Protected areas (PAs) are important for conserving endemic and endangered species. Invasive alien species, however, have been identified as a serious threat to global terrestrial PAs. To mitigate, a worldwide assessment of current and potential invasion status and risk in PAs is needed.
Analysing 894 alien animal species, including amphibians, reptiles, birds, mammals and invertebrates, this study used GBIF-mediated occurrences to quantify current establishment across nearly 200,000 PAs worldwide.
Initial assessments found that more than half of the investigated species currently occur in PAs. Only 10 per cent of PAs are home to any alien species, but at least one established alien population is found within 10 km boundaries of ~90 per cent of PAs.
Modelling the climatic niches of the alien species, the authors find that more than 95 per cent of PAs are environmentally suitable for establishment by several of the investigated species.
The predicted richness of alien species in global PAs is nearly 200 times higher than what is observed, suggesting that PAs may be very sensitive to incursions but are currently effective at keeping invaders at bay.