Science: Ratted out

A short sustainability article in Scientific American is a nice reminder that on planet Earth, things are connected and life affects life. Alaska's Hawadax Island, used to be known as Rat Island due to a 1780s Japanese shipwreck that released rats on the island. The rats took over and wiped out all the seabirds. That wrecked the local ocean ecosystem, all the way down to algae. Rat poison was spread over the island and the rat population was completely wiped out. By 11 years later, things had returned to normal. SciAm writes:

Nowadays Hawadax is once again a noisy place. Roughly a decade after a successful effort to rid the island of its predatory rodents, a bounty of seabirds has returned. And the benefits have extended across the island's entire seashore ecosystem, which again teems with diverse life. These findings, published in Scientific Reports, show that certain ecosystems can recover with surprising speed if given the chance.

Researcher Carolyn Kurle's first findings, published in 2008, showed that the rats affected not just birds but the entire food chain—all the way down to algae. Without birds to eat seashore invertebrates, populations of snails, limpets and other herbivorous species exploded and gobbled up much of the marine kelp, which provides crucial habitat for other organisms. “Certain invasive species can have impacts beyond those that are most obvious,” Kurle says.

They found that its intertidal ecosystem had steadily recovered and now resembles that of other Aleutian Islands that were never invaded by rats, with significantly fewer marine invertebrates and much more kelp cover.

De-ratification of invasive rats is a good thing. What about other invasive species?

By Germaine, the science guy