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Most biological invasion literature—including syntheses and meta-analyses and the resulting theory—is reported from temperate regions, drawing only minimally from the tropics except for some island systems. The lack of attention to invasions in the tropics results from and reinforces the assumption that tropical ecosystems, and especially the continental tropics, are more resistant to invasions. We have critically assessed biological invasions in the tropics and compared them with temperate regions, finding relatively weak evidence that tropical and temperate regions differ in their invasibility and in the traits that determine invader success and impacts. Propagule pressure and the traits that promote adaptation to disturbances (e.g., high fecundity or fast growth rates) are generally favorable to invasions in both tropical and temperate regions. We emphasize the urgent need for greater investment and regional cooperation in the study, prevention, and management of biological invasions in the tropics. 

Abstract Species radiations, despite immense phenotypic variation, can be difficult to resolve phylogenetically when genetic change poorly matches the rapidity of diversification. Genomic potential furnished by palaeopolyploidy, and relative roles for adaptation, random drift and hybridisation in the apportionment of genetic variation, remain poorly understood factors. Here, we study these aspects in a model radiation,Syzygium, the most species-rich tree genus worldwide. Genomes of 182 distinct species and 58 unidentified taxa are compared against a chromosome-level reference genome of the sea apple,Syzygium grande. We show that whileSyzygiumshares an ancient genome doubling event with other Myrtales, little evidence exists for recent polyploidy events. Phylogenomics confirms thatSyzygiumoriginated in Australia-New Guinea and diversified in multiple migrations, eastward to the Pacific and westward to India and Africa, in bursts of speciation visible as poorly resolved branches on phylogenies. Furthermore, some sublineages demonstrate genomic clines that recapitulate cladogenetic events, suggesting that stepwise geographic speciation, a neutral process, has been important inSyzygiumdiversification.