Invasive species hit the Global South significantly harder than previously assumed

Invasive species hit the Global South significantly harder than previously assumed Swati Mestri Scientific Editor Robert Egan Senior Editor Invasive alien species are among the world's leading drivers of species extinction. However, previous global assessments of the geographic distribution of this damage suffered from a systematic "research bias": Because significantly more research is conducted and documented in Global North countries such as North America and Europe, these areas also showed the highest numbers of invasive species and, consequently, the most damage reports. A new study involving Dr.

Hanno Seebens, professor of modeling biological systems at Justus Liebig University Giessen (JLU) and the Senckenberg Society for Nature Research, shows that invasive species cause significantly greater damage in countries of the Global South than in the Global North. This is due to a combination of rapid economic growth and insufficient governance. The study, which also involved researchers from Switzerland and the Czech Republic, was published in the journal Science.

Measuring damage instead of counting species The international research team led by Dr. Sven Bacher (University of Freiburg, Switzerland), Dr. Petr Pyšek (Czech Academy of Sciences) and Seebens used a new methodological approach: Instead of merely counting the presence of invasive species, the scientists developed a new metric, "average impact severity." This indicator relates the number of severe impacts—such as the local extinction of native populations—to all reported local ecological impacts.

This makes the indicator independent of research bias. The basis of the work is the Global Impacts Dataset of Invasive Alien Species (GIDIAS) database, which comprises more than 22,000 documented impacts of invasive species in 172 countries. The result is a scientific correction of previous assumptions about the consequences of invasive species: While the absolute number of reported species and reports is high in the Global North, the relative severity of impacts is significantly more pronounced in the Global South.

"This is even evident in individual species," Seebens explains. "Invasive species that cause damage in both the Global South and the Global North cause 50% more harm in countries of the Global South than in countries of the Global North. Particularly in emerging economies of South America, Africa and Asia, invasions more frequently lead to catastrophic ecological consequences." Emerging economies particularly affected The study also provides an explanation for this phenomenon, which primarily affects emerging economies: These countries experience high economic growth and intensive global trade, which greatly accelerate the introduction of new invasive species.

At the same time, they often have less-developed government structures, higher corruption rates and lower capacities to manage biological invasions. "While countries of the Global North do have many invasive species, intensive ecosystem management prevents them from having massive impacts," says Bacher, the study's lead author. "In contrast, the rising economic potential of emerging economies acts as an accelerator for the introduction of invasive species, while the institutional ability to respond lags behind." Using complex statistical models, the study shows that good governance and proactive management can effectively reduce the severity of biological invasions.