Invasive species, which cause extensive harm to crops, devastate forests, facilitate the spread of diseases, and disrupt ecosystems, are rapidly proliferating worldwide, with humanity struggling to contain their expansion, according to a significant scientific assessment released on Monday.
This failure to control invasive species is resulting in annual damages and income losses exceeding $400 billion, which is equivalent to the GDP of countries like Denmark or Thailand. However, experts believe this estimate significantly underrepresents the true costs. The report is published by the intergovernmental science advisory panel for the UN Convention on Biodiversity (IPBES).
The report highlights examples of invasive species wreaking havoc, from the proliferation of water hyacinth in Lake Victoria in East Africa to the decimation of bird species by rats and brown snakes in the Pacific. Mosquitoes are also spreading diseases like Zika, yellow fever, and dengue to new regions. The assessment identifies over 37,000 alien species that have established themselves far from their native habitats, and this number is steadily increasing. Moreover, the economic toll from their damage has quadrupled on average every decade since 1970.
The report predicts that economic growth, population growth, and climate change will further amplify the frequency and scale of biological invasions and their impacts. Shockingly, only 17 percent of countries have implemented laws or regulations to address this ongoing crisis.
It’s important to note that whether accidentally or intentionally, human actions are responsible for the introduction of non-native species to distant ecosystems. The widespread dispersal of these species serves as compelling evidence that human activities have dramatically altered natural systems to the extent that scientists now consider the Earth to have entered a new geological era known as the Anthropocene.
Let’s look at examples
The proliferation of water hyacinth in Lake Victoria, covering up to 90 percent of its surface and causing disruptions in transport, aquatic life, hydroelectric dams, and promoting mosquito breeding, is believed to have originated from Belgian colonial officials in Rwanda who introduced it as an ornamental garden flower. Subsequently, it found its way into Lake Victoria via the Kagera River in the 1980s.
The Florida Everglades,1The Florida Everglades is known as a large subtropical wetland ecosystem located in the southern part of the state of Florida. This region forms one of the largest natural wetlands in the United States and is recognized worldwide as an important ecoregion. Stretching along the southern tip of Florida, the Everglades includes protected areas such as Everglades National Park. on the other hand, is now home to a multitude of destructive species descended from former pets and house plants. This includes Burmese pythons reaching lengths of five meters, walking catfish, Old World climbing fern, and Brazilian pepper.
In the 19th century, English settlers brought rabbits to New Zealand for hunting and sustenance. When the rabbit population exploded, authorities introduced stoats to control them. However, these stoats turned their attention to easier prey, leading to the decline of numerous native bird species.
New Zealand and Australia, which faced similar challenges with rabbits, serve as cautionary tales of using one introduced species to control another, according to Elaine Murphy, a scientist at New Zealand’s Department of Conservation.
In many cases, invasive species unintentionally arrive in new areas, hitchhiking in cargo ship ballast water, containers, or even tourists’ luggage. The Mediterranean Sea, for instance, is now home to non-native fish and plants like lionfish and killer algae that traveled from the Red Sea through the Suez Canal.
Murder hornets, capable of decimating entire bee colonies, are believed to have reached the United States from Asia as stowaways in freight shipments.
Europe and North America have the highest concentrations of invasive species due to extensive trade, as highlighted in the IPBES report. Invasive species are responsible for 60 percent of documented plant and animal extinctions, making them one of the five main drivers alongside habitat loss, global warming, and pollution.
These drivers often interact, with climate change pushing invasive species into newly warmed areas where native species may be ill-equipped to deal with unfamiliar intruders.
A tragic example of this occurred in Hawaii, where a devastating fire in the town of Lahaina on Maui was exacerbated by bone-dry grasses introduced decades ago for livestock feed, which had spread across abandoned sugar plantations.
In December of the previous year, a global treaty to safeguard biodiversity was formulated in Montreal, setting a goal to halve the rate at which invasive alien species spread by 2030.
References: https://www.sciencealert.com/giant-study-warns-invasive-alien-species-are-spreading-out-of-control
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