Invasive species with charisma are harder to eradicate

By Brooks Hays
Efforts to cull or relocate the West's free-roaming horses have met fierce opposition. Photo by Steve Petersen/ESA
Efforts to cull or relocate the West's free-roaming horses have met fierce opposition. Photo by Steve Petersen/ESA

Feb. 4 (UPI) -- Charismatic invaders are harder to expel, according to a new study of animal experts.

In an effort to improve the efficacy of management and eradication plans for invasive and introduced species, scientists set out to understand why people are more accepting of certain introduced species, and how public perception of a species is often at odds with it's ecological impact.


Humans tend to view animals that don't bite, crawl or squirm more favorably, surveys show. Culturally valued species can also quickly endear themselves to the public. People are less accepting of species that are slimy or oily.

These preferences explain why citizens and stakeholders are enthusiastic about plans and efforts to eradicate zebra mussels, but are less supportive of measures to control or reduce the population of ring-necked parakeets in California.

When researchers analyzed the problem, they realized the disconnect between different time and spatial scales influence on how people perceive the problem of invasive species.

Humans experience the presence of animals within an ecosystem at human timescales. An animal that has been present for 40 years will seem like a constant in the environment -- but 40 years on ecological timescales is a blink of an eye.


Humans also experience introduced species on localized scales -- in their parks or neighborhoods. But a species' ecological impact can span thousands of miles.

In other words, species that seem to humans to have been around forever without causing any obvious harm in the local ecosystem are, in reality, newcomers with the potential to affect large-scale change.

Cultural importance also has a significant influence, researchers explained in their new study -- published this week in the journal Frontiers in Ecology and the Environment.

In the West, feral or free-roaming horses, Equus caballus, continue to live on federally managed rangelands. Efforts to cull or relocate these fast-reproducing non-native animals have met fierce opposition. This is because the horse has played a significant role in much of human history and remains culturally significant, especially in the West.

Conflicts over how to manage free-roaming horses are also influenced by divergent scales.

"Horses can move very far, but their management areas can be small and the boundaries do not shift over time or account for seasonal movement," Erik A. Beever, researcher with the U.S. Geological Survey, said in a news release.

Beever and his colleagues hope that by highlighting the way different time and spatial scales influence conservation and population control decisions, policy makers can develop more effective management plans.


"There are tools, techniques, and approaches that can help to bring progress and even resolution to these situations," Beever said. "Addressing social-ecological mismatches will be an important element to effectively manage introduced species; this will require early, meaningful communication about complex management issues among researchers, managers, and the public, and a collaborative search for practical solutions and compromises."

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