Effects of nutrient levels on growth characteristics and competitive ability of water hyacinth (Eichhornia crassipes), an aquatic invasive plant

Abstract

Water hyacinth (Eichhornia crassipes), a noxious invasive species, has infested vast aquatic ecosystems. Besides its extraordinary adaptive ability and clonal growth, the eutrophication of water bodies also account for its rapid spread. Based on a series of pot experiments, we examined the growth characteristics of water hyacinth at three different nutrient levels, as well as its competitive effects on two native plants Ludwigia peploides ssp. stipulacea and Hydrilla verticillata. Our results showed that the mean number of ramets, mean height and total biomass of water hyacinth significantly increased with increase of nutrient level, indicating that nutrient-enriched water accelerated the growth and propagation of water hyacinth, which, as a result, reduced the growth of L. peploides ssp. stipulacea and H. verticillata. This suggests that eutrophication further boosts the competitive advantages of water hyacinth over native plants, and thus facilitates the invasion of this weed in water bodies. Thus, alleviating water pollution is a key method for controlling the spread of water hyacinth in order to protect native biodiversity and ecosystem function.