Alien flora in Zimbabwe: An updated checklist

The naturalised flora diversity and richness in Zimbabwe has continued to increase over the past decades. Alien species inventories provide baseline data needed to understand naturalisation dynamics, historical invasion patterns and impacts. Therefore, an updated inventory of the alien flora of Zimbabwe, providing details about the taxa, life forms, their occurrence at regional level, geographical origins, types of habitats colonised and degree of naturalisation is presented. The checklist comprises 476 alien plant taxa, that is, 108 (23%) casuals, 278 (58%) naturalised and 90 (19%) invasive. The most represented families are Asteraceae (65 taxa), Poaceae (63), Fabaceae (58), Solanaceae (30) and Amaranthaceae (23). More than half (51.3%) of the alien plant taxa are primarily herbs, followed by trees (16%), grasses (13%), shrubs (11%) and climbers (8%). The central (77%) and eastern (67%) floristic regions of Zimbabwe have the largest proportion of alien flora in the country. The majority of these alien taxa are native to the Americas (49%), followed by Asia (30%) and Europe (19%); with 55% of the taxa introduced intentionally as ornamentals, while 22% were introduced accidentally. Most of the alien plant taxa have been recorded as ruderals (48%) and agricultural weeds (46%). Results of this study provide baseline data required to monitor and manage alien plant invasions in the country.