Are invasive plants a problem in Europe? Controversial views among invasion biologists

Feb 03, 2014
This image shows an invasion by knotweed at the side of the river Cassarate in Lugano, Switzerland. Credit: Franziska Humair

Some introduced (i.e. non-native) plants become abundant, threaten species richness and the well-functioning of ecosystems, the economy, or health (plant invasion). Environmental policies that attempt to restrict the expansion of non-native species are based on a consensus among scientific experts that invasions are a serious environmental problem. An example of a problematic non-native species in many parts of the world is Fallopia japonica, the Japanese knotweed that negatively affects river ecosystems.

A consensus among experts on the severity of seems evident in many scientific and outreach publications. However, instead of consensus, a new study by an interdisciplinary research team at ETH Zurich (Switzerland) of psychologists and plant biologists found a wide range of different opinions among scientific experts about how to describe , and how severe their effects on the environment are. The study is published in the latest issue of the open access journal NeoBiota.

The researchers conducted 26 face-to-face interviews with a representative sample of German-speaking scientists working on plant invasions, or more generally on environmental change, in Europe. The interviews revealed that individual understandings of scientific concepts, uncertainties, and value-based attitudes towards and their management diverged widely among these experts.

"Particularly, ambiguous definitions of the terms non-native and invasive (two key notions in invasion science) are a strong source of misunderstandings among scientists," said lead author Franziska Humair, a doctoral student at ETH Zurich. Some of the study participants used a biological definition to discriminate native from non-native ("species from a different biogeographic region"), while others referred to culture ("species not familiar to local people"). "Based on each definition, a different set of species is considered non-native in a particular country," Ms Humair said. Equally, different experts considered different impacts by invasive species on ecosystems and their functioning for humans (ecosystem services) to be relevant. "These ambiguous interpretations of key notions and divergent assessments of impacts may then lead to conflicting risk assessments and pronounced misunderstandings, eventually impeding concerted management action," concluded Ms Humair.

The authors propose that invasive species management would strongly profit from broader participation of different expert groups and stakeholders in research and management, making scientific uncertainties as well as diverging opinions towards management goals transparent.

Explore further: New warning system to find invasive species in Welsh seas

More information: Humair F, Edwards PJ, Siegrist M, Kueffer C (2014) Understanding misunderstandings in invasion science: why experts don't agree on common concepts and risk assessments. NeoBiota 20: 1. DOI: 10.3897/NeoBiota.20.6043

add to favorites email to friend print save as pdf

Related Stories

First analysis of invasive plant impacts worldwide

May 20, 2011

This week the scientific journal Ecology Letters has published a synthesis of the ecological impacts of invasive plants worldwide. This global analysis has been based on more than one thousand studies that in total descri ...

Impacts of plant invasions become less robust over time

Nov 20, 2013

Among the most impressive ecological findings of the past 25 years is the ability of invasive plants to radically change ecosystem function. Yet few if any studies have examined whether ecosystem impacts ...

Recommended for you

Dwindling wind may tip predator-prey balance

Sep 19, 2014

Bent and tossed by the wind, a field of soybean plants presents a challenge for an Asian lady beetle on the hunt for aphids. But what if the air—and the soybeans—were still?

Asian stars enlisted to fight African rhino poaching

Sep 19, 2014

Increasingly desperate South African conversationists are turning to a multi-national team of "rhino ambassadors" to try to end the scourge of poaching—and Vietnamese pop diva Hong Nhung has been recruited ...

Tropical fish a threat to Mediterranean Sea ecosystems

Sep 18, 2014

The tropical rabbitfish which have devastated algal forests in the eastern Mediterranean Sea pose a major threat to the entire Mediterranean basin if their distribution continues to expand as the climate ...

User comments : 0