Geographic biases in invasiveness: the case of Asian and African parakeets

When evaluating the invasive risk of a species, researchers commonly use environmental-based predictions. This study, however, suggests that including international trade data and variability in geographical origin may lead to much more thorough risk analyses. The authors compiled occurrences of ring-necked parakeets from GBIF and other sources and built distribution models for the birds' native niches in Africa and Asia, respectively. When comparing with invasive ranges in Europe, their results show that the distribution here is mainly explained by geographical origin of the birds and time since introduction. Their models indicate that while most of Europe is suitable for the Asian population, almost no habitat is suitable for the African population. This finding is supported by recent evidence that genetic markers of established invaders mostly match those of Asian populations, although introduced in similar numbers as African birds.