Invasive species are non-native plants, animals, or microorganisms that cause harm to the environment, economy, or human health when they are introduced to a new area.
They can disrupt ecosystems, spread diseases, damage crops, and threaten native biodiversity.
According to a landmark report by the UN-backed science advisory panel for the UN Convention on Biodiversity, invasive species are one of the main drivers of the global biodiversity crisis and cost society more than $423 billion a year.
The report warns that the problem of invasive species is rising at an "unprecedented rate" and will get worse before it gets better.
How are invasive species spreading across the world?
One of the main factors that facilitate the spread of invasive species is the increase in global trade and travel.
Many invasive species hitch a ride on cargo ships, planes, trains, or vehicles that transport goods and people across continents.
For example, the Asian long-horned beetle, a pest that attacks hardwood trees, arrived in North America and Europe in wooden packing materials from China.
Some invasive species are also intentionally introduced by humans for various purposes, such as agriculture, aquaculture, hunting, or pet trade.
For instance, the cane toad was brought to Australia from South America to control sugar cane pests, but instead, became a menace to native wildlife.
Another factor that contributes to the spread of invasive species is climate change. As the climate warms and shifts, some invasive species can expand their range and colonize new areas that were previously unsuitable for them.
For example, the red fire ant, a stinging insect native to South America, has invaded parts of North America, Australia, Asia, and Africa due to its ability to tolerate higher temperatures and droughts.
Climate change can also make native species more vulnerable to invasions by altering their habitats, food sources, or interactions with other species.
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What are the impacts of invasive species on the environment and society?
Invasive species have negative impacts on both the environment and society in many ways.
They can compete with and prey on native species, reducing their population size and diversity. They can also alter ecosystem functions and services, such as nutrient cycling, water quality, pollination, and carbon sequestration.
They can affect human health by transmitting diseases and parasites, such as malaria, Lyme disease, West Nile virus, and schistosomiasis.
These creatures can also cause economic losses by damaging crops, livestock, fisheries, forestry, infrastructure, and tourism, and affect cultural values and identities by threatening heritage sites, sacred species, or traditional practices.
The report estimates that the damages caused by invasive species amounted to $423 billion in 2019, but this is likely a gross underestimation as many costs are hidden or intangible.
The report also projects that the number of invasive species will increase by 36 percent by 2050 under current trends, but this could be much higher if other drivers such as population growth, land use change, and climate change worsen.
How can we prevent and manage invasive species?
The report calls for urgent action to prevent and manage invasive species at local, national, regional, and global levels.
It recommends adopting a "three-stage hierarchical approach" that consists of prevention, early detection and rapid response, and long-term control and eradication.
Prevention is the most effective and cost-efficient strategy to avoid the introduction and establishment of invasive species.
It involves implementing biosecurity measures such as border inspections, quarantine regulations, risk assessments, public awareness campaigns, and codes of conduct for different sectors.
Early detection and rapid response are the next best option to eliminate or contain new invasions before they become widespread and costly.
It requires developing surveillance systems, reporting mechanisms, contingency plans, eradication methods, and emergency funds.
Long-term control and eradication are the last resort when prevention and early detection fail or are not feasible. It involves applying physical
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