Alien Invasions Causing Extinctions

New research published in the journal Frontiers in Ecology and the Environment on March 4, 2019, indicates that alien invasions are causing extinctions of native animals. Humans are mostly to blame.

When humans throw the world of plants and animals out of balance, the result is extinctions. We can destroy God’s designed balance when we introduce a non-native species into an environment. The introduced species without natural predators uses up local resources leaving native species without food. There are many examples.

One example is the brown tree snake (Boiga irregularis) which was accidentally introduced to Guam aboard a military cargo ship after World War II. Those snakes are native to Australia and Indonesia where natural predators control them. On Guam, they have decimated 50 percent of the native bird and lizard species and two of the three bat species on the island. The brown tree snakes considered those native species to be tasty treats, and the snakes had no predators to control them. The result was the extinction of many species, some of which existed nowhere else on Earth. Alien invasions of brown tree snakes forever changed the ecosystem of Guam.

In other cases, humans throw nature out of balance by their direct actions. An example of that is the over-hunting of sea otters. Sea otters kept the purple sea urchins in check. Steller’s sea cows (Hydrodamalis gigas)were giant relatives of manatees, and they lived on kelp. Without control by sea otters, the purple sea urchins ate so much of the kelp that Steller’s sea cows had no food, and they became extinct. However, the research project indicated that direct interference by humans in cases like this has less impact on extinctions than the alien invasions have.

Sometimes humans make the mistake of bringing in another non-native species to control the first one. That technique often makes the problems worse. Usually, by the time people discover the problem of alien invasions, it’s too late to fix it.

The research concludes that 25 percent of plant extinctions and 33 percent of animal extinctions were caused by alien invasions – the introduction of non-native species. The bottom line is that humans have not been good stewards of the planet God has given us to enjoy and protect. God gave humans the responsibility to have dominion over creation and “rule over the fish of the sea and the birds of the air and over every living creature that moves on the ground” (Genesis 1:28). Romans 13:1-4 indicates that those who rule over people have the responsibility to protect. We might say the same of us who rule over the creatures.

— Roland Earnst © 2019