Abstract: We investigated population dynamics, viability, and environmental adaptation of the rare and endangered aquatic plant Ottelia acuminata var. jingxiensis, distributed in the Chengjiang River in Hechi and the Equan River in Jingsi, Baise. Point pattern analysis was used to examine the spatial pattern and spatial correlation of the population at different levels. The results showed that the proportion of class III clusters was higher than that of class I and class II clusters in both sampling sites. The karst landscape’s water environment has resulted in a unique distribution pattern for the population. At small scales, both sampling sites exhibited an aggregated distribution, which transitions from aggregation to random or uniform distribution as the scale increases. Class I, Class II, and Class III clusters in both sampling plots exhibited a positive correlation at small scales, which shifted to negative at larger scales. The number of young plants in the populations was insufficient, with population renewal currently in a negative growth phase. At small scales, the population exhibited an aggregated distribution. The interdependence among different classes was an adaptation strategy of Ottelia acuminata var. jingxiensis populations.

Key words: Ottelia acuminata var. jingxiensis, point pattern analysis, spatial distribution pattern, intraspecific correlation