Plant extinctions and introductions lead to phylogenetic and taxonomic homogenization of the European flora.
Abstract
Human activities have altered the composition of biotas through two fundamental processes: native extinctions and alien introductions. Both processes affect the taxonomic (i.e., species identity) and phylogenetic (i.e., species evolutionary history) structure of species assemblages.
Considering both native losses and alien additions in concert reveals that plant invasions in Europe since AD 1500 exceeded extinctions, resulting in (i) increased taxonomic diversity (i.e., species richness) but decreased phylogenetic diversity within European regions, and (ii) increased taxonomic and phylogenetic similarity among European regions. As a result, floras of many European regions have partly lost and will continue to lose their uniqueness.
The results suggest that biodiversity needs to be assessed in terms of both species taxonomic and phylogenetic identity, but the latter is rarely used as a metric of the biodiversity dynamics.