Nutrient enrichment alters impacts of Hydrocotyle vulgaris invasion on native plant communities

Abstract

Nutrients may affect the invasiveness of alien plants and the invasibility of native plant communities. We performed a greenhouse experiment to investigate the interactive effect of invasion by a clonal herb Hydrocotyle vulgaris and nutrient enrichment on biomass and evenness of native plant communities. We established three types of plant communities (H. vulgaris alone, native plant communities without or with H. vulgaris) under low and high levels of nutrients. Native communities consisted of eight native, terrestrial species of three functional groups, i.e. four grasses, two legumes, and two forbs. Invasion of H. vulgaris had no effect on biomass of the native community, the functional groups, or the individual species. High nutrients increased biomass of grasses, but reduced evenness of the community. High nutrients also decreased the competitive effect, and the relative dominance index of H. vulgaris. Therefore, high nutrients reduced the competitive ability of H. vulgaris and enhanced the resistance of the native community to invasion. The results provide a basis for management strategies to control the invasion and spread of H. vulgaris by manipulating resource availability to support native communities.

Spatial environmental heterogeneity may drive functional trait variation in Hydrocotyle vulgaris (Araliaceae), an invasive aquatic plant

“…H. vul-garis is an aquatic herb native to Europe and North Africa that has invaded a wide range of habitats in Zhejiang Province, China (Miao et al 2011, H. Wang et al 2016. H. vulgaris is capable of expanding naturally in moist non-native areas, and its clonality contributes to its success as an invader (Miao et al 2011, Liu et al 2016. In addition, H. vulgaris can quickly establish itself in non-native areas (Miao et al 2011, Liu et al 2016.…”

“…H. vulgaris is capable of expanding naturally in moist non-native areas, and its clonality contributes to its success as an invader (Miao et al 2011, Liu et al 2016. In addition, H. vulgaris can quickly establish itself in non-native areas (Miao et al 2011, Liu et al 2016. For example, H. vulgaris was introduced into Xixi Wetland in Zhejiang as an ornamental plant in the 1990s (Miao et al 2011).…”

“…Here, we propose the hypothesis that environmental spatial heterogeneity might drive functional trait variation of the IAP H. vulgaris across a large scale. To test this hypothesis, 6 functional traits, including petiole length, interval length (a clonal trait), leaf area, specific interval length (a clonal trait), specific leaf area, and chlorophyll content, were used to test the trait−environment relationship for H. vulgaris across 99 study plots located at 7 field sites in Zhejiang Province and Shanghai City (the administrative region of Shanghai City was integrated into Zhejiang Province for this study; Axmacher & Sang 2013, Liu et al 2016, Stark et al 2017, Wu et al 2017. We explored the environmental drivers of functional trait variation in H. vulgaris to predict the functional traits across a large scale.…”

“…PL and IL were measured in the field, and collected stems and leaves were stored in a cooler with ice packs and a damp paper towel. All plant parts were separately oven-dried at 70°C for at least 48 h and then weighed (Liu et al 2016). LAs were scanned using an Epson Dual Lene system prior to drying.…”

Nitrogen immobilization may reduce invasibility of nutrient enriched plant community invaded by Phragmites australis

“…Thus, the rehabilitation of those wetlands is the priority of the natural resource management agencies (government and private) in Australia 43,44 . This hypothesis is associated with the resource-ratio hypothesis, that explains plant community composition influenced by relative abundance of limiting resources in soil 45,46 . Thus, the resource (nutrient) manipulation limits the availability to the target dominating plant species, but it may benefit the desired native species 47 .…”