Functional eradication may be the best approach to invasive species

In North America alone, invasive species cause billions of dollars in annual damages. A new study from the University of Alberta suggests that limiting the presence of non-native wildlife through functional eradication may be a more effective strategy than total annihilation.

“Rather than trying to completely eliminate invasive species that have spread over large areas, which is very challenging, functional eradication aims to limit their abundances below levels that damage the ecosystem in priority locations,” said study lead author Professor Stephanie Green.

“Resources that might otherwise be wasted on attempting complete eradication can be spread to other areas, protecting more places from impacts.”

The experts propose using a strategy called functional eradication to limit the impact of destructive and widespread invasive species. For their investigation, the researchers surveyed 232 natural resource managers and invasive species specialists in Canada and the United States.

“More than 90 percent of these folks said the most destructive invaders in their regions were spread beyond a scale at which they could eradicate them, and instead local teams were engaged in a long-term battle to suppress or contain the species,” explained Green.

At the same time, only two percent of the study participants said they had identified targets that signified when they had done enough to manage a species.

“This points to a major gap between the needs of the people who must make decisions about invasive species, and the information scientists and monitoring programs are collecting,” said study co-author Edwin Grosholz.

According to Green, managing widespread invasive species is a long-term endeavour, but not one without hope. “Involving local communities in the functional eradication process is essential for maintaining the capacity needed to continually suppress these invaders.”

The researchers pointed to an example of functional eradication among invasive lionfish. These beautiful Indo-Pacific fish, which are popular in aquariums, have spread throughout the Caribbean Sea and the Atlantic Ocean, where they prey on many native species. 

Financial incentives for catching lionfish are now helping to reduce their population below levels that affect native species in the area. The fish are being caught for food and for use in local art. 

The experts report that similar strategies can be applied to the European green crab, an invasive species found along the Pacific and Atlantic coasts in Canada and the United States, as well as Prussian carp.

“Our study shows that ecologically damaging and widespread invasive species are prime candidates for functional eradication,” said Green. “To effectively keep populations down in priority areas, targets need to be based on how many of the invasive species it takes to cause major changes in the ecosystem.”

The study is published in the journal Frontiers in Ecology and the Environment. 

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By Chrissy Sexton, Earth.com Staff Writer