In the face of dramatic and often overwhelming reports about the health of the planet, it is tempting to dismiss yet another thing to worry about. The plants and animals involved often seem trivial in isolation: can a zebra mussel, Pablo Escobar’s Colombian hippos or wild hogs really be that damaging?
Even the term “invasive species”, meaning a non-native species that has a harmful impact on other organisms and is almost always introduced by humans, is controversial.
But there are warnings in recent events that show we should take it seriously, as Sophie Kevany reported last month on the deadly wildfires in Hawaii.
On the archipelago, scientists have been warning for several years that invasive grasses – which cover almost a quarter of the islands – pose a major fire risk. The untamed non-native plants resulted in increased intensity in the fires which spread on Maui, killing at least 106 people, an example echoed by the researchers that led this week’s expert UN assessment.
There are thousand of other examples of varying severity, according to the report authors, including invasive mosquitoes that spread Zika, yellow fever and other viruses and rodents that eat chicks alive in their nests, with invasive species estimated to be costing the world at least $423bn a year.
“It’s important to note that invasive species are everywhere. All ecosystems are now being affected, even Antarctica … ,” said Prof Anibal Pauchard, one of the lead researchers. Before we used to think about non-native species as an exotic topic. Now we’re seeing this a unified problem that is interacting with other drivers of biodiversity loss.”
Governments are aware of the threat posed by their spread, which is expected to continue in the coming years, and have committed to taking mitigation action as part of this decade’s UN biodiversity targets. The researchers say we all have a part to play in helping limit their spread by being aware of what might threaten a particular ecosystem.
“It is so important to emphasise prevention. For some of these species, once they get to a certain point of establishment, once they occur in high abundance over large areas, it is really, really difficult to do things about it. This is especially the case in marine environment,” said Prof Helen Roy, co-chair of the assessment produced by the Intergovernmental Platform on Biodiversity and Ecosystem Services (IPBES), the leading UN body on biodiversity science.
So, what can you do? Well, it depends on the ecosystem but much of it relates to good hygiene and care. If you are a keen gardener, make sure you have researched the potential impact of planting non-native species. If you are traveling to a new ecosystem, make sure your equipment has been cleaned and checked for seeds. And if you see an invasive species, report it. Action can often be taken before it spreads too far.
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