湖泊水动力对水生植物分布的影响

水动力作为湖泊水生植物恢复的关键限制性因子,其对水生植物的影响机制是当前迫切需要关注的科学问题。从水动力作用下水生植物的分布、水生植物受力以及水生植物自身机械抗性3个方面系统梳理了当前的研究方法与结论。结果表明,水生植物在河流湖泊中的丰度、空间分布与水动力密切相关,各物种对水流胁迫表现出不同的响应;植物在水动力作用下的受力观测和研究主要依赖模拟试验,通过计算定量表征不同物理外型物种在水动力作用下的受力,明确了生物量和植物系数等影响受力的关键参数,为不同塑形物种受力的对比分析提供了研究方法;植物机械抗性主要基于测力装置观测,通过断裂应力、弯曲力等生物力学参数表征。在当前研究背景下,水生植物尤其是沉水植物在湖泊中的实际受力情况依然是研究难点,需要借助新的观测手段和研究方法来阐明植物在复杂的湖泊水动力环境下的实际受力特征。此外,还需要进一步开展水生植物在湖泊中的实际受力与植物自身机械抗性的耦合研究,这是开展水生植物响应湖泊水动力机理研究的关键。

A review of the studies on the response of aquatic vegetation to hydrodynamic stress in lakes

Hydrodynamics is considered to play a crucial role in the propagation of aquatic plants; however, the mechanism underlying hydrodynamic effects on aquatic plants is poorly understood. This article reviews the current research methods and conclusions from the following three perspectives:1) distribution of aquatic plants under the influence of hydrodynamic forces; 2) hydraulic forces; and 3) biomechanical properties of aquatic plants. The results showed that the abundance and spatial distribution of aquatic plants in rivers and lakes are closely related to hydrodynamics. Furthermore, different species of plants respond to water flow stress differently. The findings on the hydraulic force of aquatic plants mainly relied on laboratory tests, and related physical parameters could be calculated quantitatively. Biomass and plant coefficients were demonstrated to be the critical parameters affected by hydraulic forces. These provide research approaches for comparative analyses of hydraulic forces on different plant species. Biomechanical properties of aquatic plants were characterized using break and bending forces measured by force-measuring devices. It is possible that the determined hydraulic forces of aquatic plants based on laboratory tests are different from the actual values, especially for submerged macrophytes. Therefore, more accurate investigation methods and statistical analyses are needed to quantify the actual plant hydraulic stress in complex hydrodynamic conditions in lakes. In addition, further studies could also focus on the threshold value of hydraulic and biomechanical forces, which is key to studying the mechanism of the response of aquatic plants to hydrodynamic stress.