DOI: 10.3391/ai.2025.20.3.160924

Authors: Xiaolong Huang, Heyun Wang, Songyang Li, Leyang Xu, Zhaoshi Wu, Hu He, Kuanyi Li

Abstract: As global warming continues, increasing minimum winter temperatures may no longer limit the northward expansion of invasive species, particularly those from tropical zones. A mesocosm experiment with a chronosequence approach (space-for-time trade-off) was used to examine the effects of water level variation on the traits of the invasive aquatic plant water hyacinth [Pontederia crassipes (formerly Eichhornia crassipes)] collected from freezing, chilling and warm overwintering locations in China. We hypothesized that the phenotypic plasticity of the plant, particularly its ability to adjust its root morphology and topology in response to vernal water level rise, enhances its capacity to invade freshwater ecosystems. The results revealed significant plasticity in the response of the plants to water level, with plant traits such as total biomass, diaspore number, leaf area, specific leaf area, root length, and photosynthetic efficiency significantly increasing under a 10-cm water level, which can be regarded as a moderate overwintering water level. However, the plants from the warm location did not perform better than did those from the freezing or chilling locations, possibly because the harsh winter conditions reduced plant biomass but did not negatively affect the plants at the gene level. These findings highlight phenotypic plasticity in rooting behavior, which enables plant survival and growth during overwintering in the littoral zone, allowing P. crassipes to withstand low temperatures and to rapidly proliferate during the vernal water rise period. This study highlights the importance of early detection and management strategies to control the spread of P. crassipes, particularly given the trends in global climate change, which may facilitate its northward expansion. The use of P. crassipes as a model plant is recommended for studying the responses of invasive aquatic plants to global change in freshwater ecosystems.

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DOI: 10.3391/ai.2024.19.1.117155

Authors: Uhram Song, Seok Hyeon Oh, Byoung Woo Kim, Seonah Jeong, Hojun Rim

Abstract: Freshwater ecosystems are vulnerable to the invasion of exotic aquatic plant species because of the great likelihood of the introduction of exotic species, and the lack of barriers that block introduced species. Water hyacinth, Pontederia crassipes Mart., is one of the world’s most invasive alien plant species damaging freshwater ecosystems worldwide. Here, we monitored the water hyacinth population on Jeju island, Korea, to assess current invasion risks. Furthermore, we investigated how water hyacinth affects water pH because pH is an important determinant of the distribution of other aquatic plants, and thus a good indicator of aquatic ecosystem health. Water containing water hyacinth had a pH of 5.3, while that with water hyacinth and soil had a pH of 4.8 72 hours after the start of the experiment. Water hyacinth extracts contained shikimic acid, stearic acid, and palmitic acid, which are possible compounds that caused a decline in water pH. Water hyacinth also inhibited the growth of the aquatic plant species, Spirodela polyrhiza and Lemna perpusilla. These results imply that invasion of water hyacinth adversely impacts the abiotic and biotic characteristics of aquatic ecosystems. Moreover, monitoring the water hyacinth population suggests that this invasive aquatic plant overwinters on Jeju island. Therefore, regular monitoring and subsequent control of water hyacinth population can prevent its expansion in the aquatic habitats of Jeju island and the southern region of the Korean peninsula.

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