Salt tolerance assessment of aquatic and wetland plants: increased salinity can reshape aquatic vegetation communities

• Published in: Hydrobiologia 2023-11, Vol.850 (20), p.4575-4587
• Main Authors: Tootoonchi, Mohsen, Gettys, Lyn A., Ferrell, Jason A., Erickson, John E., Bhadha, Jehangir H.
• Format: Article
• Language: English
• Subjects: Alternanthera philoxeroides; Aquatic ecosystems; Aquatic plants; Aquatic reptiles; Biomedical and Life Sciences; Ecology; Ecosystems; Effects of Changes in Salinity; Encroachment; Floating plants; Flora; Fresh water; Freshwater; Freshwater & Marine Ecology; Freshwater ecosystems; Indigenous plants; Indigenous species; Inland water environment; Introduced species; Invasive species; Life Sciences; Mortality causes; Native organisms; Native species; Nonnative species; Panicum repens; Plant communities; Plant growth; Plants; Plants (botany); Regression models; Salinity; Salinity effects; Salinity gradients; Salinity tolerance; Salinization; Salt tolerance; Schinus terebinthifolius; Soils, Salts in; Survival; Toxicity tests; Vegetation; Wetlands; Zoology
• ISSN: 0018-8158; 1573-5117
• DOI: 10.1007/s10750-022-04934-5

Salinization is a great threat to wetlands and freshwater ecosystems. Increased salinity can disturb native aquatic vegetation and provide an empty niche for invasion of non-native species. To understand the fate of aquatic flora under increased salinity levels, 14 dominant wetland species with different growth forms (submersed, amphibious, floating-leaved, emergent and woody/tree) were exposed to increased salinity conditions. The objective was to assess the salt tolerance threshold for each species and model their performance in response to a salinity gradient ranging from 0.2 to 20 parts per thousand (ppt). Plant growth and survival rate were analyzed using a nonlinear regression model to project sublethal salinity concentrations that would reduce biomass and visual quality of each species by 50% (LC 50 ). Results showed that a few non-native species (alligatorweed: Alternanthera philoxeroides (Mart.) Griseb., torpedograss: Panicum repens L., and Brazilian peppertree: Schinus terebinthifolius Raddi) survived 20 ppt salinity, whereas all other native and non-native species perished at salinity below 10 ppt. Increased salinity can suppress salt-sensitive native plants and increase the opportunity of invasion for salt-tolerant non-native species. This suggests that alligatorweed, torpedograss and Brazilian peppertree pose a more significant threat to the ecosystem if salinity levels continue to increase in freshwater ecosystems and exacerbate the encroachment of non-native species into native plant communities.