Using Taxonomy to Predict Success among Introduced Avifauna: Relative Importance of Transport and Establishment

Abstract: For invasion ecology to become a quantitative approach to conservation, robust predictors of success must be identified. Taxonomy, although often casually mentioned, has never been thoroughly assessed as an agent of prediction. I used binomial probabilities to identify taxonomic patterns in establishment success among global avifauna. At most, 2.54% of all avian species are considered successfully established exotics somewhere in the world. The distribution of these species among higher taxa is far from random. Seven families contained more successfully established exotic species than expected by chance: Anatidae (ducks and geese), Phasianidae (pheasants), Passeridae (sparrows and estrildid finches), Psittacidae (parrots and allies), Columbidae (pigeons and doves), Rheidae (rheas), and Odontophoridae (New World quails). Human influence on probability of transport appears to drive this taxonomic pattern. Anatidae, Odontophoridae, and Phasianidae hold far more species than expected that arrived in their invasive range for exploitation (i.e., hunting or game). Passeridae and Sturnidae (starlings and mynahs) have more pet species than expected by chance. Thus, traits that enhance probability of purposeful transport exhibit a taxonomic pattern. This human influence on probability of transport increases the quantity of species introduced but does not increase the proportion of species that successfully become established. When invasion risk is assigned, it is vital to understand the interaction between species-specific attributes that influence establishment and transportation.