Ann Arbor, Michigan - Invasions from alien plants, animals and pathogens threaten the economies and livelihoods of residents in some of the world's poorest nations, according to a new study by an international research team including a University of Michigan biologist.

One-sixth of the global land surface is highly vulnerable to invasion, including substantial areas in developing countries and biodiversity hotspots, according to a study published online Aug. 23 in Nature Communications.

"In the coming years, the negative impacts associated with the introduction of harmful species will likely be exacerbated by other global stressors, such as climate change, landscape degradation and pollution," said study co-author Ines Ibañez, associate professor at the U-M School of Natural Resources and Environment.

"Developed and developing countries—especially the latter—may lack the operational infrastructure to prevent and deal with harmful introductions."

The damage caused by non-native species—in the Great Lakes region, the harmful invaders include zebra and quagga mussels, the emerald ash borer and the sea lamprey—threaten global biodiversity and cost global economies $1.4 trillion annually. They can transmit disease, choke river systems and wells, prevent cattle from grazing, and out-compete or eat native species.

This is often seen as a First World problem. The new study shows that the invasions are also threatening the last remaining biodiversity strongholds in the world's most fragile economies.

Global threats from invasive alien species infographic. Image courtesy: Ines Ibanez

Increasing globalization—especially imports of pets and plants—has caused many of the biological invasions in the past. In the future, air travel will be responsible for biological invasions of Africa and Asia. This will be exacerbated by climate change and intensifying agriculture, which make it easier for invasive species to become established, according to the study authors.

Rich nations are accustomed to the nuisance of invasive alien species and are increasingly taking protective action. The study outlines how poorer economies are crucially reliant on international trade and have little power to regulate imports, so the introduction of highly dangerous species continues unchecked.

The research team evaluated the global 21st century threat from invasive species and found that many developing nations do not have the resources or plans needed to respond properly. The researchers hope their findings will lead governments and nongovernmental organizations to improve schemes to warn communities of the threats of biological invasion and to provide solutions.

"Rampant globalization will lead to invasions in countries with the least capability to deal with them," said lead author Regan Early of the University of Exeter. "We need more international cooperation and for the U.S., Australia and nations in Europe to share expertise."

The researchers collected information about trade—particularly plants, pets and air travel—and compared it to data about climate change, wildlife and agriculture to model where invasions are likely to be identified.

Biological invasions in the developing world so far have included Panama disease, which wiped out banana plantations in Central and South America, and prickly pear, which devastated grassland in Africa, leading to cattle being malnourished and people losing their livelihoods. A new strain of Panama disease currently threatens the global banana market.

The Nature Communications paper is titled "Global threats from invasive species in the 21st century and national response capacities."

Additional co-authors are from the University of Massachusetts, Amherst; Purdue University; University of Washington; U.S. Department of Agriculture; U.S. National Park Service; University of California, Berkeley; University of California, Davis; Stanford University; University of California, Irvine; University of Southampton; U.S. National Institutes of Health; and Flowminder Foundation.

The analysis was conducted as part of the Climate Change & Invasive Species Working Group (supported by the National Center for Ecological Analysis and Synthesis, which is funded by the National Science Foundation); University of California, Santa Barbara; and state of California. The work was supported by the NERC Great Western Four+ Doctoral Training Partnership.