Invasive species are wreaking havoc and upending ecosystems faster than ever before and not only is it happening across the world but humans have been unable to stop its spread, costing the global economy over $400 billion every year, according to a report by the United Nations published on Monday (September 4).
With the rise in the spread of invasive species, the world has seen economic damages quadruple every decade since 1970, the UN Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services (IPBES) noted, in its findings.
The failure to stem the tide of the so-called “alien species” in the world’s ecosystems, also costs the world at least $423 billion in damages and income every year, said the UN assessment. To put this number into perspective, the amount is equivalent to the GDP of Denmark or Thailand but the scientists have still called it a “gross underestimation,” as per AFP.
The findings are based on a four-year assessment of the global impacts of some 3,500 harmful invasive species conducted by a team of 86 researchers from 49 countries. Notably, so-called alien invaders also played a key role in 60 per cent of recorded plant and animal extinctions.
‘Alien species’ wreaks havoc across the world
From water hyacinths choking fishing grounds and water bodies to rats and snakes gobbling up bird eggs and wiping out entire species in the Pacific and non-native grasses that helped fuel and intensify the deadly wildfires in Hawaii; environmental chaos has been sown by invasive species across the world.
Not to mention the mosquitoes exposing new regions to Zika, yellow fever, dengue and other diseases as the report also noted the role of more than 37,000 so-called alien species that have taken root far away from their places of origin.
At least three-quarters of the negative impacts from invasive species occur on land, particularly in forests, woodlands, and farmed areas, said the UN report.
Simply put, invasive species are plants or animals, often moved due to human activity, which can take root – literally in some cases – and have detrimental effects on an environment and while the effects are slow to materialise they can be catastrophic.
“We also know this is a problem that is going to get much, much worse,” said ecologist Helen Roy, co-chair of the IPBES. This comes as warmer temperatures due to climate change are expected to make things worse and drive the expansion of invasive species.
The report has also concluded by saying that factors such as economic expansion, population increase and climate change “increase the frequency and extent of biological invasions and the impacts of invasive alien species.”
But we only have ourselves to blame. According to the researchers whether by accident or on purpose non-native species end up on the other side of the world due to human activity.
More often than not, invasive species are accidental arrivals like ballast water of cargo ships or a tourist’s suitcase.
They also said that this is hard evidence of the rapid expansion of human activity which has radically altered natural systems and tipped the Earth to a new geological epoch, the Anthropocene.
How big is threat of invasive species?
“Invasive alien species are a major threat to biodiversity and can cause irreversible damage to nature, including local and global species extinctions, and also threaten human wellbeing,” wrote Roy, Professor Anibal Pauchard and Professor Peter Stoett, who led the research.
The researchers also noted that while “specific species that inflict damage vary from place to place, these are risks and challenges with global roots but very local impacts facing people in every country, from all backgrounds and in every community – even Antarctica is being affected.”
“Invasive species are affecting not only nature but also people and causing terrible loss of life,” said Pauchard who is also the report co-chair.
One of the most recent examples of this is the wildfires in Hawaii last month which claimed the lives of at least 115 people and are said to be driven by flammable invasive grasses which, scientists say, were brought over from Africa as livestock pasture.
According to Roy, invasives can show up in several forms, including microbes, and invertebrates but plants, and animals often have the greatest environmental impact, particularly predators.
Once introduced and established in an environment, getting rid of invasive species is difficult. While some small islands have witnessed some success in eradicating invasive rats and rabbits with trapping and/or poisoning; larger populations pose a challenge.
The report also noted that only 17 per cent of countries have measures, laws or regulations to manage this onslaught of invasive species.
“Birds in New Zealand had no experience with rats until humans came and brought rats. Their nests are at ground level,” said Pauchard, speaking about how many island species had previously evolved without predators which made them “very naive”.
Meanwhile, invasive plants often reportedly leave their seeds lying dormant in the soil for years.
Therefore, the IPBES outlines general strategies to combat invasive species which include prevention, eradication and then, failing that, containment. However, prevention measures through border biosecurity and import controls are most effective, said the scientists.
In a bid to save biodiversity, at least 190 countries have committed to placing 30 per cent of land and water under protection by 2030, in line with a global treaty hammered out in Montreal last December.
The Kunming-Montreal Global Biodiversity Framework also aims to reduce the rate at which invasive alien species spread by half by 2030.
(With inputs from agencies)
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