Extrinsic environmental factors, not resident diversity itself, lead to invasion of Ageratum conyzoides L. in diverse communities

Abstract

The relationship between diversity and invasibility might be confounded by extrinsic environmental factors and the evolutionary structure of the resident community. To examine the role of extrinsic environmental factors, species and phylogenetic diversity in regulating community susceptibility to invasion, we established 109 plots either with or without Ageratum conyzoides L. in Liandu, China. We identified all the species in our samples, weighed the aboveground biomass of each species, and measured environmental variables. For all species recorded in our survey, we constructed a community phylogeny using PhytoPhylo mega‐phylogeny as a backbone. We selected the best‐fit environment model based on the minimum corrected Akaike information criteria score to examine the effect of extrinsic environmental variables on the relative abundance of A. conyzoides. Relationship between biodiversity and invasion of A. conyzoides was examined by a multiple regression, in which extrinsic ecological factors and biodiversity were combined to predict the relative abundance of A. conyzoides. To reduce the number of extrinsic variables, the first six components produced by a principal component analysis of environmental variables were used as predictive variables in the multiple regression. The best‐fit environment model indicated that the relative abundance of A. conyzoides was higher in summer and in communities with lower total organic matter and higher total nitrogen in the soil. The multiple regression indicated that only the positive relationship between the Shannon–Wiener diversity of exotics and the relative abundance of A. conyzoides was significant. This result challenges the importance of diversity–resistance to plant invasion. Generalist facilitation might exist between A. conyzoides and other exotic species, although mechanisms for such facilitation are unclear. Overall, our finding suggests the extrinsic factors covarying with diversity are more important than diversity itself in regulating community susceptibility to invasion.

Forest canopy resists plant invasions: a case study ofChromolaena odoratain sub-tropical Sal (Shorea robusta) forests of Nepal

“…Nevertheless, higher species richness of a native community does not necessarily make these communities more competitive and invasion resistant (Levine 2000, Fridley et al 2007). Therefore, besides species richness, other attributes of these communities, for example density, crowding and biomass, may make communities more competitive and resistant to invasion (Kennedy et al 2002, Luo et al 2018, MacLaren et al 2019. In forest stands, native species richness, tree density, canopy cover and shrub/sapling layer are important community attributes of invasion resistance ).…”

Turning Waste into Beneficial Resource: Implication of Ageratum conyzoides L. in Sustainable Agriculture, Environment and Biopharma Sectors

“…However, there were no effects on the biomass, height, wet weight, as well as nutrient contents (vitamin A and C) of tomato [ 19 ]. Extrinsic environmental variables (total soil nitrogen, and organic matter) and the evolutionary structure of the resident community significantly affected the diversity of A. conyzoides [ 20 ].

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Forest canopy resists plant invasions: a case study ofChromolaena odoratain Sal (Shorea robusta) forests of Nepal

“…Nevertheless, higher species richness of a native community does not necessarily make the community more competitive and invasion resistant (Levine 2000, Fridley et al 2007. Besides species richness, other attributes of communities, for example, density, crowding and biomass, potentially make communities more competitive and resistant to invasion (Kennedy et al 2002, Luo et al 2018, MacLaren et al 2019. In forest stands, native species richness, tree density, canopy cover and the shrub/sapling layer are important community attributes for invasion resistance (Gómez et al 2019).…”