Lessons and challenges in creating alien species lists: insights from South Africa’s national reports on the status and management of biological invasions

Information on alien species present in a country, their status (establishment, distribution, impacts), and how they entered and move around the country is crucial for effective management. Such information underpins regulations, allocation of management resources, and evaluations of current and future threats. South African regulations, first promulgated in 2014, mandate a triennial process of national reports on the status and management of biological invasions, requiring a consolidated list of alien species. Here we describe the process followed to create such a list, how the list evolved over time, and highlight lessons learnt and challenges encountered. Over the production of three status reports, there have been major improvements in how data were presented, how changes were tracked, and the degree to which the information was consistent with international best practice. The development of documented and repeatable workflows ensured clarity on why a species was included on the list and facilitated reviews and updates. The focus for future reports is to include all historical data sources and to put processes in place to incorporate new information as it becomes available. We conclude with a reflection on what has worked and identify eight recommendations for those developing national lists of alien species: 1. structure data and make them available; 2. use data standards and metadata; 3. list data sources and levels of confidence; 4. take a modular approach; 5. document workflows; 6. integrate with reporting requirements; 7. commit dedicated resources; and 8. learn by doing.