Data from: Revisiting Darwin’s naturalization conundrum: explaining invasion success of non-native trees and shrubs in southern Africa

1. Invasive species are detrimental ecologically and economically. Their
negative impacts in Africa are extensive and call for a renewed commitment
to better understand the correlates of invasion success. 2. Here, we
explored several putative drivers of species invasion among woody
non-native trees and shrubs in southern Africa, a region of high floristic
diversity. We tested for differences in functional traits between plant
categories using a combination of phylogenetic independent contrasts and a
simulation-based phylogenetic anova. 3. We found that non-native species
generally have longer flowering duration compared with native species and
are generally hermaphroditic, and their dispersal is mostly abiotically
mediated. We also revealed that non-native trees and shrubs that have
become invasive are less closely related to native trees and shrubs than
their non-invasive non-native counterparts. Non-natives that are more
closely related to the native species pool may be more likely to possess
traits suited to the new environment in which they find themselves and
thus have greater chance of establishment. However, successful invaders
are less closely related to the native pool, indicating evidence for
competitive release or support for the vacant niche theory. 4. Synthesis.
Non-native trees and shrubs in southern Africa are characterized by a
suite of traits, including long flowering times, a hermaphroditic sexual
system and abiotic dispersal, which may represent important adaptations
promoting establishment. We suggest that differences in the evolutionary
distances separating the native species pool from invasive and
non-invasive species might help resolve Darwin's naturalization
conundrum.