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 the number of 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, the allocation of management resources, and evaluations of current and future threats. South African regulations first promulgated in 2014 mandated a triennial process of national reports on the status and management of biological invasions. This required a consolidated national list of alien species. This paper outlines the process followed to create this list, describes how the list evolved over time, and highlights lessons learnt, and challenges encountered. Over the production of three status reports, there have been major improvements in how data are presented, how changes are tracked, and the degree to which the information presented is consistent with international best practice. The development of documented and repeatable workflows has ensured that it is now clear why species are included on the list and facilitates reviews and updates. The focus for the next phase is to ensure that all historical data sources are incorporated into the list and to put systems in place to incorporate new information as it becomes available. We conclude with a reflection on what has worked over the last decade, 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 the data sources used and the level of confidence in the data; 4. take a modular approach; 5. document workflows; 6. integrate with reporting requirements; 7. commit dedicated resources; and 8. learn by doing.