Invasive species are among the most dangerous threats to biodiversity, especially native species. Around 42 percent of endangered or vulnerable species are at risk due to invasive species.

Not only biodiversity but economics and human health are also at risk due to invasive species. The severe impacts of invasive species on ecosystems, habitats, and the economy cost billions of dollars every year. Several human agricultural, commercial and recreational activities depend on the health of our native ecosystems and their biodiversity.

Research suggests that the transport of goods around the world, climate change, and economic development like energy consumption and land use are the major drivers of invasive species across various social and ecological contexts. Other drivers include recreation, migration, tourism, population changes, and pollution.

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What are Invasive Species?

An invasive species is an animal or plant species that are not native, indigenous, or not from a particular ecosystem or region. They can be any living organism like an amphibian (like a cane toad), insect, fish, plant, fungus, bacteria, or even a seed or an organism’s egg. As mentioned before, they can damage the environment, economy, and even human health.

Usually, species that reproduce and flourish quickly, and spread rapidly or aggressively, likely to cause damage or harm to other native species, are given the label “invasive”. However, not all non-native organisms are invasive. For instance, almost all the food crops grown in the United States are not native to the country, such as rice, wheat, and tomatoes. They are not invasive as they do not harm the environment, ecosystem, or biodiversity.

Invasive species do not always have to come from another country. For instance, lake trout is a native species in the Great Lakes. However, they are an invasive species in Yellowstone Lakes in Wyoming because they fight with native cutthroats for territory.

Several native species get accidentally introduced to new areas. For instance, Zebra mussels are native to the Caspian Sea and the Black Sea in Central Asia. They entered the Great Lakes of America by accident, stuck to ships that travel between two regions. Today, there are many zebra mussels in the Great Lakes, which have severely threatened native species.

Threats To Biodiversity

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Invasive species cause several threats to biodiversity. When an invasive species arrive in a new area or ecosystem, it has no natural predators or controls. The species will eventually breed and spread, taking over the new area. Native species do not have defenses to fight against invasive species, or they may not compete with a species that has no predator.

Some direct threats of invasive species include outcompeting native species for food and other resources, preying on native species, carrying and spreading diseases, preventing native species from reproducing, and killing their young.

Invasive species can modify the food web in their habitat by replacing or destroying native food sources. They may also provide little or no food value to wildlife. Invasive plant species like kudzu can replace a diverse ecosystem with a monoculture of just kudzu. Some invasive species can alter the conditions in an ecosystem, like changing the soil chemistry or the intensity of wildfires.

According to several international experts, a moderate increase in the spread of invasive species will likely cause severe damage to biodiversity and ecosystems worldwide. Invasive species can disrupt ecosystems’ perfect balance and stability when they begin to prosper in their new environment. For example, rabbits pose a great risk to native species all around the world, as they destroy plants, compete with other native animals for food, help predators to thrive, and erode the soil. Out of 170 extinct species worldwide, invasive species contribute to the extinction of 91 species and are the only contributors to the extinction of 34 species.

Experts say that invasive species in Australia pose a bigger threat than climate change to biodiversity. It is an issue faced by islands and isolated continents; scientists predict it will likely increase in other regions in the coming years.