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

: 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. Resumen: Para que la ecologia de invasiones sea una aproximacion cuantitativa a la conservacion se deben identificar predictores de exito solidos. Aunue a menudo se menciona casualmente, la taxonomia nunca ha sido evaluada a fondo como un agente de prediccion. Utilice probabilidades binomiales para identificar patrones taxonomicos en el exito de avifauna global. Cuando mucho, el 2.54% del total de especies de aves son consideradas como exoticas establecidas exitosamente en alguna otra parte del mundo. La distribucion de estas especies en los taxa superiores dista de ser aleatoria. Siete familias presentaron mas especies exoticas establecidas que las esperadas al azar: Anatidae (patos y gansos), Phasianidae (faisanes), Passeridae (gorriones y pinzones estrildidos), Psittacidae (loros y afines), Columbidae (palomas), Rheidae (reas) y Odontophoridae (codornices del Nuevo Mundo). Este patron taxonomico parece ser guiado por la influencia humana en la probabilidad de transporte. Las familias Anatidae, Odontophoridae y Phasianidae tienen mayor numero de especies que arribaron a su rango invasivo para ser explotadas (i.e., caceria) que el esperado. Las familias Passeridae y Sturnidae (estorninos y minahs) tienen un mayor numero de especies usadas como mascotas que el esperado al azar. Asi los rasgos que incrementan la probabilidad de transporte con finalidad utilitaria presentan un patron taxonomico. Esta influencia humana en la probabilidad de transporte incrementa la cantidad de especies introducidas pero no incrementa la proporcion de especies que se establecen exitosamente. Al asignar riesgo de invasion parece fundamental entender la interaccion entre atributos de las especies que influyen en su establecimiento y transporte.