An Exploration of the Genetic Dynamics of Submerged Ceratophyllum demersum in a Freshwater Lake Under Conservation

Although the effects of human disturbance on population genetic variation in plants have been widely studied, little attention has been paid to the impact of environmental changes on genetic dynamics after the implementation of conservation measures. Previously, freshwater Caohai Lake, famous for its abundant aquatic plants and birds, was strongly disturbed by tourism and other human activities; however, strict protective measures have been implemented since 2019. Therefore, the lake provides a suitable natural sampling ecosystem for investigating genetic variation changes following the implementation of conservation measures. Samples of cosmopolitan aquatic Ceratophyllum demersum were collected in 2019 and 2021, and they were analyzed using microsatellite primers. Our results show the presence of considerable genetic diversity in the C. demersum Caohai population. Although human disturbance decreased, the impact of natural disturbances, such as water flow and bird activities, persisted and may have increased. For C. demersum, water flow may cause vegetative propagules of different genotypes to pool in the downstream area of the lake. At sites with a very rich diversity of birds, increasing bird activities may augment the advantage of competitive clones in communities. Therefore, the continuous monitoring of the population’s genetic variation and the impact of related environmental factors is required for the efficient management of the lake ecosystem.