Throughout history, humans have relocated animals from one part of the world to another. Sometimes the relations are on purpose, an attempt to help introduce a species to a new region. In other situations, animal species are accidentally carried as stowaways on ships and can enter new lands when the ship enters a port.
Not all alien animal species will have an adverse impact on the environment, but a stout number of those that make their way to a new region in the world quickly become invasive to the ecosystem of which they’re introduced.
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Published in the journal Ecology & Evolution, researchers from Durham University lay out their evidence for some of the world’s hotspots for invasive alien animal species, citing islands and coastlines as some of the most notable.
Among those, the research flagged the islands of Hawaii, Northern islands of New Zealand, and Indonesia’s Lesser Sunda Islands as some of the major hotspots teeming with alien animal life that wouldn’t be there if it weren’t for humans moving them around.
The team, led by Wayne Dawson, was careful to take several animal groups into consideration, including eight animal groups in total: amphibians, ants, birds, freshwater fish, mammals, reptiles, spiders, and vascular plants.
“Our research shows that, islands and mainland coastal regions contain higher numbers of established alien plants and animals, and this may be because these areas have major points of entry like ports,” Dawson explained.
“In general, regions that are wealthier, and where human populations are denser also have more alien species, but these effects are stronger for islands.”
As the world becomes more profoundly connected by way of private and public transportation, we can expect the introduction of alien animal species to rise in certain areas.
Regions containing higher volumes of airports and ports are prime examples of those were alien animal species are likely to appear. These are the key entry points of our transportation systems, and visitors sometimes bring animals with them, or animals get trapped inside when the doors close.
Not all alien animal species will negatively influence an ecosystem, but in several cases throughout time, native species have proven incompatible with alien animal species.
Some great examples of alien animal species wreaking havoc on environments are goldfish in our freshwater sources, the Burmese python on Florida, and the gray squirrel in the UK. Several other examples exist, but the list would be too long to summarize in this piece.
“Many of these incoming species are useful, and won't establish and spread in their new homes, but some will, with varying levels of impact on resident species and ecosystems,” Dawson continued.
“The challenge for us is to understand what the consequences are of mixing up the world's species in this way, to decide how to deal with this change, and what measures we can put in place to try and prevent further introductions to the most vulnerable regions.”
Worthy of note, not all alien animal species come from human intervention. Sometimes, animals find their way to new places on their own. Likewise, sometimes the introduction of new animals has a positive impact, but many times, it does not.
There is still a bevy of research that needs to be done to understand how most of the world’s alien animal species move from one place of the world to another. Likewise, learning how these animals impact an ecosystem is a critical component for successful animal conservation.