Effects of nutrient levels on growth characteristics and competitive ability of water hyacinth (Eichhornia crassipes), an aquatic invasive plant
不同营养水平对外来物种凤眼莲生长特征及其竞争力的影响

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 bod-ies also account for its rapid spread. Based on a series of pot experiments, we examined the growth char-acteristics of water hyacinth at three different nutrient levels, as well as its competitive effects on two na-tive 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 hya-cinth, 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 ecosys-tem function.