The worldwide networks of spread of recorded alien species

The study focuses on understanding the patterns of how alien species, those not native to a particular region, spread across the world. Such insights are essential for predicting and preventing biological invasions, which can have significant ecological, economic, and health impacts. The research aimed to identify universal patterns in the spread of alien species that are common across different taxonomic groups but specific to regions.

Using a comprehensive dataset that included records of the first appearances of alien species in different countries, the study analyzed the spread of four major biological groups: birds, nonmarine fishes, insects, and vascular plants. The analysis applied a network approach to uncover recurrent patterns of first species records across countries worldwide.

The research revealed intriguing patterns in the spread of alien species. It identified a few countries as consistent early recorders of these species, which often played a central role in their subsequent spread to other countries. These early-recording countries served as dispersal hubs, influencing global invasion routes. Notably, geographical proximity, climatic similarity, and international trade were significant factors in determining the spread patterns.

In essence, the study found that the spread of alien species occurs hierarchically. A small number of countries act as major hubs for species dispersal, with their influence extending globally. These countries were typically connected by strong trade relationships, shared species records, and similar climates. In contrast, some countries tended to record new alien species later than others, indicating variations in the timing of species introduction.

Understanding these patterns of alien species spread is crucial for targeted prevention and management strategies. By focusing on countries that have emerged as hubs for early species spread, it is possible to have a substantial impact on reducing global biological invasions. These key countries can also serve as early-warning systems, helping to boost national efforts to prevent and prepare for invasions.

In summary, this study provides valuable insights into the complex dynamics of alien species spread, offering a framework for enhancing efforts to predict, prevent, and manage biological invasions on a global scale. It highlights the critical role of specific countries as hubs in shaping the spread of alien species across the world.

For the full article: https://www.pnas.org/doi/10.1073/pnas.2201911120