on the vegetation community characteristics of the water-level-fluctuation zone. That is, in the area of the lower Jinsha River, it is still unclear how the distribution of vegetation in the water-level-fluctuation zone in two cascaded reservoir areas and their interannual change. In 2019 and 2021, the vegetation communities of the neighboring Xiangjiaba and Xiluodu reservoir areas were investigated, respectively. The results showed that:(1) there were mainly three types of water-level-fluctuation zone in the lower Jinsha River:type of hard rock, type of soft rock, and type of loose and soft sedimentary zones with soil or sediments accumulated. Plants were mainly distributed in the loose and soft sedimentary zones with gentle slopes; (2) Overall, the dominant vegetation in the sedimentary zones were annual and perennial herbaceous plants. The single dominant species and less dominant species communities were common. Due to the periodic inundation and dry heat, the vegetation in the zone had a zonal distribution along the water level elevation. Significant differences in the important values of dominant species in the two reservoirs. Generally, a relatively few vegetation life types were found in the studied areas; (3) The vegetation community index of the zone in Xiangjiaba and Xiluodu reservoirs did not change significantly after six and eight periodic inundations, indicating that the vegetation community structure of the zone was relatively stable in the two-year time scale. Combining the differences in the important values of dominant species in the two reservoir areas, different vegetation restoration patterns of the water-level-fluctuation zone of Xiangjiaba and Xiluodu reservoirs were clarified. In summary, it is suggested that the restoration of vegetation in the fallout zone of Xiangjiaba and Xiluodu, two adjacent terrace reservoirs, needs to be dominated by irrigation and grass, and has different potential restoration patterns, so different restoration strategies need to be adapted accordingly. The study is of great significance for scientific guidance on the restoration of vegetation in the fallout zone of the reservoir area of the lower Jinsha River.