Lists of harmful alien organisms: Are the national regulations adapted to the global world?

Legislation on biological invasions has been evolving in recent decades. The use of lists of harmful alien organisms (LHAO) is becoming a widespread policy practice in many countries. LHAO aims to prevent the introduction of undesirable organisms at the pre-border level, regulate their use within the country and deter their spread. However, a systematic review and comparison of the current legislations is lacking. It remains unknown whether there are gaps or weaknesses that may compromise and effective strategy against biological invasions. In this study, a total of 77 LHAO from Australia, Japan, New Zealand, Spain, South Africa, Switzerland, the United Kingdom and the United States of America were evaluated and compared in terms of the taxonomic criteria of inclusion, the impacts of concern and the activities regulated. The number of LHAO has increased exponentially since 1924. Countries widely varied in the number of lists. Within a country, LHAO are scattered across different regulations that consider different impacts and regulate activities from introduction to management. The number of taxa ranged between 0.15 and 55.4 taxa km⁻² in the USA and New Zealand, respectively. These lists totaled 21,029 records of 18,149 different taxa, showing a prevalence of taxa listed as species (rather than genera of higher ranks). Primary attention is paid to the kingdoms Animalia and Plantae. Taxa affecting livelihood/uses were more prevalent than those related to biodiversity and human health impacts. The most common regulations concern trade and tenure followed by use. This study reveals the need for more comprehensive (intersectoral) regulations on invasive alien species within countries as well as the development of homogeneous regulations adapted to the globalized world.