Seminar: Angela Moles

Rapid evolution in introduced species: will introduced plant species eventually be accepted as unique native taxa?

Prof. Angela Moles (University of New South Wales, Australia) 

Introducing species to a new environment creates excellent conditions for evolution, as the species are released from their old enemies and subjected to a new suite of biotic and abiotic pressures. Our work with herbarium specimens has shown that 70% of the annual plant species introduced to Australia have undergone significant morphological change since their introduction. We used genetics to locate the exact source population for one species that had shown morphological change through time, Arctotheca populifolia, which was introduced to Australia from South Africa in the 1930s. We grew Australian and South African populations of Arctotheca populifolia in a common garden experiment. We found substantial morphological, physiological and chemical differences between the native and introduced populations. If we can’t eradicate introduced species (and we seldom can), then it seems inevitable that they will eventually evolve to become unique new taxa (whether we like it or not). At this point, we will have to decide whether to accept them as new native species, or try to exterminate them. While most Australian ecologists don’t like the idea yet, I think acceptance of introduced species is just a matter of time. I will be interested to hear what you think!