极端干旱对鄱阳湖碟形湖水生植物群落的影响

The Impact of Extreme Droughts on Aquatic Macrophyte Communities in the Sub-lakes of Poyang Lake

水生植物是水生生态系统的重要组成部分,为底栖动物、鱼类和水鸟提供食物来源和栖息场所。近年来鄱阳湖水位变化剧烈,极端水文事件频发,对水生植物生长产生了不利影响。目前,关于极端干旱对鄱阳湖水生植物的影响报道较少。该研究于2022年7月和2023年7月对鄱阳湖典型碟形湖大湖池、沙湖及常湖池的水生植物群落进行调查,结果表明,2022和2023年鄱阳湖碟形湖平均水深分别为(160.27±50.70)、(58.00±21.46)cm,透明度分别为(49.10±14.41)、(47.25±10.91)cm。浮叶植物菱(Trapa spp.)优势度最大,沉水植物刺苦草(Vallisneria spinulosa)和轮叶黑藻(Hydrilla verticillata)优势度及生物量在2023年有所增加。湖区干旱导致水位降低,水体透明度发生变化,影响了植物群落的物种数,导致植物多样性增加。不同年份碟形湖水位和水体透明度的变化对水生植物多样性有显著影响,2 a间鄱阳湖碟形湖水生植物群落的物种组成差异显著,表现为2023年干旱后挺水和湿生植物比例增加。该研究通过对比分析2 a的监测数据,探讨了极端干旱对碟形湖水生植物的影响,研究结果可为鄱阳湖水生植物的恢复和越冬水鸟的食物资源补充管理提供科学依据。

Aquatic macrophytes play a crucial role in aquatic ecosystems,serving as both food sources and habitats for various organisms,including macrobenthos,fish,and waterbirds.In recent years,Poyang Lake has experienced significant fluctuations in water levels,with frequent extreme hydrological events adversely affecting the growth of aquatic macrophytes.However,limited research has been conducted on the impact of extreme drought on aquatic macrophytes in Poyang Lake.This study investigated the aquatic macrophyte communities in the typical sub-lakes(Dahu Lake,Shahu Lake,and Changhuchi Lake)of Poyang Lake in July 2022 and July 2023.The results indicate that the average water depths of the sub-lake areas in Poyang Lake were(160.27±50.70)and(58.00±21.46)cm in 2022 and 2023,respectively,with corresponding transparency values of(49.10±14.41)and(47.25±10.91)cm.Notably,the dominance of floating-leaved plants,particularly Trapa spp.,was observed in both years,while submerged species such as Vallisneria spinulosa and Hydrilla verticillata exhibited increased dominance and biomass in 2023.The drought in the lake area resulted in a reduction in water level and alterations in water transparency,which affected the species richness of plant communities and promoted plant diversity.Variations in water level and transparency within the sub-lakes across different years exerted significant influence on aquatic macrophyte diversity.Substantial disparities in species composition of aquatic macrophytes communities within the sub-lakes of Poyang Lake between the two years were observed,marked by an augmented proportion of emergent plants and wetland plants after the drought in 2023.This study investigates the impact of extreme drought on aquatic macrophytes in the sub-lakes through a comparative analysis of two years of monitoring data.The findings of this research can provide a scientific basis for the restoration of aquatic macrophytes in Poyang Lake and the management of food resources for overwintering waterbirds.