Submerged plants are crucial for maintaining a clear water state in lakes, and their distribution area is usually determined by the lowest distribution boundary (LDB). However, LDBs of submerged macrophytes often exhibit species differences and vary with seasonal water level fluctuations. In this study, we carried out a three-year field investigation to compare differences in the LDBs of three submerged macrophyte species (i.e., Vallisneria natans, Ceratophyllum demersum, and Potamogeton maackianus) and explore their distinct determinants. We assumed that LDB differences would exist among the three species and that water level (WL) would be a key environmental driver of LDB dynamics, with an association between the LDBs of submerged macrophytes and water level fluctuations. Indeed, our results showed significant seasonal differences between C. demersum and V. natans in the period of September - May, with mean annual values in the order (low to high) V. natans, C. demersum, and P. maackianus. Furthermore, water level was a major driving force of the LDB dynamics of the three species. Changes in the LDBs of the three species in response to water level fluctuations could be divided into three periods: i.e., recovery growth period (April to June), stress tolerance period (July to September), and recession period (October to following March). This study not only clarifies the impact of water level on submerged macrophyte growth and distribution, but also has larger practical implications for the ecological restoration and management of large deep lakes.

沉水植物对于维持湖泊清澈的水体状态至关重要，它们的分布区域通常由最低分布边界 (LDB) 决定。然而，沉水植物的LDBs往往表现出物种差异，并随着季节性水位波动而变化。在这项研究中，我们进行了一个为期三年的实地调查，比较三种沉水植物品种（即的LDB差异苦草，金鱼藻，和微齿眼子菜) 并探索它们不同的决定因素。我们假设这三个物种之间存在 LDB 差异，并且水位 (WL) 将是 LDB 动态的关键环境驱动因素，与沉水大型植物的 LDB 与水位波动之间存在关联。事实上，我们的结果表明，在 9 月至 5 月期间，C. demersum和V. natans之间存在显着的季节性差异，年均值的顺序为（从低到高）V. natans、C. demersum和P. maackianus。此外，水位是三个物种 LDB 动力学的主要驱动力。三个物种LDBs响应水位波动的变化可分为三个时期：恢复生长期（4-6月）、抗逆期（7-9月）和衰退期（10-次年3月） . 本研究不仅阐明了水位对沉水植物生长和分布的影响，而且对大型深湖生态修复和管理具有较大的实际意义。