Buzz
While earthworms may appear harmless, they are actually non-native to many regions and can disrupt forest ecosystems.
Panama7/iStock/ThinkstockScientists warn that species are currently going extinct at an unprecedented rate. There are multiple factors contributing to this, such as habitat destruction and climate change, but the spread of invasive species has always been a major factor. An invasive species is one that has been introduced to a new environment where it doesn't naturally exist and which causes harm to the ecosystem, economy, or human health [source: IUCN "Invasive"].
The International Union for Conservation of Nature (IUCN) tracks the conservation status of plants and animals, categorizing them as threatened, endangered, or safe. They produce the Red List, which serves as the authoritative resource on endangered species. In a study focusing on extinctions caused by invasive species, researchers found that of 170 extinct animal species with a known cause of extinction, invasive species were a contributing factor in 91 cases and the sole cause in 34 cases [source: Clavero].
In island ecosystems today, invasive species are considered one of the leading causes of extinction [source: Clout]. The threat posed by these species is so serious that the United Nations has issued guidelines to reduce the risk. Among the top contributors to species extinction are exotic pets, which are often released or escape, and species used as live bait [source: IUCN "United Nations"]. For instance, the common earthworm, often used in fishing, is also seen as a danger to forest ecosystems.
National Geographic reports that several species have vanished due to the introduction of invasive species, including:
- The Yunnan lake newt, which became extinct in China in 1979 partly because of the invasion of exotic fish and frogs in its habitat.
- The Hawaiian thrush, which went extinct by 1985 due to the impact of invasive predators.
- The Guam broadbill, a bird species that disappeared after the introduction of the brown tree snake in 1983.
With growing concerns about a potential mass extinction event, preventing invasive species from destroying native plants and animals is a crucial part of preserving life on Earth.
