Determinants of global variation in taxonomic and phylogenetic diversity of invasive plants

Abstract

Information on the determinants of taxonomic and phylogenetic diversity of invasive plant species is crucial for managing invasive plants. With globalization, most countries have experienced substantial economic losses and environmental damage due to biological invasions. We analysed the determinants of variation in the diversity and phylogenetic structure of invasive plants among countries worldwide.

To do so, we used a comprehensive checklist of invasive plants in 152 countries worldwide to calculate taxonomic and phylogenetic diversity (i.e. Faith’s PD metric) and phylogenetic structure, using mean phylogenetic distance (MPD) and mean nearest taxon distance (MNTD). We then combined these data in minimum adequate models with data on geographic, climatic, socio-economic and international trade variables. We also conducted randomization tests to determine whether the phylogenetic diversity of invasive plants in these countries was clustered or overdispersed.

Taxonomic and phylogenetic diversity of invasive plants exhibited spatial congruence. Taxonomic and phylogenetic diversity were positively correlated with insularity, mean annual precipitation (MAP) and HS-12 (seeds, grains and medicinal plants) import values per capita, but negatively associated with mean annual temperature (MAT) and HS-07 (vegetables) import evenness. In addition, taxonomic diversity also increased with airport density, HS-12 import evenness and lower HS-08 (fruit and nuts) imports. MPD increased with greater land area and airport density and fewer HS-12 exporting source countries. MNTD increased with MAT but declined with greater land area and insularity. Phylogenetic clustering occurred in 28.9%–49.3% of countries, whereas phylogenetic overdispersion was rare, observed only in 0.6%–5.3% of countries.

Synthesis. Our study reveals that variation in taxonomic and phylogenetic diversity of invasive plant species among countries is shaped by geographic, socio-economic, climatic and international trade factors. Nearly one-third of the countries showed phylogenetic clustering of invasive plant species, indicating a relatively consistent global pattern. These findings underscore the importance of integrating both taxonomic and phylogenetic perspectives in invasion ecology, emphasizing the need for regionally tailored management strategies that effectively account for regional geographic, climatic, socio-economic and trade-related factors to mitigate future plant invasions.