Effects of salt stress on interspecific competition between an invasive alien plant Oenothera biennis and three native species

Abstract

Biological invasions and soil salinization have become increasingly severe environmental problems under global change due to sea-level rise and poor soil management. Invasive species can often outcompete native species, but few studies focus on whether invasive alien species are always superior competitors under increasing stressors. We grew an invasive grass species, Oenothera biennis L., and three native grass species (Artemisia argyi Lévl. et Vant., Chenopodium album L., and Inula japonica Thunb.) as a monoculture (two seedlings of each species) or mixture (one seedling of O. biennis and one native species seedling) under three levels of salt treatments (0, 1, and 2 g/kg NaCl) in a greenhouse. We found that invasive O. biennis exhibited greater performance over native C. album and I. japonica, but lower performance compared to A. argyi, regardless of the soil salinity. However, salinity did not significantly affect the relative dominance of O. biennis. Interspecific competition enhanced the growth of O. biennis and inhibited the growth of I. japonica. Although O. biennis seedlings always had growth dominance over C. album seedlings, C. album was not affected by O. biennis at any salt level. At high salt levels, O. biennis inhibited the growth of A. argyi, while A. argyi did not affect the growth of O. biennis. Salt alleviated the competitive effect of O. biennis on I. japonica but did not mitigate the competition between O. biennis and the other two native species. Therefore, our study provides evidence for a better understanding of the invasive mechanisms of alien species under various salinity conditions.

Chlorophyll fluorescence characteristics and H2O2 contents of Chinese tallow tree are dependent on population origin, nutrients and salinity

“…Previous studies have reported the detrimental effects of nutrient deficiency and salinity on invasive plants, particularly in terms of their growth and photosynthetic phenotype characteristics ( Funk and Vitousek 2007 ; Funk 2013 ; Pintó-Marijuan and Munné-Bosch 2013 ; Yang et al 2015a , b , 2022 ; Guo et al 2023 ). They also indicated that an appropriate amount of salt has a promoting effect on the growth and development of plants, enhancing their stress resistance ( Li et al 2015 ; Liu et al 2023 ).…”